fix: correct compiler plugin order, only handle createMiddleware in a …

[schiller-manuel]

…single plugin

fixes #5381

Summary by CodeRabbit

• Refactor

  • Reordered plugin execution sequence to improve server function compilation and optimization.

• Tests

  • Removed deprecated test suites and snapshots related to middleware transformation handling.
  • Updated test infrastructure to reflect changes in build-time behavior.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

This PR introduces support for calling server functions from within client-only functions by restructuring the build-time server function and middleware plugin pipeline. It adds a new test route demonstrating this pattern, guards against server-side execution of certain transformations, reorders plugin execution to perform server function transformations before dead-code elimination, and removes createMiddleware transformation logic from the start compiler plugin in favor of concentrating that responsibility in the create-server-fn plugin.

Changes

Cohort / File(s)	Summary
E2E test route additions e2e/react-start/server-functions/src/routeTree.gen.ts	Generated route tree update; adds ServerFnInClientOnlyFnRoute with id and path /server-fn-in-client-only-fn, updates FileRoutesByFullPath, FileRoutesByTo, FileRoutesById, and module declarations to include the new route.
E2E test route implementation e2e/react-start/server-functions/src/routes/server-fn-in-client-only-fn.tsx	New route file implementing the test case: defines a server function, wraps it in a createClientOnlyFn, renders a button to trigger it, and displays result/error state.
E2E test suite cleanup e2e/react-start/server-functions/tests/server-functions.spec.ts	Removes two tests related to server-only function behavior and associated error whitelist configuration.
Plugin guard and transformation simplification packages/start-plugin-core/src/create-server-fn-plugin/handleCreateMiddleware.ts	Adds early guard throwing error when env is 'server'; removes client-only conditional paths for inputValidator and server transformations, consolidating unconditional handling.
Plugin execution ordering packages/start-plugin-core/src/plugin.ts	Reorders plugin initialization: startCompilerPlugin now executes after createServerFnPlugin and TanStackServerFnPlugin, ensuring server function transformations and manifest registration occur before compilation-level dead-code elimination.
Compiler identifier wiring removal packages/start-plugin-core/src/start-compiler-plugin/compilers.ts	Removes the client-environment runtime wiring pathway for createMiddleware identifier registration and its handler.
Transform function constant update packages/start-plugin-core/src/start-compiler-plugin/constants.ts	Removes 'createMiddleware' from the transformFuncs constant array, reducing supported transform functions.
Compiler test refactor packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/createMiddleware.test.ts	Replaces parameterized test over environments with single client-only test; snapshot path changed to ./snapshots/client/${filename}.
Create-server-fn plugin test snapshots packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/*	Snapshot files updated: create-function-middleware.ts removes unused import; createMiddlewareDestructured.tsx, createMiddlewareDestructuredRename.tsx, createMiddlewareStarImport.tsx added as new client snapshots; createMiddlewareValidator.tsx removes unused zod import.
Create-server-fn plugin server snapshot removal packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/server/createStart.tsx	Removes entire server-start middleware setup exports (startInstance, serverFnMw, requestMw).
Start compiler plugin test removal packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/createMiddleware.test.ts	Entire test file removed; previously contained parameterized tests over client/server environments.
Start compiler plugin snapshots deletion packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/* packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/*	All snapshot files deleted across client and server directories, including createMiddlewareDestructured, createMiddlewareDestructuredRename, createMiddlewareStarImport, createMiddlewareValidator, factory.ts, and related server files.
Start compiler plugin test source removal packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/test-files/factory.ts	Removes exported createAuthMiddleware function and associated AuthMiddlewareOptions and AuthContext interfaces.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

• Plugin execution ordering (plugin.ts): requires understanding the rationale for reordering and impact on build-time manifest generