From 2b484eda5d78dd4d7d2f03da26e5d0ad82e9faef Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Thu, 27 Nov 2025 15:02:04 +0100
Subject: [PATCH 01/45] feat: add `isAddedDiffFile` and `isRemovedDiffFile` git
 util functions

---
 scripts/utils/Git.ts | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/scripts/utils/Git.ts b/scripts/utils/Git.ts
index 4b5ed7a2d9b9b..ce1a5ea94bf07 100644
--- a/scripts/utils/Git.ts
+++ b/scripts/utils/Git.ts
@@ -278,6 +278,44 @@ class Git {
         };
     }
 
+    /**
+     * Check if a file from a Git diff is added.
+     *
+     * @param file - The file to check
+     * @returns true if the file is added, false otherwise
+     */
+    static isAddedDiffFile(file: FileDiff): boolean {
+        const hasAddedLines = file.addedLines.size > 0;
+        const hasModifiedLines = file.modifiedLines.size > 0;
+        const hasRemovedLines = file.removedLines.size > 0;
+
+        if (!hasAddedLines) {
+            return false;
+        }
+
+        const hasOnlyAdditions = !hasModifiedLines && !hasRemovedLines;
+        return hasOnlyAdditions;
+    }
+
+    /**
+     * Check if a file from a Git diff is removed.
+     *
+     * @param file - The file to check
+     * @returns true if the file is removed, false otherwise
+     */
+    static isRemovedDiffFile(file: FileDiff): boolean {
+        const hasRemovedLines = file.removedLines.size > 0;
+        const hasModifiedLines = file.modifiedLines.size > 0;
+        const hasAddedLines = file.addedLines.size > 0;
+
+        if (!hasRemovedLines) {
+            return false;
+        }
+
+        const hasOnlyRemovals = !hasModifiedLines && !hasAddedLines;
+        return hasOnlyRemovals;
+    }
+
     /**
      * Calculate the line number for a diff line based on the hunk and line type.
      */

From 13e2d8dcf78a11cc941535d0c40ec2632410f6a7 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Thu, 27 Nov 2025 15:03:21 +0100
Subject: [PATCH 02/45] feat: check for added files and manual memoization

---
 scripts/react-compiler-compliance-check.ts | 209 ++++++++++++++++++++-
 1 file changed, 200 insertions(+), 9 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 9412dc61a61b7..340b99ce17337 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -7,11 +7,12 @@
  * It provides both CI and local development tools to enforce Rules of React compliance.
  */
 import {execSync} from 'child_process';
-import {writeFileSync} from 'fs';
+import {readFileSync, writeFileSync} from 'fs';
 import {join} from 'path';
 import type {TupleToUnion} from 'type-fest';
 import CLI from './utils/CLI';
 import Git from './utils/Git';
+import type {DiffResult} from './utils/Git';
 import {log, bold as logBold, error as logError, info as logInfo, note as logNote, success as logSuccess, warn as logWarn} from './utils/Logger';
 
 const TAB = '    ';
@@ -24,6 +25,28 @@ const SUPPRESSED_COMPILER_ERRORS = [
     '(BuildHIR::lowerExpression) Expected Identifier, got MemberExpression key in ObjectExpression',
 ] as const satisfies string[];
 
+type ManualMemoizationPattern = {
+    keyword: string;
+    regex: RegExp;
+};
+
+const MANUAL_MEMOIZATION_PATTERNS: ManualMemoizationPattern[] = [
+    {
+        keyword: 'memo',
+        regex: /\b(?:React\.)?memo\s*\(/g,
+    },
+    {
+        keyword: 'useMemo',
+        regex: /\b(?:React\.)?useMemo\s*\(/g,
+    },
+    {
+        keyword: 'useCallback',
+        regex: /\b(?:React\.)?useCallback\s*\(/g,
+    },
+];
+
+const NO_MANUAL_MEMO_DIRECTIVE_PATTERN = /["']use no memo["']\s*;?/;
+
 const ESLINT_DISABLE_PATTERNS = {
     FILE_KEYWORDS: ['// eslint-disable ', '/* eslint-disable '],
     LINE_KEYWORDS: ['// eslint-disable-next-line ', '/* eslint-disable-next-line '],
@@ -52,6 +75,12 @@ type CompilerFailure = {
     reason?: string;
 };
 
+type ManualMemoizationMatch = {
+    keyword: string;
+    line: number;
+    column: number;
+};
+
 type DiffFilteringCommits = {
     fromRef: string;
     toRef?: string;
@@ -67,6 +96,7 @@ type BaseCheckOptions = PrintResultsOptions & {
     reportFileName?: string;
     shouldGenerateReport?: boolean;
     shouldFilterByDiff?: boolean;
+    shouldEnforceNewComponents?: boolean;
 };
 
 type CheckOptions = BaseCheckOptions & {
@@ -81,6 +111,7 @@ async function check({
     remote,
     shouldPrintSuccesses = false,
     shouldPrintSuppressedErrors = false,
+    shouldEnforceNewComponents = false,
 }: CheckOptions): Promise<boolean> {
     if (files) {
         logInfo(`Running React Compiler check for ${files.length} files or glob patterns...`);
@@ -88,14 +119,25 @@ async function check({
         logInfo('Running React Compiler check for all files...');
     }
 
+    const shouldComputeDiff = shouldFilterByDiff || shouldEnforceNewComponents;
     const src = createFilesGlob(files);
     let results = runCompilerHealthcheck(src);
 
-    if (shouldFilterByDiff) {
+    if (shouldComputeDiff) {
         const mainBaseCommitHash = await Git.getMainBranchCommitHash(remote);
         const diffFilteringCommits: DiffFilteringCommits = {fromRef: mainBaseCommitHash};
+        const diffResult = Git.diff(diffFilteringCommits.fromRef, diffFilteringCommits.toRef);
 
-        results = await filterResultsByDiff(results, diffFilteringCommits, {shouldPrintSuccesses, shouldPrintSuppressedErrors});
+        if (shouldFilterByDiff) {
+            results = await filterResultsByDiff(results, diffFilteringCommits, diffResult, {shouldPrintSuccesses, shouldPrintSuppressedErrors});
+        }
+
+        if (shouldEnforceNewComponents) {
+            const newComponentFailures = enforceNewComponentGuard(results, diffResult, files);
+            for (const failure of newComponentFailures) {
+                addFailureIfDoesNotExist(results.failures, failure);
+            }
+        }
     }
 
     printResults(results, {shouldPrintSuccesses, shouldPrintSuppressedErrors});
@@ -272,6 +314,139 @@ function createFilesGlob(files?: string[]): string | undefined {
     return `**/+(${files.join('|')})`;
 }
 
+function getNewComponentFiles(diffResult: DiffResult, filesToCheck?: string[]): Set<string> {
+    const newFiles = new Set<string>();
+    const fileFilter = filesToCheck ? new Set(filesToCheck) : undefined;
+
+    for (const file of diffResult.files) {
+        if (!Git.isAddedDiffFile(file)) {
+            continue;
+        }
+
+        if (fileFilter && !fileFilter.has(file.filePath)) {
+            continue;
+        }
+
+        newFiles.add(file.filePath);
+    }
+    return newFiles;
+}
+
+function enforceNewComponentGuard(results: CompilerResults, diffResult: DiffResult | undefined, filesToCheck?: string[]): CompilerFailure[] {
+    if (!diffResult) {
+        return [];
+    }
+
+    const newComponentFiles = getNewComponentFiles(diffResult, filesToCheck);
+    if (newComponentFiles.size === 0) {
+        return [];
+    }
+
+    const failures: CompilerFailure[] = [];
+
+    for (const filePath of newComponentFiles) {
+        const source = readSourceFile(filePath);
+        if (!source) {
+            continue;
+        }
+
+        if (hasManualMemoOptOutDirective(source)) {
+            continue;
+        }
+
+        const hasSuppressedFailure = hasFailureForFile(results.suppressedFailures, filePath);
+        const hasCompilerFailure = hasFailureForFile(results.failures, filePath);
+        const isCompilerSuccess = results.success.has(filePath);
+
+        if (!isCompilerSuccess && !hasSuppressedFailure) {
+            if (hasCompilerFailure) {
+                continue;
+            }
+
+            failures.push({
+                file: filePath,
+                reason: 'New components must compile with React Compiler or opt out using "use no memo"; on the first line.',
+            });
+            continue;
+        }
+
+        if (hasSuppressedFailure) {
+            continue;
+        }
+
+        const manualMemoMatches = findManualMemoizationMatches(source);
+        if (manualMemoMatches.length === 0) {
+            continue;
+        }
+
+        const firstMatch = manualMemoMatches.at(0);
+        if (!firstMatch) {
+            continue;
+        }
+
+        failures.push({
+            file: filePath,
+            line: firstMatch.line,
+            column: firstMatch.column,
+            reason: `Manual memoization (${firstMatch.keyword}) is not allowed in new components.`,
+        });
+    }
+
+    return failures;
+}
+
+function hasManualMemoOptOutDirective(source: string): boolean {
+    return NO_MANUAL_MEMO_DIRECTIVE_PATTERN.test(source);
+}
+
+function findManualMemoizationMatches(source: string): ManualMemoizationMatch[] {
+    const matches: ManualMemoizationMatch[] = [];
+
+    for (const pattern of MANUAL_MEMOIZATION_PATTERNS) {
+        pattern.regex.lastIndex = 0;
+        let regexMatch: RegExpExecArray | null;
+        // eslint-disable-next-line no-cond-assign
+        while ((regexMatch = pattern.regex.exec(source)) !== null) {
+            const matchIndex = regexMatch.index;
+            const {line, column} = getLineAndColumnFromIndex(source, matchIndex);
+            matches.push({
+                keyword: pattern.keyword,
+                line,
+                column,
+            });
+        }
+    }
+
+    return matches;
+}
+
+function hasFailureForFile(failureMap: FailureMap, filePath: string): boolean {
+    for (const failure of failureMap.values()) {
+        if (failure.file === filePath) {
+            return true;
+        }
+    }
+    return false;
+}
+
+function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
+    const substring = source.slice(0, index);
+    const line = substring.split('\n').length;
+    const lastLineBreakIndex = substring.lastIndexOf('\n');
+    const column = lastLineBreakIndex === -1 ? index + 1 : index - lastLineBreakIndex;
+    return {line, column};
+}
+
+function readSourceFile(filePath: string): string | null {
+    try {
+        const absolutePath = join(process.cwd(), filePath);
+        return readFileSync(absolutePath, 'utf8');
+    } catch (error) {
+        logWarn(`Unable to read ${filePath} while enforcing new component rules.`, error);
+        return null;
+    }
+}
+
 /**
  * Filters compiler results to only include failures for lines that were changed in the git diff.
  * This helps focus on new issues introduced by the current changes rather than pre-existing issues.
@@ -287,13 +462,11 @@ function createFilesGlob(files?: string[]): string | undefined {
 async function filterResultsByDiff(
     results: CompilerResults,
     diffFilteringCommits: DiffFilteringCommits,
+    diffResult: DiffResult,
     {shouldPrintSuccesses, shouldPrintSuppressedErrors}: PrintResultsOptions,
 ): Promise<CompilerResults> {
     logInfo(`Filtering results by diff between ${diffFilteringCommits.fromRef} and ${diffFilteringCommits.toRef ?? 'the working tree'}...`);
 
-    // Get the diff between the base ref and the working tree
-    const diffResult = Git.diff(diffFilteringCommits.fromRef, diffFilteringCommits.toRef);
-
     // If there are no changes, return empty results
     if (!diffResult.hasChanges) {
         return {
@@ -597,14 +770,32 @@ async function main() {
                 required: false,
                 default: false,
             },
+            enforceNewComponents: {
+                description: 'Ensure new components compile with React Compiler and avoid manual memoization',
+                required: false,
+                default: false,
+            },
         },
     });
 
     const {command, file} = cli.positionalArgs;
     const {remote, reportFileName} = cli.namedArgs;
-    const {report: shouldGenerateReport, filterByDiff: shouldFilterByDiff, printSuccesses: shouldPrintSuccesses, printSuppressedErrors: shouldPrintSuppressedErrors} = cli.flags;
-
-    const commonOptions: BaseCheckOptions = {shouldGenerateReport, reportFileName, shouldFilterByDiff, shouldPrintSuccesses, shouldPrintSuppressedErrors};
+    const {
+        report: shouldGenerateReport,
+        filterByDiff: shouldFilterByDiff,
+        printSuccesses: shouldPrintSuccesses,
+        printSuppressedErrors: shouldPrintSuppressedErrors,
+        enforceNewComponents: shouldEnforceNewComponents,
+    } = cli.flags;
+
+    const commonOptions: BaseCheckOptions = {
+        shouldGenerateReport,
+        reportFileName,
+        shouldFilterByDiff,
+        shouldPrintSuccesses,
+        shouldPrintSuppressedErrors,
+        shouldEnforceNewComponents,
+    };
 
     async function runCommand() {
         switch (command) {

From 7319f32fae1d6afdb0e08c4690eca56c104076df Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Thu, 27 Nov 2025 15:19:57 +0100
Subject: [PATCH 03/45] only print failures from healthcheck

---
 scripts/react-compiler-compliance-check.ts | 109 +++++++++++++++------
 1 file changed, 79 insertions(+), 30 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 340b99ce17337..8ee8929af3308 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -86,9 +86,15 @@ type DiffFilteringCommits = {
     toRef?: string;
 };
 
+type NewComponentEnforcementSummary = {
+    compilerFailures: CompilerFailure[];
+    manualMemoFailures: CompilerFailure[];
+};
+
 type PrintResultsOptions = {
     shouldPrintSuccesses: boolean;
     shouldPrintSuppressedErrors: boolean;
+    newComponentSummary?: NewComponentEnforcementSummary | null;
 };
 
 type BaseCheckOptions = PrintResultsOptions & {
@@ -113,6 +119,7 @@ async function check({
     shouldPrintSuppressedErrors = false,
     shouldEnforceNewComponents = false,
 }: CheckOptions): Promise<boolean> {
+    let newComponentSummary: NewComponentEnforcementSummary | undefined;
     if (files) {
         logInfo(`Running React Compiler check for ${files.length} files or glob patterns...`);
     } else {
@@ -133,14 +140,11 @@ async function check({
         }
 
         if (shouldEnforceNewComponents) {
-            const newComponentFailures = enforceNewComponentGuard(results, diffResult, files);
-            for (const failure of newComponentFailures) {
-                addFailureIfDoesNotExist(results.failures, failure);
-            }
+            newComponentSummary = enforceNewComponentGuard(results, diffResult, files);
         }
     }
 
-    printResults(results, {shouldPrintSuccesses, shouldPrintSuppressedErrors});
+    printResults(results, {shouldPrintSuccesses, shouldPrintSuppressedErrors, newComponentSummary});
 
     if (shouldGenerateReport) {
         generateReport(results, reportFileName);
@@ -332,17 +336,25 @@ function getNewComponentFiles(diffResult: DiffResult, filesToCheck?: string[]):
     return newFiles;
 }
 
-function enforceNewComponentGuard(results: CompilerResults, diffResult: DiffResult | undefined, filesToCheck?: string[]): CompilerFailure[] {
+function enforceNewComponentGuard(results: CompilerResults, diffResult: DiffResult | undefined, filesToCheck?: string[]): NewComponentEnforcementSummary {
     if (!diffResult) {
-        return [];
+        return {
+            compilerFailures: [],
+            manualMemoFailures: [],
+        };
     }
 
     const newComponentFiles = getNewComponentFiles(diffResult, filesToCheck);
     if (newComponentFiles.size === 0) {
-        return [];
+        return {
+            compilerFailures: [],
+            manualMemoFailures: [],
+        };
     }
 
-    const failures: CompilerFailure[] = [];
+    const manualMemoFailures: CompilerFailure[] = [];
+    const compilerFailures: CompilerFailure[] = [];
+    collectCompilerFailuresForNewComponents(results.failures, newComponentFiles, compilerFailures);
 
     for (const filePath of newComponentFiles) {
         const source = readSourceFile(filePath);
@@ -355,21 +367,6 @@ function enforceNewComponentGuard(results: CompilerResults, diffResult: DiffResu
         }
 
         const hasSuppressedFailure = hasFailureForFile(results.suppressedFailures, filePath);
-        const hasCompilerFailure = hasFailureForFile(results.failures, filePath);
-        const isCompilerSuccess = results.success.has(filePath);
-
-        if (!isCompilerSuccess && !hasSuppressedFailure) {
-            if (hasCompilerFailure) {
-                continue;
-            }
-
-            failures.push({
-                file: filePath,
-                reason: 'New components must compile with React Compiler or opt out using "use no memo"; on the first line.',
-            });
-            continue;
-        }
-
         if (hasSuppressedFailure) {
             continue;
         }
@@ -384,15 +381,20 @@ function enforceNewComponentGuard(results: CompilerResults, diffResult: DiffResu
             continue;
         }
 
-        failures.push({
+        const failure: CompilerFailure = {
             file: filePath,
             line: firstMatch.line,
             column: firstMatch.column,
             reason: `Manual memoization (${firstMatch.keyword}) is not allowed in new components.`,
-        });
+        };
+        manualMemoFailures.push(failure);
+        addFailureIfDoesNotExist(results.failures, failure);
     }
 
-    return failures;
+    return {
+        compilerFailures,
+        manualMemoFailures,
+    };
 }
 
 function hasManualMemoOptOutDirective(source: string): boolean {
@@ -429,6 +431,47 @@ function hasFailureForFile(failureMap: FailureMap, filePath: string): boolean {
     return false;
 }
 
+function collectCompilerFailuresForNewComponents(failureMap: FailureMap, newComponentFiles: Set<string>, bucket: CompilerFailure[]): void {
+    for (const failure of failureMap.values()) {
+        if (!newComponentFiles.has(failure.file)) {
+            continue;
+        }
+        bucket.push(failure);
+    }
+}
+
+function printNewComponentFailuresSection({compilerFailures, manualMemoFailures}: NewComponentEnforcementSummary): void {
+    const hasCompilerIssues = compilerFailures.length > 0;
+    const hasManualMemoIssues = manualMemoFailures.length > 0;
+    if (!hasCompilerIssues && !hasManualMemoIssues) {
+        return;
+    }
+
+    log();
+    logWarn('Added files with enforced automatic memoization:');
+    log();
+
+    if (hasCompilerIssues) {
+        logBold('Compiler errors:');
+        for (const failure of compilerFailures) {
+            const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
+            logError(`${TAB}${failure.file}${location}`);
+            logNote(`${TAB}${TAB}${failure.reason ?? 'No reason provided'}`);
+        }
+        log();
+    }
+
+    if (hasManualMemoIssues) {
+        logBold('Manual memoization detected:');
+        for (const failure of manualMemoFailures) {
+            const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
+            logError(`${TAB}${failure.file}${location}`);
+            logNote(`${TAB}${TAB}${failure.reason ?? 'No reason provided'}`);
+        }
+        log();
+    }
+}
+
 function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
     const substring = source.slice(0, index);
     const line = substring.split('\n').length;
@@ -609,7 +652,12 @@ async function filterResultsByDiff(
     };
 }
 
-function printResults({success, failures, suppressedFailures}: CompilerResults, {shouldPrintSuccesses, shouldPrintSuppressedErrors}: PrintResultsOptions): void {
+function printResults({success, failures, suppressedFailures}: CompilerResults, {shouldPrintSuccesses, shouldPrintSuppressedErrors, newComponentSummary}: PrintResultsOptions): void {
+    if (newComponentSummary) {
+        printNewComponentFailuresSection(newComponentSummary);
+    }
+    const newComponentFailureKeys = createNewComponentFailureKeySet(newComponentSummary);
+
     if (shouldPrintSuccesses && success.size > 0) {
         log();
         logSuccess(`Successfully compiled ${success.size} files with React Compiler:`);
@@ -652,7 +700,8 @@ function printResults({success, failures, suppressedFailures}: CompilerResults,
         log();
     }
 
-    const isPassed = failures.size === 0;
+    const filteredFailures = filterOutNewComponentFailures(failures, newComponentFailureKeys);
+    const isPassed = filteredFailures.size === 0;
     if (isPassed) {
         logSuccess('All files pass React Compiler compliance check!');
         return;
@@ -669,7 +718,7 @@ function printResults({success, failures, suppressedFailures}: CompilerResults,
     log();
 
     // eslint-disable-next-line unicorn/no-array-for-each
-    failures.forEach((failure) => {
+    filteredFailures.forEach((failure) => {
         const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
         logBold(`${failure.file}${location}`);
         logNote(`${TAB}${failure.reason ?? 'No reason provided'}`);

From fcc3e7792ad76d252bae0f22f84e9e1c65f5e8d9 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 14:09:43 +0100
Subject: [PATCH 04/45] fix: improve output and group together compiler errors
 with auto memo message

---
 scripts/react-compiler-compliance-check.ts | 219 +++++++++------------
 1 file changed, 90 insertions(+), 129 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 8ee8929af3308..13cc1816c6e2a 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -45,6 +45,8 @@ const MANUAL_MEMOIZATION_PATTERNS: ManualMemoizationPattern[] = [
     },
 ];
 
+const MANUAL_MEMOIZATION_FAILURE_MESSAGE = `Manual memoization is not allowed in new React component files. Please remove any manual memoization functions (\`useMemo\`, \`useCallback\`, \`memo\`) or use the \`"use no memo"\` directive at the beginning of the component.`;
+
 const NO_MANUAL_MEMO_DIRECTIVE_PATTERN = /["']use no memo["']\s*;?/;
 
 const ESLINT_DISABLE_PATTERNS = {
@@ -60,14 +62,15 @@ const VERBOSE_OUTPUT_LINE_REGEXES = {
     REASON: /Reason: (.+)/,
 } as const satisfies Record<string, RegExp>;
 
-type FailureMap = Map<string, CompilerFailure>;
-
 type CompilerResults = {
     success: Set<string>;
     failures: FailureMap;
     suppressedFailures: FailureMap;
+    enforcedAddedComponentFailures?: EnforcedAddedComponentFailureMap;
 };
 
+type FailureMap = Map<string, CompilerFailure>;
+
 type CompilerFailure = {
     file: string;
     line?: number;
@@ -75,6 +78,13 @@ type CompilerFailure = {
     reason?: string;
 };
 
+type EnforcedAddedComponentFailureMap = Map<string, ManualMemoFailure>;
+
+type ManualMemoFailure = {
+    message: string;
+    compilerFailures: FailureMap | undefined;
+};
+
 type ManualMemoizationMatch = {
     keyword: string;
     line: number;
@@ -86,15 +96,9 @@ type DiffFilteringCommits = {
     toRef?: string;
 };
 
-type NewComponentEnforcementSummary = {
-    compilerFailures: CompilerFailure[];
-    manualMemoFailures: CompilerFailure[];
-};
-
 type PrintResultsOptions = {
     shouldPrintSuccesses: boolean;
     shouldPrintSuppressedErrors: boolean;
-    newComponentSummary?: NewComponentEnforcementSummary | null;
 };
 
 type BaseCheckOptions = PrintResultsOptions & {
@@ -119,7 +123,6 @@ async function check({
     shouldPrintSuppressedErrors = false,
     shouldEnforceNewComponents = false,
 }: CheckOptions): Promise<boolean> {
-    let newComponentSummary: NewComponentEnforcementSummary | undefined;
     if (files) {
         logInfo(`Running React Compiler check for ${files.length} files or glob patterns...`);
     } else {
@@ -140,11 +143,14 @@ async function check({
         }
 
         if (shouldEnforceNewComponents) {
-            newComponentSummary = enforceNewComponentGuard(results, diffResult, files);
+            const {nonAutoMemoEnforcedFailures, addedComponentFailures} = enforceNewComponentGuard(results, diffResult);
+
+            results.enforcedAddedComponentFailures = addedComponentFailures;
+            results.failures = nonAutoMemoEnforcedFailures;
         }
     }
 
-    printResults(results, {shouldPrintSuccesses, shouldPrintSuppressedErrors, newComponentSummary});
+    printResults(results, {shouldPrintSuccesses, shouldPrintSuppressedErrors});
 
     if (shouldGenerateReport) {
         generateReport(results, reportFileName);
@@ -318,82 +324,69 @@ function createFilesGlob(files?: string[]): string | undefined {
     return `**/+(${files.join('|')})`;
 }
 
-function getNewComponentFiles(diffResult: DiffResult, filesToCheck?: string[]): Set<string> {
-    const newFiles = new Set<string>();
-    const fileFilter = filesToCheck ? new Set(filesToCheck) : undefined;
-
+function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffResult) {
+    const addedDiffFiles = new Set<string>();
     for (const file of diffResult.files) {
-        if (!Git.isAddedDiffFile(file)) {
-            continue;
+        if (Git.isAddedDiffFile(file)) {
+            addedDiffFiles.add(file.filePath);
         }
+    }
+
+    const nonAutoMemoEnforcedFailures: FailureMap = new Map();
+    const addedFileFailures = new Map<string, FailureMap>();
+    for (const [failureKey, failure] of failures) {
+        const addedFilePath = failure.file;
 
-        if (fileFilter && !fileFilter.has(file.filePath)) {
+        if (!addedDiffFiles.has(addedFilePath)) {
+            nonAutoMemoEnforcedFailures.set(failureKey, failure);
             continue;
         }
 
-        newFiles.add(file.filePath);
-    }
-    return newFiles;
-}
-
-function enforceNewComponentGuard(results: CompilerResults, diffResult: DiffResult | undefined, filesToCheck?: string[]): NewComponentEnforcementSummary {
-    if (!diffResult) {
-        return {
-            compilerFailures: [],
-            manualMemoFailures: [],
-        };
-    }
+        if (addedFileFailures.has(addedFilePath)) {
+            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+            const existingAddedFileFailuresMap = addedFileFailures.get(addedFilePath)!;
+            existingAddedFileFailuresMap.set(failureKey, failure);
+        }
 
-    const newComponentFiles = getNewComponentFiles(diffResult, filesToCheck);
-    if (newComponentFiles.size === 0) {
-        return {
-            compilerFailures: [],
-            manualMemoFailures: [],
-        };
+        addedFileFailures.set(addedFilePath, new Map<string, CompilerFailure>([[failureKey, failure]]));
     }
 
-    const manualMemoFailures: CompilerFailure[] = [];
-    const compilerFailures: CompilerFailure[] = [];
-    collectCompilerFailuresForNewComponents(results.failures, newComponentFiles, compilerFailures);
+    function addNonAutoMemoEnforcedFailures(addedFilePath: string): void {
+        const addedFileFailuresMap = addedFileFailures.get(addedFilePath);
 
-    for (const filePath of newComponentFiles) {
-        const source = readSourceFile(filePath);
-        if (!source) {
-            continue;
+        if (!addedFileFailuresMap) {
+            return;
         }
 
-        if (hasManualMemoOptOutDirective(source)) {
-            continue;
+        for (const [failureKey, failure] of failures) {
+            nonAutoMemoEnforcedFailures.set(failureKey, failure);
         }
+    }
 
-        const hasSuppressedFailure = hasFailureForFile(results.suppressedFailures, filePath);
-        if (hasSuppressedFailure) {
+    const addedComponentFailures: EnforcedAddedComponentFailureMap = new Map();
+    for (const addedFilePath of addedDiffFiles) {
+        const source = readSourceFile(addedFilePath);
+        if (!source || hasManualMemoOptOutDirective(source)) {
+            addNonAutoMemoEnforcedFailures(addedFilePath);
             continue;
         }
 
         const manualMemoMatches = findManualMemoizationMatches(source);
         if (manualMemoMatches.length === 0) {
+            addNonAutoMemoEnforcedFailures(addedFilePath);
             continue;
         }
 
-        const firstMatch = manualMemoMatches.at(0);
-        if (!firstMatch) {
-            continue;
-        }
-
-        const failure: CompilerFailure = {
-            file: filePath,
-            line: firstMatch.line,
-            column: firstMatch.column,
-            reason: `Manual memoization (${firstMatch.keyword}) is not allowed in new components.`,
+        const manualMemoFailure: ManualMemoFailure = {
+            message: MANUAL_MEMOIZATION_FAILURE_MESSAGE,
+            compilerFailures: addedFileFailures.get(addedFilePath),
         };
-        manualMemoFailures.push(failure);
-        addFailureIfDoesNotExist(results.failures, failure);
+        addedComponentFailures.set(addedFilePath, manualMemoFailure);
     }
 
     return {
-        compilerFailures,
-        manualMemoFailures,
+        nonAutoMemoEnforcedFailures,
+        addedComponentFailures,
     };
 }
 
@@ -422,56 +415,6 @@ function findManualMemoizationMatches(source: string): ManualMemoizationMatch[]
     return matches;
 }
 
-function hasFailureForFile(failureMap: FailureMap, filePath: string): boolean {
-    for (const failure of failureMap.values()) {
-        if (failure.file === filePath) {
-            return true;
-        }
-    }
-    return false;
-}
-
-function collectCompilerFailuresForNewComponents(failureMap: FailureMap, newComponentFiles: Set<string>, bucket: CompilerFailure[]): void {
-    for (const failure of failureMap.values()) {
-        if (!newComponentFiles.has(failure.file)) {
-            continue;
-        }
-        bucket.push(failure);
-    }
-}
-
-function printNewComponentFailuresSection({compilerFailures, manualMemoFailures}: NewComponentEnforcementSummary): void {
-    const hasCompilerIssues = compilerFailures.length > 0;
-    const hasManualMemoIssues = manualMemoFailures.length > 0;
-    if (!hasCompilerIssues && !hasManualMemoIssues) {
-        return;
-    }
-
-    log();
-    logWarn('Added files with enforced automatic memoization:');
-    log();
-
-    if (hasCompilerIssues) {
-        logBold('Compiler errors:');
-        for (const failure of compilerFailures) {
-            const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
-            logError(`${TAB}${failure.file}${location}`);
-            logNote(`${TAB}${TAB}${failure.reason ?? 'No reason provided'}`);
-        }
-        log();
-    }
-
-    if (hasManualMemoIssues) {
-        logBold('Manual memoization detected:');
-        for (const failure of manualMemoFailures) {
-            const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
-            logError(`${TAB}${failure.file}${location}`);
-            logNote(`${TAB}${TAB}${failure.reason ?? 'No reason provided'}`);
-        }
-        log();
-    }
-}
-
 function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
     const substring = source.slice(0, index);
     const line = substring.split('\n').length;
@@ -652,21 +595,19 @@ async function filterResultsByDiff(
     };
 }
 
-function printResults({success, failures, suppressedFailures}: CompilerResults, {shouldPrintSuccesses, shouldPrintSuppressedErrors, newComponentSummary}: PrintResultsOptions): void {
-    if (newComponentSummary) {
-        printNewComponentFailuresSection(newComponentSummary);
-    }
-    const newComponentFailureKeys = createNewComponentFailureKeySet(newComponentSummary);
-
+function printResults(
+    {success, failures, suppressedFailures, enforcedAddedComponentFailures}: CompilerResults,
+    {shouldPrintSuccesses, shouldPrintSuppressedErrors}: PrintResultsOptions,
+): void {
     if (shouldPrintSuccesses && success.size > 0) {
         log();
         logSuccess(`Successfully compiled ${success.size} files with React Compiler:`);
         log();
 
         // eslint-disable-next-line unicorn/no-array-for-each
-        success.forEach((successFile) => {
+        for (const successFile of success) {
             logSuccess(`${successFile}`);
-        });
+        }
 
         log();
     }
@@ -700,8 +641,9 @@ function printResults({success, failures, suppressedFailures}: CompilerResults,
         log();
     }
 
-    const filteredFailures = filterOutNewComponentFailures(failures, newComponentFailureKeys);
-    const isPassed = filteredFailures.size === 0;
+    const hasEnforcedAddedComponentFailures = enforcedAddedComponentFailures && enforcedAddedComponentFailures.size > 0;
+
+    const isPassed = failures.size === 0 && !hasEnforcedAddedComponentFailures;
     if (isPassed) {
         logSuccess('All files pass React Compiler compliance check!');
         return;
@@ -709,20 +651,39 @@ function printResults({success, failures, suppressedFailures}: CompilerResults,
 
     const distinctFileNames = new Set<string>();
     // eslint-disable-next-line unicorn/no-array-for-each
-    failures.forEach((failure) => {
+    for (const failure of failures.values()) {
         distinctFileNames.add(failure.file);
-    });
+    }
 
     log();
     logError(`Failed to compile ${distinctFileNames.size} files with React Compiler:`);
     log();
 
-    // eslint-disable-next-line unicorn/no-array-for-each
-    filteredFailures.forEach((failure) => {
-        const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
-        logBold(`${failure.file}${location}`);
-        logNote(`${TAB}${failure.reason ?? 'No reason provided'}`);
-    });
+    function printFailures(failuresToPrint: FailureMap, level = 0) {
+        for (const failure of failuresToPrint.values()) {
+            const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
+            logBold(`${TAB.repeat(level)}${failure.file}${location}`);
+            logNote(`${TAB.repeat(level + 1)}${failure.reason ?? 'No reason provided'}`);
+        }
+    }
+
+    printFailures(failures);
+
+    log();
+    logError(`These newly added component files were enforced to be automatically memoized with React Compiler:`);
+    log();
+
+    if (hasEnforcedAddedComponentFailures) {
+        for (const [filePath, {message, compilerFailures}] of enforcedAddedComponentFailures.entries()) {
+            logBold(`${filePath}:`);
+            logNote(`${TAB}${message}`);
+
+            if (compilerFailures) {
+                logNote(`${TAB}Additional failures:`);
+                printFailures(compilerFailures, 1);
+            }
+        }
+    }
 
     log();
     logError('The files above failed to compile with React Compiler, probably because of Rules of React violations. Please fix the issues and run the check again.');

From 0380a131a375e2163b4bfcb782700761e29f70dc Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 14:22:06 +0100
Subject: [PATCH 05/45] refactor: move around functions

---
 scripts/react-compiler-compliance-check.ts | 226 +++++++++++----------
 1 file changed, 116 insertions(+), 110 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 13cc1816c6e2a..5f59329426d36 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -45,7 +45,8 @@ const MANUAL_MEMOIZATION_PATTERNS: ManualMemoizationPattern[] = [
     },
 ];
 
-const MANUAL_MEMOIZATION_FAILURE_MESSAGE = `Manual memoization is not allowed in new React component files. Please remove any manual memoization functions (\`useMemo\`, \`useCallback\`, \`memo\`) or use the \`"use no memo"\` directive at the beginning of the component.`;
+const MANUAL_MEMOIZATION_FAILURE_MESSAGE =
+    'Manual memoization is not allowed in new React component files. Please remove any manual memoization functions (`useMemo`, `useCallback`, `memo`) or use the `"use no memo"` directive at the beginning of the component.';
 
 const NO_MANUAL_MEMO_DIRECTIVE_PATTERN = /["']use no memo["']\s*;?/;
 
@@ -324,115 +325,6 @@ function createFilesGlob(files?: string[]): string | undefined {
     return `**/+(${files.join('|')})`;
 }
 
-function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffResult) {
-    const addedDiffFiles = new Set<string>();
-    for (const file of diffResult.files) {
-        if (Git.isAddedDiffFile(file)) {
-            addedDiffFiles.add(file.filePath);
-        }
-    }
-
-    const nonAutoMemoEnforcedFailures: FailureMap = new Map();
-    const addedFileFailures = new Map<string, FailureMap>();
-    for (const [failureKey, failure] of failures) {
-        const addedFilePath = failure.file;
-
-        if (!addedDiffFiles.has(addedFilePath)) {
-            nonAutoMemoEnforcedFailures.set(failureKey, failure);
-            continue;
-        }
-
-        if (addedFileFailures.has(addedFilePath)) {
-            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-            const existingAddedFileFailuresMap = addedFileFailures.get(addedFilePath)!;
-            existingAddedFileFailuresMap.set(failureKey, failure);
-        }
-
-        addedFileFailures.set(addedFilePath, new Map<string, CompilerFailure>([[failureKey, failure]]));
-    }
-
-    function addNonAutoMemoEnforcedFailures(addedFilePath: string): void {
-        const addedFileFailuresMap = addedFileFailures.get(addedFilePath);
-
-        if (!addedFileFailuresMap) {
-            return;
-        }
-
-        for (const [failureKey, failure] of failures) {
-            nonAutoMemoEnforcedFailures.set(failureKey, failure);
-        }
-    }
-
-    const addedComponentFailures: EnforcedAddedComponentFailureMap = new Map();
-    for (const addedFilePath of addedDiffFiles) {
-        const source = readSourceFile(addedFilePath);
-        if (!source || hasManualMemoOptOutDirective(source)) {
-            addNonAutoMemoEnforcedFailures(addedFilePath);
-            continue;
-        }
-
-        const manualMemoMatches = findManualMemoizationMatches(source);
-        if (manualMemoMatches.length === 0) {
-            addNonAutoMemoEnforcedFailures(addedFilePath);
-            continue;
-        }
-
-        const manualMemoFailure: ManualMemoFailure = {
-            message: MANUAL_MEMOIZATION_FAILURE_MESSAGE,
-            compilerFailures: addedFileFailures.get(addedFilePath),
-        };
-        addedComponentFailures.set(addedFilePath, manualMemoFailure);
-    }
-
-    return {
-        nonAutoMemoEnforcedFailures,
-        addedComponentFailures,
-    };
-}
-
-function hasManualMemoOptOutDirective(source: string): boolean {
-    return NO_MANUAL_MEMO_DIRECTIVE_PATTERN.test(source);
-}
-
-function findManualMemoizationMatches(source: string): ManualMemoizationMatch[] {
-    const matches: ManualMemoizationMatch[] = [];
-
-    for (const pattern of MANUAL_MEMOIZATION_PATTERNS) {
-        pattern.regex.lastIndex = 0;
-        let regexMatch: RegExpExecArray | null;
-        // eslint-disable-next-line no-cond-assign
-        while ((regexMatch = pattern.regex.exec(source)) !== null) {
-            const matchIndex = regexMatch.index;
-            const {line, column} = getLineAndColumnFromIndex(source, matchIndex);
-            matches.push({
-                keyword: pattern.keyword,
-                line,
-                column,
-            });
-        }
-    }
-
-    return matches;
-}
-
-function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
-    const substring = source.slice(0, index);
-    const line = substring.split('\n').length;
-    const lastLineBreakIndex = substring.lastIndexOf('\n');
-    const column = lastLineBreakIndex === -1 ? index + 1 : index - lastLineBreakIndex;
-    return {line, column};
-}
-
-function readSourceFile(filePath: string): string | null {
-    try {
-        const absolutePath = join(process.cwd(), filePath);
-        return readFileSync(absolutePath, 'utf8');
-    } catch (error) {
-        logWarn(`Unable to read ${filePath} while enforcing new component rules.`, error);
-        return null;
-    }
-}
-
 /**
  * Filters compiler results to only include failures for lines that were changed in the git diff.
  * This helps focus on new issues introduced by the current changes rather than pre-existing issues.
@@ -595,6 +487,120 @@ async function filterResultsByDiff(
     };
 }
 
+function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffResult) {
+    const addedDiffFiles = new Set<string>();
+    for (const file of diffResult.files) {
+        if (Git.isAddedDiffFile(file)) {
+            addedDiffFiles.add(file.filePath);
+        }
+    }
+
+    // Partition failures into non-auto memo enforced failures and added file failures
+    const nonAutoMemoEnforcedFailures: FailureMap = new Map();
+    const addedFileFailures = new Map<string, FailureMap>();
+    for (const [failureKey, failure] of failures) {
+        const addedFilePath = failure.file;
+
+        if (!addedDiffFiles.has(addedFilePath)) {
+            nonAutoMemoEnforcedFailures.set(failureKey, failure);
+            continue;
+        }
+
+        if (addedFileFailures.has(addedFilePath)) {
+            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+            const existingAddedFileFailuresMap = addedFileFailures.get(addedFilePath)!;
+            existingAddedFileFailuresMap.set(failureKey, failure);
+        }
+
+        addedFileFailures.set(addedFilePath, new Map<string, CompilerFailure>([[failureKey, failure]]));
+    }
+
+    // Used as fallback to add back the failures from added files that didn't have manual memoization
+    function addNonAutoMemoEnforcedFailures(addedFilePath: string): void {
+        const addedFileFailuresMap = addedFileFailures.get(addedFilePath);
+
+        if (!addedFileFailuresMap) {
+            return;
+        }
+
+        for (const [failureKey, failure] of failures) {
+            nonAutoMemoEnforcedFailures.set(failureKey, failure);
+        }
+    }
+
+    const addedComponentFailures: EnforcedAddedComponentFailureMap = new Map();
+    for (const addedFilePath of addedDiffFiles) {
+        const source = readSourceFile(addedFilePath);
+        if (!source || hasManualMemoOptOutDirective(source)) {
+            addNonAutoMemoEnforcedFailures(addedFilePath);
+            continue;
+        }
+
+        const manualMemoMatches = findManualMemoizationMatches(source);
+
+        console.log('manualMemoMatches', manualMemoMatches);
+
+        if (manualMemoMatches.length === 0) {
+            addNonAutoMemoEnforcedFailures(addedFilePath);
+            continue;
+        }
+
+        const manualMemoFailure: ManualMemoFailure = {
+            message: MANUAL_MEMOIZATION_FAILURE_MESSAGE,
+            compilerFailures: addedFileFailures.get(addedFilePath),
+        };
+        addedComponentFailures.set(addedFilePath, manualMemoFailure);
+    }
+
+    return {
+        nonAutoMemoEnforcedFailures,
+        addedComponentFailures,
+    };
+}
+
+function hasManualMemoOptOutDirective(source: string): boolean {
+    return NO_MANUAL_MEMO_DIRECTIVE_PATTERN.test(source);
+}
+
+function findManualMemoizationMatches(source: string): ManualMemoizationMatch[] {
+    const matches: ManualMemoizationMatch[] = [];
+
+    for (const pattern of MANUAL_MEMOIZATION_PATTERNS) {
+        pattern.regex.lastIndex = 0;
+        let regexMatch: RegExpExecArray | null;
+        // eslint-disable-next-line no-cond-assign
+        while ((regexMatch = pattern.regex.exec(source)) !== null) {
+            const matchIndex = regexMatch.index;
+            const {line, column} = getLineAndColumnFromIndex(source, matchIndex);
+            matches.push({
+                keyword: pattern.keyword,
+                line,
+                column,
+            });
+        }
+    }
+
+    return matches;
+}
+
+function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
+    const substring = source.slice(0, index);
+    const line = substring.split('\n').length;
+    const lastLineBreakIndex = substring.lastIndexOf('\n');
+    const column = lastLineBreakIndex === -1 ? index + 1 : index - lastLineBreakIndex;
+    return {line, column};
+}
+
+function readSourceFile(filePath: string): string | null {
+    try {
+        const absolutePath = join(process.cwd(), filePath);
+        return readFileSync(absolutePath, 'utf8');
+    } catch (error) {
+        logWarn(`Unable to read ${filePath} while enforcing new component rules.`, error);
+        return null;
+    }
+}
+
 function printResults(
     {success, failures, suppressedFailures, enforcedAddedComponentFailures}: CompilerResults,
     {shouldPrintSuccesses, shouldPrintSuppressedErrors}: PrintResultsOptions,

From e503e0ecf4639bed0b9d5d54ee627cfbba89b1e0 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 14:32:54 +0100
Subject: [PATCH 06/45] only print failures if there are any

---
 scripts/react-compiler-compliance-check.ts | 30 ++++++++++++----------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 5f59329426d36..39d9123a19863 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -655,16 +655,6 @@ function printResults(
         return;
     }
 
-    const distinctFileNames = new Set<string>();
-    // eslint-disable-next-line unicorn/no-array-for-each
-    for (const failure of failures.values()) {
-        distinctFileNames.add(failure.file);
-    }
-
-    log();
-    logError(`Failed to compile ${distinctFileNames.size} files with React Compiler:`);
-    log();
-
     function printFailures(failuresToPrint: FailureMap, level = 0) {
         for (const failure of failuresToPrint.values()) {
             const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
@@ -673,13 +663,25 @@ function printResults(
         }
     }
 
-    printFailures(failures);
+    const distinctFileNames = new Set<string>();
+    // eslint-disable-next-line unicorn/no-array-for-each
+    for (const failure of failures.values()) {
+        distinctFileNames.add(failure.file);
+    }
 
-    log();
-    logError(`These newly added component files were enforced to be automatically memoized with React Compiler:`);
-    log();
+    if (distinctFileNames.size > 0) {
+        log();
+        logError(`Failed to compile ${distinctFileNames.size} files with React Compiler:`);
+        log();
+
+        printFailures(failures);
+    }
 
     if (hasEnforcedAddedComponentFailures) {
+        log();
+        logError(`These newly added component files were enforced to be automatically memoized with React Compiler:`);
+        log();
+
         for (const [filePath, {message, compilerFailures}] of enforcedAddedComponentFailures.entries()) {
             logBold(`${filePath}:`);
             logNote(`${TAB}${message}`);

From 47d2d5a00e3c4b481b8ba559405012cf81c8bd3d Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 14:33:07 +0100
Subject: [PATCH 07/45] refactor: no condition assignment

---
 scripts/react-compiler-compliance-check.ts | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 39d9123a19863..cf8e372b81389 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -565,18 +565,14 @@ function hasManualMemoOptOutDirective(source: string): boolean {
 function findManualMemoizationMatches(source: string): ManualMemoizationMatch[] {
     const matches: ManualMemoizationMatch[] = [];
 
+    let regexMatch: RegExpExecArray | null;
     for (const pattern of MANUAL_MEMOIZATION_PATTERNS) {
         pattern.regex.lastIndex = 0;
-        let regexMatch: RegExpExecArray | null;
-        // eslint-disable-next-line no-cond-assign
-        while ((regexMatch = pattern.regex.exec(source)) !== null) {
+        regexMatch = pattern.regex.exec(source);
+        if (regexMatch) {
             const matchIndex = regexMatch.index;
             const {line, column} = getLineAndColumnFromIndex(source, matchIndex);
-            matches.push({
-                keyword: pattern.keyword,
-                line,
-                column,
-            });
+            matches.push({keyword: pattern.keyword, line, column});
         }
     }
 

From 3bb4e04332d34d4a969e4beca9ed5ff21b93576e Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 14:33:24 +0100
Subject: [PATCH 08/45] store manual memo matches

---
 scripts/react-compiler-compliance-check.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index cf8e372b81389..653cdc5e1356d 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -83,6 +83,7 @@ type EnforcedAddedComponentFailureMap = Map<string, ManualMemoFailure>;
 
 type ManualMemoFailure = {
     message: string;
+    manualMemoizationMatches: ManualMemoizationMatch[];
     compilerFailures: FailureMap | undefined;
 };
 
@@ -536,17 +537,18 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
             continue;
         }
 
-        const manualMemoMatches = findManualMemoizationMatches(source);
+        const manualMemoizationMatches = findManualMemoizationMatches(source);
 
         console.log('manualMemoMatches', manualMemoMatches);
 
-        if (manualMemoMatches.length === 0) {
+        if (manualMemoizationMatches.length === 0) {
             addNonAutoMemoEnforcedFailures(addedFilePath);
             continue;
         }
 
         const manualMemoFailure: ManualMemoFailure = {
             message: MANUAL_MEMOIZATION_FAILURE_MESSAGE,
+            manualMemoizationMatches,
             compilerFailures: addedFileFailures.get(addedFilePath),
         };
         addedComponentFailures.set(addedFilePath, manualMemoFailure);

From a98620e1d60121739a4c656f298d5f84060e1e01 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 15:19:57 +0100
Subject: [PATCH 09/45] fix: `isAddedFile` util not working correctly

---
 scripts/utils/Git.ts | 24 ++++--------------------
 1 file changed, 4 insertions(+), 20 deletions(-)

diff --git a/scripts/utils/Git.ts b/scripts/utils/Git.ts
index ce1a5ea94bf07..3c21241deba03 100644
--- a/scripts/utils/Git.ts
+++ b/scripts/utils/Git.ts
@@ -289,31 +289,15 @@ class Git {
         const hasModifiedLines = file.modifiedLines.size > 0;
         const hasRemovedLines = file.removedLines.size > 0;
 
-        if (!hasAddedLines) {
+        if (!hasAddedLines || hasModifiedLines || hasRemovedLines) {
             return false;
         }
 
-        const hasOnlyAdditions = !hasModifiedLines && !hasRemovedLines;
-        return hasOnlyAdditions;
-    }
-
-    /**
-     * Check if a file from a Git diff is removed.
-     *
-     * @param file - The file to check
-     * @returns true if the file is removed, false otherwise
-     */
-    static isRemovedDiffFile(file: FileDiff): boolean {
-        const hasRemovedLines = file.removedLines.size > 0;
-        const hasModifiedLines = file.modifiedLines.size > 0;
-        const hasAddedLines = file.addedLines.size > 0;
-
-        if (!hasRemovedLines) {
-            return false;
+        if (file.hunks.length === 1 && file.hunks.at(0)!.oldStart === 0) {
+            return true;
         }
 
-        const hasOnlyRemovals = !hasModifiedLines && !hasAddedLines;
-        return hasOnlyRemovals;
+        return false;
     }
 
     /**

From 738e50bcd960ecd073820127f799011b7b864776 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 15:26:47 +0100
Subject: [PATCH 10/45] Create RCAutoMemoComponent.tsx

---
 src/components/RCAutoMemoComponent.tsx | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 src/components/RCAutoMemoComponent.tsx

diff --git a/src/components/RCAutoMemoComponent.tsx b/src/components/RCAutoMemoComponent.tsx
new file mode 100644
index 0000000000000..070f8441093e2
--- /dev/null
+++ b/src/components/RCAutoMemoComponent.tsx
@@ -0,0 +1,11 @@
+import {useMemo} from 'react';
+
+function RCAutoMemoComponent() {
+    const someValue = useMemo(() => {
+        return 'someValue';
+    }, []);
+
+    return <div>{someValue}</div>;
+}
+
+export default RCAutoMemoComponent;

From 8795d767562fabceb9047136a88657d64fd70994 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 15:29:51 +0100
Subject: [PATCH 11/45] fix: print manual memo usages individually

---
 scripts/react-compiler-compliance-check.ts | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 653cdc5e1356d..b0171c354b91e 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -82,7 +82,6 @@ type CompilerFailure = {
 type EnforcedAddedComponentFailureMap = Map<string, ManualMemoFailure>;
 
 type ManualMemoFailure = {
-    message: string;
     manualMemoizationMatches: ManualMemoizationMatch[];
     compilerFailures: FailureMap | undefined;
 };
@@ -532,22 +531,19 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
     const addedComponentFailures: EnforcedAddedComponentFailureMap = new Map();
     for (const addedFilePath of addedDiffFiles) {
         const source = readSourceFile(addedFilePath);
-        if (!source || hasManualMemoOptOutDirective(source)) {
+        if (!source || NO_MANUAL_MEMO_DIRECTIVE_PATTERN.test(source)) {
             addNonAutoMemoEnforcedFailures(addedFilePath);
             continue;
         }
 
         const manualMemoizationMatches = findManualMemoizationMatches(source);
 
-        console.log('manualMemoMatches', manualMemoMatches);
-
         if (manualMemoizationMatches.length === 0) {
             addNonAutoMemoEnforcedFailures(addedFilePath);
             continue;
         }
 
         const manualMemoFailure: ManualMemoFailure = {
-            message: MANUAL_MEMOIZATION_FAILURE_MESSAGE,
             manualMemoizationMatches,
             compilerFailures: addedFileFailures.get(addedFilePath),
         };
@@ -560,10 +556,6 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
     };
 }
 
-function hasManualMemoOptOutDirective(source: string): boolean {
-    return NO_MANUAL_MEMO_DIRECTIVE_PATTERN.test(source);
-}
-
 function findManualMemoizationMatches(source: string): ManualMemoizationMatch[] {
     const matches: ManualMemoizationMatch[] = [];
 
@@ -680,12 +672,16 @@ function printResults(
         logError(`These newly added component files were enforced to be automatically memoized with React Compiler:`);
         log();
 
-        for (const [filePath, {message, compilerFailures}] of enforcedAddedComponentFailures.entries()) {
-            logBold(`${filePath}:`);
-            logNote(`${TAB}${message}`);
+        for (const [filePath, {manualMemoizationMatches, compilerFailures}] of enforcedAddedComponentFailures.entries()) {
+            for (const manualMemoizationMatch of manualMemoizationMatches) {
+                const location = manualMemoizationMatch.line && manualMemoizationMatch.column ? `:${manualMemoizationMatch.line}:${manualMemoizationMatch.column}` : '';
+                logBold(`${filePath}${location}`);
+                logNote(`${TAB}${MANUAL_MEMOIZATION_FAILURE_MESSAGE}`);
+            }
 
             if (compilerFailures) {
-                logNote(`${TAB}Additional failures:`);
+                log();
+                logBold(`${TAB}Additional React Compiler errors:`);
                 printFailures(compilerFailures, 1);
             }
         }

From 52714ec5960f29ca5f9b4ed6691e20054e505575 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 15:30:30 +0100
Subject: [PATCH 12/45] fix: no memo message

---
 scripts/react-compiler-compliance-check.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index b0171c354b91e..b633bb339ad59 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -46,7 +46,7 @@ const MANUAL_MEMOIZATION_PATTERNS: ManualMemoizationPattern[] = [
 ];
 
 const MANUAL_MEMOIZATION_FAILURE_MESSAGE =
-    'Manual memoization is not allowed in new React component files. Please remove any manual memoization functions (`useMemo`, `useCallback`, `memo`) or use the `"use no memo"` directive at the beginning of the component.';
+    'Manual memoization is not allowed in new React component files. Please remove any manual memoization functions (`useMemo`, `useCallback`, `memo`) or use the `"use no memo";` directive at the beginning of the component.';
 
 const NO_MANUAL_MEMO_DIRECTIVE_PATTERN = /["']use no memo["']\s*;?/;
 

From 3604b752d49a62ccbbdf6e232b8a51dce9ba2a60 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 17:55:50 +0100
Subject: [PATCH 13/45] fix: update manual memo message and log specific manual
 memo keyword

---
 scripts/react-compiler-compliance-check.ts | 59 +++++++++-------------
 1 file changed, 24 insertions(+), 35 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index b633bb339ad59..71bc9706cdf97 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -25,28 +25,16 @@ const SUPPRESSED_COMPILER_ERRORS = [
     '(BuildHIR::lowerExpression) Expected Identifier, got MemberExpression key in ObjectExpression',
 ] as const satisfies string[];
 
-type ManualMemoizationPattern = {
-    keyword: string;
-    regex: RegExp;
-};
+const MANUAL_MEMOIZATION_PATTERNS = {
+    memo: /\b(?:React\.)?memo\s*\(/g,
+    useMemo: /\b(?:React\.)?useMemo\s*\(/g,
+    useCallback: /\b(?:React\.)?useCallback\s*\(/g,
+} as const satisfies Record<string, RegExp>;
+
+type ManualMemoizationKeyword = keyof typeof MANUAL_MEMOIZATION_PATTERNS;
 
-const MANUAL_MEMOIZATION_PATTERNS: ManualMemoizationPattern[] = [
-    {
-        keyword: 'memo',
-        regex: /\b(?:React\.)?memo\s*\(/g,
-    },
-    {
-        keyword: 'useMemo',
-        regex: /\b(?:React\.)?useMemo\s*\(/g,
-    },
-    {
-        keyword: 'useCallback',
-        regex: /\b(?:React\.)?useCallback\s*\(/g,
-    },
-];
-
-const MANUAL_MEMOIZATION_FAILURE_MESSAGE =
-    'Manual memoization is not allowed in new React component files. Please remove any manual memoization functions (`useMemo`, `useCallback`, `memo`) or use the `"use no memo";` directive at the beginning of the component.';
+const MANUAL_MEMOIZATION_FAILURE_MESSAGE = (manualMemoizationKeyword: ManualMemoizationKeyword) =>
+    `Found a manual memoization usage of ${manualMemoizationKeyword}. Newly added React component files must not contain any manual memoization and instead be auto-memoized by React Compiler. Remove ${manualMemoizationKeyword} or disable automatic memoization by adding the \`"use no memo";\` directive at the beginning of the component and give a reason why automatic memoization is not applicable.`;
 
 const NO_MANUAL_MEMO_DIRECTIVE_PATTERN = /["']use no memo["']\s*;?/;
 
@@ -87,7 +75,7 @@ type ManualMemoFailure = {
 };
 
 type ManualMemoizationMatch = {
-    keyword: string;
+    keyword: ManualMemoizationKeyword;
     line: number;
     column: number;
 };
@@ -560,13 +548,14 @@ function findManualMemoizationMatches(source: string): ManualMemoizationMatch[]
     const matches: ManualMemoizationMatch[] = [];
 
     let regexMatch: RegExpExecArray | null;
-    for (const pattern of MANUAL_MEMOIZATION_PATTERNS) {
-        pattern.regex.lastIndex = 0;
-        regexMatch = pattern.regex.exec(source);
+    for (const keyword of Object.keys(MANUAL_MEMOIZATION_PATTERNS) as ManualMemoizationKeyword[]) {
+        const regex = MANUAL_MEMOIZATION_PATTERNS[keyword];
+        regex.lastIndex = 0;
+        regexMatch = regex.exec(source);
         if (regexMatch) {
             const matchIndex = regexMatch.index;
             const {line, column} = getLineAndColumnFromIndex(source, matchIndex);
-            matches.push({keyword: pattern.keyword, line, column});
+            matches.push({keyword, line, column});
         }
     }
 
@@ -645,14 +634,6 @@ function printResults(
         return;
     }
 
-    function printFailures(failuresToPrint: FailureMap, level = 0) {
-        for (const failure of failuresToPrint.values()) {
-            const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
-            logBold(`${TAB.repeat(level)}${failure.file}${location}`);
-            logNote(`${TAB.repeat(level + 1)}${failure.reason ?? 'No reason provided'}`);
-        }
-    }
-
     const distinctFileNames = new Set<string>();
     // eslint-disable-next-line unicorn/no-array-for-each
     for (const failure of failures.values()) {
@@ -676,7 +657,7 @@ function printResults(
             for (const manualMemoizationMatch of manualMemoizationMatches) {
                 const location = manualMemoizationMatch.line && manualMemoizationMatch.column ? `:${manualMemoizationMatch.line}:${manualMemoizationMatch.column}` : '';
                 logBold(`${filePath}${location}`);
-                logNote(`${TAB}${MANUAL_MEMOIZATION_FAILURE_MESSAGE}`);
+                logNote(`${TAB}${MANUAL_MEMOIZATION_FAILURE_MESSAGE(manualMemoizationMatch.keyword)}`);
             }
 
             if (compilerFailures) {
@@ -691,6 +672,14 @@ function printResults(
     logError('The files above failed to compile with React Compiler, probably because of Rules of React violations. Please fix the issues and run the check again.');
 }
 
+function printFailures(failuresToPrint: FailureMap, level = 0) {
+    for (const failure of failuresToPrint.values()) {
+        const location = failure.line && failure.column ? `:${failure.line}:${failure.column}` : '';
+        logBold(`${TAB.repeat(level)}${failure.file}${location}`);
+        logNote(`${TAB.repeat(level + 1)}${failure.reason ?? 'No reason provided'}`);
+    }
+}
+
 function generateReport(results: CompilerResults, outputFileName = DEFAULT_REPORT_FILENAME): void {
     log('\n');
     logInfo('Creating React Compiler Compliance Check report:');

From 1842f671f258b135dc1d328eceb94f615badd852 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 17:58:23 +0100
Subject: [PATCH 14/45] feat: enable auto-memo enforcement in workflow

---
 .github/workflows/react-compiler-compliance.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/react-compiler-compliance.yml b/.github/workflows/react-compiler-compliance.yml
index e8900a6ed6344..8df910f0b2597 100644
--- a/.github/workflows/react-compiler-compliance.yml
+++ b/.github/workflows/react-compiler-compliance.yml
@@ -28,7 +28,7 @@ jobs:
         # In phase 0 of the React Compiler compliance check rollout,
         # we want to report failures but don't fail the check.
         # See https://github.com/Expensify/App/issues/68765#issuecomment-3487317881
-        run: npm run react-compiler-compliance-check check-changed || true
+        run: npm run react-compiler-compliance-check check-changed --enforce-new-components || true
         env:
           CI: true
           GITHUB_TOKEN: ${{ github.token }}

From 644d4d98ff02acbd9756a355ef1f7228793bc880 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 17:58:27 +0100
Subject: [PATCH 15/45] Update RCAutoMemoComponent.tsx

---
 src/components/RCAutoMemoComponent.tsx | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/components/RCAutoMemoComponent.tsx b/src/components/RCAutoMemoComponent.tsx
index 070f8441093e2..f6a7af9ad8135 100644
--- a/src/components/RCAutoMemoComponent.tsx
+++ b/src/components/RCAutoMemoComponent.tsx
@@ -1,11 +1,16 @@
-import {useMemo} from 'react';
+import {useCallback, useMemo} from 'react';
+import {Pressable} from 'react-native';
 
 function RCAutoMemoComponent() {
     const someValue = useMemo(() => {
         return 'someValue';
     }, []);
 
-    return <div>{someValue}</div>;
+    const someCallback = useCallback(() => {
+        return 'someValue';
+    }, []);
+
+    return <Pressable onPress={someCallback}>{someValue}</Pressable>;
 }
 
 export default RCAutoMemoComponent;

From f49d6f6e34402540e12a0c65ab617b205fc14e7a Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:00:17 +0100
Subject: [PATCH 16/45] fix: invalid check flag

---
 .github/workflows/react-compiler-compliance.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/react-compiler-compliance.yml b/.github/workflows/react-compiler-compliance.yml
index 8df910f0b2597..6e419beec172e 100644
--- a/.github/workflows/react-compiler-compliance.yml
+++ b/.github/workflows/react-compiler-compliance.yml
@@ -28,7 +28,7 @@ jobs:
         # In phase 0 of the React Compiler compliance check rollout,
         # we want to report failures but don't fail the check.
         # See https://github.com/Expensify/App/issues/68765#issuecomment-3487317881
-        run: npm run react-compiler-compliance-check check-changed --enforce-new-components || true
+        run: npm run react-compiler-compliance-check check-changed --enforceNewComponents || true
         env:
           CI: true
           GITHUB_TOKEN: ${{ github.token }}

From 6e5496b95a362a08ba16a13feffe368f486f3002 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:04:14 +0100
Subject: [PATCH 17/45] Update RCAutoMemoComponent.tsx

---
 src/components/RCAutoMemoComponent.tsx | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/components/RCAutoMemoComponent.tsx b/src/components/RCAutoMemoComponent.tsx
index f6a7af9ad8135..abaebfcca7e01 100644
--- a/src/components/RCAutoMemoComponent.tsx
+++ b/src/components/RCAutoMemoComponent.tsx
@@ -10,6 +10,7 @@ function RCAutoMemoComponent() {
         return 'someValue';
     }, []);
 
+    // eslint-disable-next-line react-native-a11y/has-valid-accessibility-descriptors
     return <Pressable onPress={someCallback}>{someValue}</Pressable>;
 }
 

From 01d84d6dcfb24825ba9e8c2679a9578ffe699f75 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:04:19 +0100
Subject: [PATCH 18/45] fix: TS errors

---
 scripts/utils/Git.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/utils/Git.ts b/scripts/utils/Git.ts
index 3c21241deba03..8c7f15ee106d7 100644
--- a/scripts/utils/Git.ts
+++ b/scripts/utils/Git.ts
@@ -293,7 +293,7 @@ class Git {
             return false;
         }
 
-        if (file.hunks.length === 1 && file.hunks.at(0)!.oldStart === 0) {
+        if (file.hunks.length === 1 && file.hunks.at(0)?.oldStart === 0) {
             return true;
         }
 

From 951b21b67b49517ab027cd77337ae28b13c0c497 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:06:27 +0100
Subject: [PATCH 19/45] add logs

---
 scripts/react-compiler-compliance-check.ts | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 71bc9706cdf97..58805f6f12347 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -483,6 +483,9 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
         }
     }
 
+    console.log(addedDiffFiles);
+    console.log(diffResult);
+
     // Partition failures into non-auto memo enforced failures and added file failures
     const nonAutoMemoEnforcedFailures: FailureMap = new Map();
     const addedFileFailures = new Map<string, FailureMap>();
@@ -526,6 +529,8 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
 
         const manualMemoizationMatches = findManualMemoizationMatches(source);
 
+        console.log(manualMemoizationMatches);
+
         if (manualMemoizationMatches.length === 0) {
             addNonAutoMemoEnforcedFailures(addedFilePath);
             continue;

From 5ad1b132c8d5be2ea679f026e24d7b30ede764f3 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:11:18 +0100
Subject: [PATCH 20/45] add log

---
 scripts/react-compiler-compliance-check.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 58805f6f12347..119850822778e 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -118,11 +118,12 @@ async function check({
         logInfo('Running React Compiler check for all files...');
     }
 
-    const shouldComputeDiff = shouldFilterByDiff || shouldEnforceNewComponents;
+    console.log(shouldEnforceNewComponents);
+
     const src = createFilesGlob(files);
     let results = runCompilerHealthcheck(src);
 
-    if (shouldComputeDiff) {
+    if (shouldFilterByDiff || shouldEnforceNewComponents) {
         const mainBaseCommitHash = await Git.getMainBranchCommitHash(remote);
         const diffFilteringCommits: DiffFilteringCommits = {fromRef: mainBaseCommitHash};
         const diffResult = Git.diff(diffFilteringCommits.fromRef, diffFilteringCommits.toRef);

From 83313ac759057d6f49f1cf4d17bf00077562b4a9 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:19:22 +0100
Subject: [PATCH 21/45] fix: NPM script params need to be properly forwarded

---
 .github/workflows/react-compiler-compliance.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/react-compiler-compliance.yml b/.github/workflows/react-compiler-compliance.yml
index 6e419beec172e..9c067268dee42 100644
--- a/.github/workflows/react-compiler-compliance.yml
+++ b/.github/workflows/react-compiler-compliance.yml
@@ -28,7 +28,7 @@ jobs:
         # In phase 0 of the React Compiler compliance check rollout,
         # we want to report failures but don't fail the check.
         # See https://github.com/Expensify/App/issues/68765#issuecomment-3487317881
-        run: npm run react-compiler-compliance-check check-changed --enforceNewComponents || true
+        run: npm run react-compiler-compliance-check check-changed -- --enforceNewComponents || true
         env:
           CI: true
           GITHUB_TOKEN: ${{ github.token }}

From 891fd33f72c1c94955f8a855534828da1b7cb067 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:22:06 +0100
Subject: [PATCH 22/45] chore: change workflow so that it can fail

---
 .github/workflows/react-compiler-compliance.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/react-compiler-compliance.yml b/.github/workflows/react-compiler-compliance.yml
index 9c067268dee42..e67c2a694de37 100644
--- a/.github/workflows/react-compiler-compliance.yml
+++ b/.github/workflows/react-compiler-compliance.yml
@@ -28,7 +28,7 @@ jobs:
         # In phase 0 of the React Compiler compliance check rollout,
         # we want to report failures but don't fail the check.
         # See https://github.com/Expensify/App/issues/68765#issuecomment-3487317881
-        run: npm run react-compiler-compliance-check check-changed -- --enforceNewComponents || true
+        run: npm run react-compiler-compliance-check check-changed -- --enforceNewComponents
         env:
           CI: true
           GITHUB_TOKEN: ${{ github.token }}

From c8cbd30e41eab3ceac5a366e515f9a81a7e2dd7f Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:23:31 +0100
Subject: [PATCH 23/45] remove logs

---
 scripts/react-compiler-compliance-check.ts | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 119850822778e..8b8592694cb6a 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -118,8 +118,6 @@ async function check({
         logInfo('Running React Compiler check for all files...');
     }
 
-    console.log(shouldEnforceNewComponents);
-
     const src = createFilesGlob(files);
     let results = runCompilerHealthcheck(src);
 
@@ -484,9 +482,6 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
         }
     }
 
-    console.log(addedDiffFiles);
-    console.log(diffResult);
-
     // Partition failures into non-auto memo enforced failures and added file failures
     const nonAutoMemoEnforcedFailures: FailureMap = new Map();
     const addedFileFailures = new Map<string, FailureMap>();

From 3443b120c0e7410268002abc9e3da03a2803ad4e Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:23:49 +0100
Subject: [PATCH 24/45] remove log

---
 scripts/react-compiler-compliance-check.ts | 2 --
 1 file changed, 2 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 8b8592694cb6a..ac78915a93064 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -525,8 +525,6 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
 
         const manualMemoizationMatches = findManualMemoizationMatches(source);
 
-        console.log(manualMemoizationMatches);
-
         if (manualMemoizationMatches.length === 0) {
             addNonAutoMemoEnforcedFailures(addedFilePath);
             continue;

From a7157e5955863099ea9f2a30334aa4124529b0bd Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:28:07 +0100
Subject: [PATCH 25/45] docs: add JSDoc comments

---
 scripts/react-compiler-compliance-check.ts | 49 +++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index ac78915a93064..1d9e7b60f8e6e 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -198,6 +198,11 @@ function addFailureIfDoesNotExist(failureMap: FailureMap, newFailure: CompilerFa
     return true;
 }
 
+/**
+ * Parses the output of the react-compiler-healthcheck command and returns the compiler results.
+ * @param output - The output of the react-compiler-healthcheck command
+ * @returns The compiler results
+ */
 function parseHealthcheckOutput(output: string): CompilerResults {
     const lines = output.split('\n');
 
@@ -284,6 +289,11 @@ function parseHealthcheckOutput(output: string): CompilerResults {
     return results;
 }
 
+/**
+ * Checks if a compiler error should be suppressed based on the error reason.
+ * @param reason - The reason for the compiler error
+ * @returns True if the error should be suppressed, false otherwise
+ */
 function shouldSuppressCompilerError(reason: string | undefined): boolean {
     if (!reason) {
         return false;
@@ -293,6 +303,11 @@ function shouldSuppressCompilerError(reason: string | undefined): boolean {
     return SUPPRESSED_COMPILER_ERRORS.some((suppressedError) => reason.includes(suppressedError));
 }
 
+/**
+ * Creates a unique key for a compiler failure by combining the file path, line number, and column number.
+ * @param failure - The compiler failure to create a unique key for
+ * @returns A unique key for the compiler failure
+ */
 function getUniqueFileKey({file, line, column}: CompilerFailure): string {
     const isLineSet = line !== undefined;
     const isLineAndColumnSet = isLineSet && column !== undefined;
@@ -300,6 +315,11 @@ function getUniqueFileKey({file, line, column}: CompilerFailure): string {
     return file + (isLineSet ? `:${line}` : '') + (isLineAndColumnSet ? `:${column}` : '');
 }
 
+/**
+ * Creates a glob pattern from an array of file paths.
+ * @param files - The file paths to create a glob pattern from
+ * @returns A glob pattern string
+ */
 function createFilesGlob(files?: string[]): string | undefined {
     if (!files || files.length === 0) {
         return undefined;
@@ -392,7 +412,11 @@ async function filterResultsByDiff(
         }
     }
 
-    // Filter failures to only include those on changed lines and files/chunks for which an eslint-disable comment is was removed
+    /**
+     * Filter failures to only include those on changed lines and files/chunks for which an eslint-disable comment is was removed
+     * @param failures - The unfiltered compiler failures
+     * @returns The filtered compiler failures
+     */
     function filterFailuresByChangedLines(failures: Map<string, CompilerFailure>) {
         // Filter failures to only include those on changed lines
         const filteredFailures = new Map<string, CompilerFailure>();
@@ -474,6 +498,12 @@ async function filterResultsByDiff(
     };
 }
 
+/**
+ * Enforces the new component guard by checking for manual memoization keywords in added files and attaching React compiler failures.
+ * @param failures - The compiler results to enforce the new component guard on
+ * @param diffResult - The diff result to check for added files
+ * @returns The enforced compiler results
+ */
 function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffResult) {
     const addedDiffFiles = new Set<string>();
     for (const file of diffResult.files) {
@@ -515,6 +545,8 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
         }
     }
 
+    // Check all added files for manual memoization keywords and attach React compiler failures.
+    // If no manual memoization keywords are found add the failures back to the regular failures.
     const addedComponentFailures: EnforcedAddedComponentFailureMap = new Map();
     for (const addedFilePath of addedDiffFiles) {
         const source = readSourceFile(addedFilePath);
@@ -543,6 +575,11 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
     };
 }
 
+/**
+ * Finds all manual memoization keywords matches in source file and returns their line and column numbers.
+ * @param source - The source code to search for manual memoization matches
+ * @returns An array of manual memoization matches
+ */
 function findManualMemoizationMatches(source: string): ManualMemoizationMatch[] {
     const matches: ManualMemoizationMatch[] = [];
 
@@ -579,6 +616,11 @@ function readSourceFile(filePath: string): string | null {
     }
 }
 
+/**
+ * Prints the results of the React Compiler compliance check.
+ * @param results - The compiler results to print
+ * @param options - The options for printing the results
+ */
 function printResults(
     {success, failures, suppressedFailures, enforcedAddedComponentFailures}: CompilerResults,
     {shouldPrintSuccesses, shouldPrintSuppressedErrors}: PrintResultsOptions,
@@ -679,6 +721,11 @@ function printFailures(failuresToPrint: FailureMap, level = 0) {
     }
 }
 
+/**
+ * Generates a report of the React Compiler compliance check.
+ * @param results - The compiler results to generate a report for
+ * @param outputFileName - The file name to save the report to
+ */
 function generateReport(results: CompilerResults, outputFileName = DEFAULT_REPORT_FILENAME): void {
     log('\n');
     logInfo('Creating React Compiler Compliance Check report:');

From 3f60d642686780c47a707b61f9d81a1be9e7d750 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Fri, 28 Nov 2025 18:30:37 +0100
Subject: [PATCH 26/45] fix: fail test if new files are not RC compatible

---
 scripts/react-compiler-compliance-check.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 1d9e7b60f8e6e..f3a1bfd985f67 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -144,7 +144,7 @@ async function check({
         generateReport(results, reportFileName);
     }
 
-    const isPassed = results.failures.size === 0;
+    const isPassed = results.failures.size === 0 && results.enforcedAddedComponentFailures?.size === 0;
     return isPassed;
 }
 

From 999b482e0dfedee899b41f0a5b60b00fe00347a8 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 08:51:19 +0100
Subject: [PATCH 27/45] fix: pass test if no enforced added components

---
 scripts/react-compiler-compliance-check.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index f3a1bfd985f67..37ee4c39fe3cb 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -144,7 +144,7 @@ async function check({
         generateReport(results, reportFileName);
     }
 
-    const isPassed = results.failures.size === 0 && results.enforcedAddedComponentFailures?.size === 0;
+    const isPassed = results.failures.size === 0 && (results.enforcedAddedComponentFailures?.size ?? 0) === 0;
     return isPassed;
 }
 

From 778bebe78e09ab3518b19e675894986c6fa117ce Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 08:51:27 +0100
Subject: [PATCH 28/45] fix: update final error message

---
 scripts/react-compiler-compliance-check.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 37ee4c39fe3cb..bf00fdb7348b9 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -710,7 +710,7 @@ function printResults(
     }
 
     log();
-    logError('The files above failed to compile with React Compiler, probably because of Rules of React violations. Please fix the issues and run the check again.');
+    logError('The files above failed the React Compiler compliance check. Please fix the issues and run the check again...');
 }
 
 function printFailures(failuresToPrint: FailureMap, level = 0) {

From 292eeef7325c6499a3b02590ccc1490487330abb Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:04:03 +0100
Subject: [PATCH 29/45] fix: missing continue

---
 scripts/react-compiler-compliance-check.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index bf00fdb7348b9..7748b854a0e52 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -523,10 +523,10 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
             continue;
         }
 
-        if (addedFileFailures.has(addedFilePath)) {
-            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-            const existingAddedFileFailuresMap = addedFileFailures.get(addedFilePath)!;
+        const existingAddedFileFailuresMap = addedFileFailures.get(addedFilePath);
+        if (existingAddedFileFailuresMap) {
             existingAddedFileFailuresMap.set(failureKey, failure);
+            continue;
         }
 
         addedFileFailures.set(addedFilePath, new Map<string, CompilerFailure>([[failureKey, failure]]));

From 40de5ffe30ef604dfb05fcb2540ca826da1c112a Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:05:14 +0100
Subject: [PATCH 30/45] fix: find multiple regex matches

---
 scripts/react-compiler-compliance-check.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 7748b854a0e52..ab1f92d1c2a0d 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -583,12 +583,12 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
 function findManualMemoizationMatches(source: string): ManualMemoizationMatch[] {
     const matches: ManualMemoizationMatch[] = [];
 
-    let regexMatch: RegExpExecArray | null;
     for (const keyword of Object.keys(MANUAL_MEMOIZATION_PATTERNS) as ManualMemoizationKeyword[]) {
         const regex = MANUAL_MEMOIZATION_PATTERNS[keyword];
         regex.lastIndex = 0;
-        regexMatch = regex.exec(source);
-        if (regexMatch) {
+
+        let regexMatch: RegExpExecArray | null;
+        while ((regexMatch = regex.exec(source)) !== null) {
             const matchIndex = regexMatch.index;
             const {line, column} = getLineAndColumnFromIndex(source, matchIndex);
             matches.push({keyword, line, column});

From b1f2952f469062b450bb318405df55619a112ddb Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:07:29 +0100
Subject: [PATCH 31/45] fix: logic error

---
 scripts/react-compiler-compliance-check.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index ab1f92d1c2a0d..3df68ded08f39 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -540,7 +540,7 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
             return;
         }
 
-        for (const [failureKey, failure] of failures) {
+        for (const [failureKey, failure] of addedFileFailuresMap) {
             nonAutoMemoEnforcedFailures.set(failureKey, failure);
         }
     }

From 3af2da6969a78a6688ef2be8129e28e1751934b5 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:11:34 +0100
Subject: [PATCH 32/45] fix: also check for Git diff hunk `oldCount`

---
 scripts/utils/Git.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/utils/Git.ts b/scripts/utils/Git.ts
index 8c7f15ee106d7..bdbe22918c464 100644
--- a/scripts/utils/Git.ts
+++ b/scripts/utils/Git.ts
@@ -293,7 +293,7 @@ class Git {
             return false;
         }
 
-        if (file.hunks.length === 1 && file.hunks.at(0)?.oldStart === 0) {
+        if (file.hunks.length === 1 && file.hunks.at(0)?.oldStart === 0 && file.hunks.at(0)?.oldCount === 0) {
             return true;
         }
 

From b7b11794ad61f3a38adfbc59804472b0dbe48cc0 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:17:44 +0100
Subject: [PATCH 33/45] test: add unit tests for `Git.isAddedFile`

---
 tests/unit/GitTest.ts | 264 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 264 insertions(+)

diff --git a/tests/unit/GitTest.ts b/tests/unit/GitTest.ts
index 88610a12d1350..14e198d103f6f 100644
--- a/tests/unit/GitTest.ts
+++ b/tests/unit/GitTest.ts
@@ -509,4 +509,268 @@ describe('Git', () => {
             expect(file.removedLines.size).toBe(0);
         });
     });
+
+    describe('isAddedDiffFile', () => {
+        it('returns true for newly added files with single hunk starting at line 0', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/new-file.ts b/new-file.ts
+                new file mode 100644
+                index 0000000..1234567
+                --- /dev/null
+                +++ b/new-file.ts
+                @@ -0,0 +1,3 @@
+                +const hello = 'world';
+                +const foo = 'bar';
+                +const baz = 'qux';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(true);
+        });
+
+        it('returns true for newly added files with single line', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/single-line.ts b/single-line.ts
+                new file mode 100644
+                index 0000000..1234567
+                --- /dev/null
+                +++ b/single-line.ts
+                @@ -0,0 +1,1 @@
+                +export const test = 'value';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(true);
+        });
+
+        it('returns false for files with modified lines', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/modified.ts b/modified.ts
+                index 1234567..abcdefg 100644
+                --- a/modified.ts
+                +++ b/modified.ts
+                @@ -1,1 +1,1 @@
+                -const old = 'value';
+                +const new = 'value';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+
+        it('returns false for files with removed lines', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/removed.ts b/removed.ts
+                index 1234567..abcdefg 100644
+                --- a/removed.ts
+                +++ b/removed.ts
+                @@ -2,2 +2,0 @@
+                -const removed1 = 'value1';
+                -const removed2 = 'value2';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+
+        it('returns false for files with both added and modified lines', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/mixed.ts b/mixed.ts
+                index 1234567..abcdefg 100644
+                --- a/mixed.ts
+                +++ b/mixed.ts
+                @@ -1,1 +1,2 @@
+                -const old = 'value';
+                +const new = 'value';
+                +const added = 'new';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+
+        it('returns false for files with both added and removed lines', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/mixed.ts b/mixed.ts
+                index 1234567..abcdefg 100644
+                --- a/mixed.ts
+                +++ b/mixed.ts
+                @@ -1,1 +1,1 @@
+                -const removed = 'value';
+                +const added = 'value';
+                @@ -3,0 +4,1 @@
+                +const newLine = 'new';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+
+        it('returns false for files with multiple hunks', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/multi-hunk.ts b/multi-hunk.ts
+                new file mode 100644
+                index 0000000..1234567
+                --- /dev/null
+                +++ b/multi-hunk.ts
+                @@ -0,0 +1,2 @@
+                +const first = 'value';
+                +const second = 'value';
+                @@ -0,0 +3,2 @@
+                +const third = 'value';
+                +const fourth = 'value';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+
+        it('returns false for files with added lines but oldStart !== 0', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/inserted.ts b/inserted.ts
+                index 1234567..abcdefg 100644
+                --- a/inserted.ts
+                +++ b/inserted.ts
+                @@ -5,0 +6,2 @@
+                +const inserted1 = 'value1';
+                +const inserted2 = 'value2';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+
+        it('returns false for files with added lines but oldCount !== 0', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/partial.ts b/partial.ts
+                index 1234567..abcdefg 100644
+                --- a/partial.ts
+                +++ b/partial.ts
+                @@ -1,1 +1,2 @@
+                 const existing = 'value';
+                +const added = 'new';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+
+        it('returns false for files with no added lines', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/no-additions.ts b/no-additions.ts
+                index 1234567..abcdefg 100644
+                --- a/no-additions.ts
+                +++ b/no-additions.ts
+                @@ -1,2 +1,0 @@
+                -const removed1 = 'value1';
+                -const removed2 = 'value2';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+
+        it('returns false for files with only modified lines and no additions', () => {
+            const mockDiffOutput = dedent(`
+                diff --git a/modified-only.ts b/modified-only.ts
+                index 1234567..abcdefg 100644
+                --- a/modified-only.ts
+                +++ b/modified-only.ts
+                @@ -1,1 +1,1 @@
+                -const old = 'old';
+                +const new = 'new';
+            `);
+
+            mockExecSync.mockReturnValue(mockDiffOutput);
+
+            const result = Git.diff('main');
+            const file = result.files.at(0);
+            expect(file).toBeDefined();
+            if (!file) {
+                return;
+            }
+
+            expect(Git.isAddedDiffFile(file)).toBe(false);
+        });
+    });
 });

From 3f16496060f37806a655d8f047cb353650b25108 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:18:56 +0100
Subject: [PATCH 34/45] Update RCAutoMemoComponent.tsx

---
 src/components/RCAutoMemoComponent.tsx | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/components/RCAutoMemoComponent.tsx b/src/components/RCAutoMemoComponent.tsx
index abaebfcca7e01..2a6c89eaf8cb9 100644
--- a/src/components/RCAutoMemoComponent.tsx
+++ b/src/components/RCAutoMemoComponent.tsx
@@ -1,17 +1,25 @@
-import {useCallback, useMemo} from 'react';
-import {Pressable} from 'react-native';
+import {memo, useCallback, useMemo} from 'react';
+import {View} from 'react-native';
 
 function RCAutoMemoComponent() {
     const someValue = useMemo(() => {
         return 'someValue';
     }, []);
 
+    const someOtherValue = useMemo(() => {
+        return 'someValue';
+    }, []);
+
     const someCallback = useCallback(() => {
         return 'someValue';
     }, []);
 
     // eslint-disable-next-line react-native-a11y/has-valid-accessibility-descriptors
-    return <Pressable onPress={someCallback}>{someValue}</Pressable>;
+    return (
+        <View onLayout={someCallback}>
+            {someValue} {someOtherValue}
+        </View>
+    );
 }
 
-export default RCAutoMemoComponent;
+export default memo(RCAutoMemoComponent);

From e7a97ef84aad003200e0ce03a17555374c75ac6f Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:21:33 +0100
Subject: [PATCH 35/45] chore: run `npm run gh-actions-build`

---
 .../getPullRequestIncrementalChanges/index.js  | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/.github/actions/javascript/getPullRequestIncrementalChanges/index.js b/.github/actions/javascript/getPullRequestIncrementalChanges/index.js
index 5cce6f0b14860..5ec39fec1476a 100644
--- a/.github/actions/javascript/getPullRequestIncrementalChanges/index.js
+++ b/.github/actions/javascript/getPullRequestIncrementalChanges/index.js
@@ -12746,6 +12746,24 @@ class Git {
             hasChanges: files.length > 0,
         };
     }
+    /**
+     * Check if a file from a Git diff is added.
+     *
+     * @param file - The file to check
+     * @returns true if the file is added, false otherwise
+     */
+    static isAddedDiffFile(file) {
+        const hasAddedLines = file.addedLines.size > 0;
+        const hasModifiedLines = file.modifiedLines.size > 0;
+        const hasRemovedLines = file.removedLines.size > 0;
+        if (!hasAddedLines || hasModifiedLines || hasRemovedLines) {
+            return false;
+        }
+        if (file.hunks.length === 1 && file.hunks.at(0)?.oldStart === 0 && file.hunks.at(0)?.oldCount === 0) {
+            return true;
+        }
+        return false;
+    }
     /**
      * Calculate the line number for a diff line based on the hunk and line type.
      */

From 95f4cddda6b62f97917f6daa9f45edeac2594b77 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:23:08 +0100
Subject: [PATCH 36/45] fix: sort manual memoization matches

---
 scripts/react-compiler-compliance-check.ts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 3df68ded08f39..5c8bd6bf33c25 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -595,6 +595,14 @@ function findManualMemoizationMatches(source: string): ManualMemoizationMatch[]
         }
     }
 
+    // Sort matches by line number first, then by column number
+    matches.sort((a, b) => {
+        if (a.line !== b.line) {
+            return a.line - b.line;
+        }
+        return a.column - b.column;
+    });
+
     return matches;
 }
 

From e734c163b131ecebafe9517458526004a6e6f5b7 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 2 Dec 2025 09:25:17 +0100
Subject: [PATCH 37/45] fix: update error message to include backquotes

---
 scripts/react-compiler-compliance-check.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 5c8bd6bf33c25..db4ab30213eb7 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -34,7 +34,7 @@ const MANUAL_MEMOIZATION_PATTERNS = {
 type ManualMemoizationKeyword = keyof typeof MANUAL_MEMOIZATION_PATTERNS;
 
 const MANUAL_MEMOIZATION_FAILURE_MESSAGE = (manualMemoizationKeyword: ManualMemoizationKeyword) =>
-    `Found a manual memoization usage of ${manualMemoizationKeyword}. Newly added React component files must not contain any manual memoization and instead be auto-memoized by React Compiler. Remove ${manualMemoizationKeyword} or disable automatic memoization by adding the \`"use no memo";\` directive at the beginning of the component and give a reason why automatic memoization is not applicable.`;
+    `Found a manual memoization usage of \`${manualMemoizationKeyword}\`. Newly added React component files must not contain any manual memoization and instead be auto-memoized by React Compiler. Remove \`${manualMemoizationKeyword}\` or disable automatic memoization by adding the \`"use no memo";\` directive at the beginning of the component and give a reason why automatic memoization is not applicable.`;
 
 const NO_MANUAL_MEMO_DIRECTIVE_PATTERN = /["']use no memo["']\s*;?/;
 

From 4ba3f14a8021ec4cba57ff29cabfaece5c2e3c43 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Wed, 3 Dec 2025 20:08:23 +0000
Subject: [PATCH 38/45] fix: optimize regex matching for manual memoization
 patterns

---
 scripts/react-compiler-compliance-check.ts | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index db4ab30213eb7..454e083b25eeb 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -585,11 +585,13 @@ function findManualMemoizationMatches(source: string): ManualMemoizationMatch[]
 
     for (const keyword of Object.keys(MANUAL_MEMOIZATION_PATTERNS) as ManualMemoizationKeyword[]) {
         const regex = MANUAL_MEMOIZATION_PATTERNS[keyword];
-        regex.lastIndex = 0;
+        const regexMatches = source.matchAll(regex);
 
-        let regexMatch: RegExpExecArray | null;
-        while ((regexMatch = regex.exec(source)) !== null) {
+        for (const regexMatch of regexMatches) {
             const matchIndex = regexMatch.index;
+            if (matchIndex === undefined) {
+                continue;
+            }
             const {line, column} = getLineAndColumnFromIndex(source, matchIndex);
             matches.push({keyword, line, column});
         }

From 1519deecf0192e5ed004e1484571468a093f727a Mon Sep 17 00:00:00 2001
From: Christoph Pader <christoph.pader@outlook.com>
Date: Tue, 9 Dec 2025 23:00:27 +0000
Subject: [PATCH 39/45] Update scripts/react-compiler-compliance-check.ts

Co-authored-by: Rory Abraham <47436092+roryabraham@users.noreply.github.com>
---
 scripts/react-compiler-compliance-check.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 691d0ffbe67e9..9aee95fd0aff4 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -696,7 +696,7 @@ function printResults(
 
     if (hasEnforcedAddedComponentFailures) {
         log();
-        logError(`These newly added component files were enforced to be automatically memoized with React Compiler:`);
+        logError(`The following newly added components should rely on React Compiler’s automatic memoization (manual memoization is not allowed):`);
         log();
 
         for (const [filePath, {manualMemoizationMatches, compilerFailures}] of enforcedAddedComponentFailures) {

From 25c720e6eff2f214ee277eeaf290d3cc6f2f5eae Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 9 Dec 2025 23:07:40 +0000
Subject: [PATCH 40/45] fix: extract `getLineAndColumnFromIndex` to FileUtils
 and refactor

---
 scripts/react-compiler-compliance-check.ts | 36 ++++++++--------------
 scripts/utils/FileUtils.ts                 | 16 ++++++++++
 2 files changed, 29 insertions(+), 23 deletions(-)
 create mode 100644 scripts/utils/FileUtils.ts

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 9aee95fd0aff4..0db33b071b7fc 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -7,10 +7,11 @@
  * It provides both CI and local development tools to enforce Rules of React compliance.
  */
 import {execSync} from 'child_process';
-import {readFileSync, writeFileSync} from 'fs';
-import {join} from 'path';
+import fs, {readFileSync} from 'fs';
+import path from 'path';
 import type {TupleToUnion} from 'type-fest';
 import CLI from './utils/CLI';
+import {getLineAndColumnFromIndex} from './utils/FileUtils';
 import Git from './utils/Git';
 import type {DiffResult} from './utils/Git';
 import {log, bold as logBold, error as logError, info as logInfo, note as logNote, success as logSuccess, warn as logWarn} from './utils/Logger';
@@ -547,7 +548,14 @@ function enforceNewComponentGuard({failures}: CompilerResults, diffResult: DiffR
     // If no manual memoization keywords are found add the failures back to the regular failures.
     const addedComponentFailures: EnforcedAddedComponentFailureMap = new Map();
     for (const addedFilePath of addedDiffFiles) {
-        const source = readSourceFile(addedFilePath);
+        let source: string | null = null;
+        try {
+            const absolutePath = path.join(process.cwd(), addedFilePath);
+            source = readFileSync(absolutePath, 'utf8');
+        } catch (error) {
+            logWarn(`Unable to read ${addedFilePath} while enforcing new component rules.`, error);
+        }
+
         if (!source || NO_MANUAL_MEMO_DIRECTIVE_PATTERN.test(source)) {
             addNonAutoMemoEnforcedFailures(addedFilePath);
             continue;
@@ -606,24 +614,6 @@ function findManualMemoizationMatches(source: string): ManualMemoizationMatch[]
     return matches;
 }
 
-function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
-    const substring = source.slice(0, index);
-    const line = substring.split('\n').length;
-    const lastLineBreakIndex = substring.lastIndexOf('\n');
-    const column = lastLineBreakIndex === -1 ? index + 1 : index - lastLineBreakIndex;
-    return {line, column};
-}
-
-function readSourceFile(filePath: string): string | null {
-    try {
-        const absolutePath = join(process.cwd(), filePath);
-        return readFileSync(absolutePath, 'utf8');
-    } catch (error) {
-        logWarn(`Unable to read ${filePath} while enforcing new component rules.`, error);
-        return null;
-    }
-}
-
 /**
  * Prints the results of the React Compiler compliance check.
  * @param results - The compiler results to print
@@ -736,8 +726,8 @@ function generateReport(results: CompilerResults, outputFileName = DEFAULT_REPOR
     logInfo('Creating React Compiler Compliance Check report:');
 
     // Save detailed report
-    const reportFile = join(process.cwd(), outputFileName);
-    writeFileSync(
+    const reportFile = path.join(process.cwd(), outputFileName);
+    fs.writeFileSync(
         reportFile,
         JSON.stringify(
             {
diff --git a/scripts/utils/FileUtils.ts b/scripts/utils/FileUtils.ts
new file mode 100644
index 0000000000000..6b3520037ed4a
--- /dev/null
+++ b/scripts/utils/FileUtils.ts
@@ -0,0 +1,16 @@
+/**
+ * Get the line and column from an index in a source string.
+ * @param source - The source string.
+ * @param index - The index in the source string.
+ * @returns The line and column.
+ */
+function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
+    const substring = source.slice(0, index);
+    const line = substring.split('\n').length;
+    const lastLineBreakIndex = substring.lastIndexOf('\n');
+    const column = lastLineBreakIndex === -1 ? index + 1 : index - lastLineBreakIndex;
+    return {line, column};
+}
+
+// eslint-disable-next-line import/prefer-default-export
+export {getLineAndColumnFromIndex};

From f60a205352860ae5b3e17a8999d7725672c29ab7 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 9 Dec 2025 23:31:33 +0000
Subject: [PATCH 41/45] feat: add error handling to `getLineAndColumnFromIndex`

---
 scripts/utils/FileUtils.ts | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/scripts/utils/FileUtils.ts b/scripts/utils/FileUtils.ts
index 6b3520037ed4a..a39f191e300b9 100644
--- a/scripts/utils/FileUtils.ts
+++ b/scripts/utils/FileUtils.ts
@@ -1,3 +1,10 @@
+const ERROR_MESSAGES = {
+    SOURCE_CANNOT_BE_EMPTY: 'Source cannot be empty',
+    INDEX_CANNOT_BE_NEGATIVE: 'Index cannot be negative',
+    // eslint-disable-next-line @typescript-eslint/naming-convention
+    INDEX_OUT_OF_BOUNDS: (sourceLength: number, index: number) => `Index ${index} is out of bounds for source length ${sourceLength}`,
+} as const;
+
 /**
  * Get the line and column from an index in a source string.
  * @param source - The source string.
@@ -5,6 +12,18 @@
  * @returns The line and column.
  */
 function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
+    if (source.length === 0) {
+        throw new Error(ERROR_MESSAGES.SOURCE_CANNOT_BE_EMPTY);
+    }
+
+    if (index < 0) {
+        throw new Error(ERROR_MESSAGES.INDEX_CANNOT_BE_NEGATIVE);
+    }
+
+    if (index > source.length) {
+        throw new Error(ERROR_MESSAGES.INDEX_OUT_OF_BOUNDS(source.length, index));
+    }
+
     const substring = source.slice(0, index);
     const line = substring.split('\n').length;
     const lastLineBreakIndex = substring.lastIndexOf('\n');
@@ -13,4 +32,4 @@ function getLineAndColumnFromIndex(source: string, index: number): {line: number
 }
 
 // eslint-disable-next-line import/prefer-default-export
-export {getLineAndColumnFromIndex};
+export {getLineAndColumnFromIndex, ERROR_MESSAGES};

From 16c5e0fa5e340545b947f7cf10f08ed3009eb8c6 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 9 Dec 2025 23:31:37 +0000
Subject: [PATCH 42/45] Create ScriptFileUtilsTest.ts

---
 tests/unit/ScriptFileUtilsTest.ts | 35 +++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 tests/unit/ScriptFileUtilsTest.ts

diff --git a/tests/unit/ScriptFileUtilsTest.ts b/tests/unit/ScriptFileUtilsTest.ts
new file mode 100644
index 0000000000000..b88af743faa31
--- /dev/null
+++ b/tests/unit/ScriptFileUtilsTest.ts
@@ -0,0 +1,35 @@
+import {ERROR_MESSAGES, getLineAndColumnFromIndex} from '../../scripts/utils/FileUtils';
+
+const multiLineSource = `abc
+hello
+world
+test
+multi
+line
+content`;
+
+describe('FileUtils (Scripts)', () => {
+    describe('getLineAndColumnFromIndex', () => {
+        it('should return correct line and column for multi-line source', () => {
+            expect(getLineAndColumnFromIndex(multiLineSource, 0)).toStrictEqual({line: 1, column: 1});
+            expect(getLineAndColumnFromIndex(multiLineSource, 3)).toStrictEqual({line: 1, column: 4});
+            expect(getLineAndColumnFromIndex(multiLineSource, 4)).toStrictEqual({line: 2, column: 1});
+            expect(getLineAndColumnFromIndex(multiLineSource, 10)).toStrictEqual({line: 3, column: 1});
+            expect(getLineAndColumnFromIndex(multiLineSource, multiLineSource.length)).toStrictEqual({line: 7, column: 8});
+        });
+
+        it('should throw an error if source is empty', () => {
+            expect(() => getLineAndColumnFromIndex('', 0)).toThrow(ERROR_MESSAGES.SOURCE_CANNOT_BE_EMPTY);
+        });
+
+        it('should throw an error if index is negative', () => {
+            expect(() => getLineAndColumnFromIndex(multiLineSource, -1)).toThrow(ERROR_MESSAGES.INDEX_CANNOT_BE_NEGATIVE);
+        });
+
+        it('should throw an error if index is out of bounds', () => {
+            expect(() => getLineAndColumnFromIndex(multiLineSource, multiLineSource.length + 10)).toThrow(
+                ERROR_MESSAGES.INDEX_OUT_OF_BOUNDS(multiLineSource.length, multiLineSource.length + 10),
+            );
+        });
+    });
+});

From 3170ca5825e59bcbc9e90b4d47d7f159433236e3 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 9 Dec 2025 23:33:48 +0000
Subject: [PATCH 43/45] refactor: FileUtils imports/exports

---
 scripts/react-compiler-compliance-check.ts |  4 ++--
 scripts/utils/FileUtils.ts                 |  6 ++++--
 tests/unit/ScriptFileUtilsTest.ts          | 18 +++++++++---------
 3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/scripts/react-compiler-compliance-check.ts b/scripts/react-compiler-compliance-check.ts
index 0db33b071b7fc..3e206c9190bfb 100644
--- a/scripts/react-compiler-compliance-check.ts
+++ b/scripts/react-compiler-compliance-check.ts
@@ -11,7 +11,7 @@ import fs, {readFileSync} from 'fs';
 import path from 'path';
 import type {TupleToUnion} from 'type-fest';
 import CLI from './utils/CLI';
-import {getLineAndColumnFromIndex} from './utils/FileUtils';
+import FileUtils from './utils/FileUtils';
 import Git from './utils/Git';
 import type {DiffResult} from './utils/Git';
 import {log, bold as logBold, error as logError, info as logInfo, note as logNote, success as logSuccess, warn as logWarn} from './utils/Logger';
@@ -598,7 +598,7 @@ function findManualMemoizationMatches(source: string): ManualMemoizationMatch[]
             if (matchIndex === undefined) {
                 continue;
             }
-            const {line, column} = getLineAndColumnFromIndex(source, matchIndex);
+            const {line, column} = FileUtils.getLineAndColumnFromIndex(source, matchIndex);
             matches.push({keyword, line, column});
         }
     }
diff --git a/scripts/utils/FileUtils.ts b/scripts/utils/FileUtils.ts
index a39f191e300b9..e73405859fb64 100644
--- a/scripts/utils/FileUtils.ts
+++ b/scripts/utils/FileUtils.ts
@@ -31,5 +31,7 @@ function getLineAndColumnFromIndex(source: string, index: number): {line: number
     return {line, column};
 }
 
-// eslint-disable-next-line import/prefer-default-export
-export {getLineAndColumnFromIndex, ERROR_MESSAGES};
+const FileUtils = {getLineAndColumnFromIndex};
+
+export default FileUtils;
+export {ERROR_MESSAGES};
diff --git a/tests/unit/ScriptFileUtilsTest.ts b/tests/unit/ScriptFileUtilsTest.ts
index b88af743faa31..847a3d65626ca 100644
--- a/tests/unit/ScriptFileUtilsTest.ts
+++ b/tests/unit/ScriptFileUtilsTest.ts
@@ -1,4 +1,4 @@
-import {ERROR_MESSAGES, getLineAndColumnFromIndex} from '../../scripts/utils/FileUtils';
+import FileUtils, {ERROR_MESSAGES} from '@scripts/utils/FileUtils';
 
 const multiLineSource = `abc
 hello
@@ -11,23 +11,23 @@ content`;
 describe('FileUtils (Scripts)', () => {
     describe('getLineAndColumnFromIndex', () => {
         it('should return correct line and column for multi-line source', () => {
-            expect(getLineAndColumnFromIndex(multiLineSource, 0)).toStrictEqual({line: 1, column: 1});
-            expect(getLineAndColumnFromIndex(multiLineSource, 3)).toStrictEqual({line: 1, column: 4});
-            expect(getLineAndColumnFromIndex(multiLineSource, 4)).toStrictEqual({line: 2, column: 1});
-            expect(getLineAndColumnFromIndex(multiLineSource, 10)).toStrictEqual({line: 3, column: 1});
-            expect(getLineAndColumnFromIndex(multiLineSource, multiLineSource.length)).toStrictEqual({line: 7, column: 8});
+            expect(FileUtils.getLineAndColumnFromIndex(multiLineSource, 0)).toStrictEqual({line: 1, column: 1});
+            expect(FileUtils.getLineAndColumnFromIndex(multiLineSource, 3)).toStrictEqual({line: 1, column: 4});
+            expect(FileUtils.getLineAndColumnFromIndex(multiLineSource, 4)).toStrictEqual({line: 2, column: 1});
+            expect(FileUtils.getLineAndColumnFromIndex(multiLineSource, 10)).toStrictEqual({line: 3, column: 1});
+            expect(FileUtils.getLineAndColumnFromIndex(multiLineSource, multiLineSource.length)).toStrictEqual({line: 7, column: 8});
         });
 
         it('should throw an error if source is empty', () => {
-            expect(() => getLineAndColumnFromIndex('', 0)).toThrow(ERROR_MESSAGES.SOURCE_CANNOT_BE_EMPTY);
+            expect(() => FileUtils.getLineAndColumnFromIndex('', 0)).toThrow(ERROR_MESSAGES.SOURCE_CANNOT_BE_EMPTY);
         });
 
         it('should throw an error if index is negative', () => {
-            expect(() => getLineAndColumnFromIndex(multiLineSource, -1)).toThrow(ERROR_MESSAGES.INDEX_CANNOT_BE_NEGATIVE);
+            expect(() => FileUtils.getLineAndColumnFromIndex(multiLineSource, -1)).toThrow(ERROR_MESSAGES.INDEX_CANNOT_BE_NEGATIVE);
         });
 
         it('should throw an error if index is out of bounds', () => {
-            expect(() => getLineAndColumnFromIndex(multiLineSource, multiLineSource.length + 10)).toThrow(
+            expect(() => FileUtils.getLineAndColumnFromIndex(multiLineSource, multiLineSource.length + 10)).toThrow(
                 ERROR_MESSAGES.INDEX_OUT_OF_BOUNDS(multiLineSource.length, multiLineSource.length + 10),
             );
         });

From 6b284c59b15ddcac2061bee4e9fd49bf6d96c701 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 9 Dec 2025 23:33:49 +0000
Subject: [PATCH 44/45] Delete RCAutoMemoComponent.tsx

---
 src/components/RCAutoMemoComponent.tsx | 25 -------------------------
 1 file changed, 25 deletions(-)
 delete mode 100644 src/components/RCAutoMemoComponent.tsx

diff --git a/src/components/RCAutoMemoComponent.tsx b/src/components/RCAutoMemoComponent.tsx
deleted file mode 100644
index 2a6c89eaf8cb9..0000000000000
--- a/src/components/RCAutoMemoComponent.tsx
+++ /dev/null
@@ -1,25 +0,0 @@
-import {memo, useCallback, useMemo} from 'react';
-import {View} from 'react-native';
-
-function RCAutoMemoComponent() {
-    const someValue = useMemo(() => {
-        return 'someValue';
-    }, []);
-
-    const someOtherValue = useMemo(() => {
-        return 'someValue';
-    }, []);
-
-    const someCallback = useCallback(() => {
-        return 'someValue';
-    }, []);
-
-    // eslint-disable-next-line react-native-a11y/has-valid-accessibility-descriptors
-    return (
-        <View onLayout={someCallback}>
-            {someValue} {someOtherValue}
-        </View>
-    );
-}
-
-export default memo(RCAutoMemoComponent);

From 4bd4f6420aab14e0b05b93a3ad6a365f96543ac3 Mon Sep 17 00:00:00 2001
From: Christoph Pader <chris@margelo.com>
Date: Tue, 9 Dec 2025 23:42:33 +0000
Subject: [PATCH 45/45] refactor: re-structure `FileUtils` as class-like export

---
 scripts/utils/FileUtils.ts | 48 +++++++++++++++++++-------------------
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/scripts/utils/FileUtils.ts b/scripts/utils/FileUtils.ts
index e73405859fb64..83e227c041da2 100644
--- a/scripts/utils/FileUtils.ts
+++ b/scripts/utils/FileUtils.ts
@@ -5,33 +5,33 @@ const ERROR_MESSAGES = {
     INDEX_OUT_OF_BOUNDS: (sourceLength: number, index: number) => `Index ${index} is out of bounds for source length ${sourceLength}`,
 } as const;
 
-/**
- * Get the line and column from an index in a source string.
- * @param source - The source string.
- * @param index - The index in the source string.
- * @returns The line and column.
- */
-function getLineAndColumnFromIndex(source: string, index: number): {line: number; column: number} {
-    if (source.length === 0) {
-        throw new Error(ERROR_MESSAGES.SOURCE_CANNOT_BE_EMPTY);
-    }
+const FileUtils = {
+    /**
+     * Get the line and column from an index in a source string.
+     * @param source - The source string.
+     * @param index - The index in the source string.
+     * @returns The line and column.
+     */
+    getLineAndColumnFromIndex: (source: string, index: number): {line: number; column: number} => {
+        if (source.length === 0) {
+            throw new Error(ERROR_MESSAGES.SOURCE_CANNOT_BE_EMPTY);
+        }
 
-    if (index < 0) {
-        throw new Error(ERROR_MESSAGES.INDEX_CANNOT_BE_NEGATIVE);
-    }
+        if (index < 0) {
+            throw new Error(ERROR_MESSAGES.INDEX_CANNOT_BE_NEGATIVE);
+        }
 
-    if (index > source.length) {
-        throw new Error(ERROR_MESSAGES.INDEX_OUT_OF_BOUNDS(source.length, index));
-    }
+        if (index > source.length) {
+            throw new Error(ERROR_MESSAGES.INDEX_OUT_OF_BOUNDS(source.length, index));
+        }
 
-    const substring = source.slice(0, index);
-    const line = substring.split('\n').length;
-    const lastLineBreakIndex = substring.lastIndexOf('\n');
-    const column = lastLineBreakIndex === -1 ? index + 1 : index - lastLineBreakIndex;
-    return {line, column};
-}
-
-const FileUtils = {getLineAndColumnFromIndex};
+        const substring = source.slice(0, index);
+        const line = substring.split('\n').length;
+        const lastLineBreakIndex = substring.lastIndexOf('\n');
+        const column = lastLineBreakIndex === -1 ? index + 1 : index - lastLineBreakIndex;
+        return {line, column};
+    },
+};
 
 export default FileUtils;
 export {ERROR_MESSAGES};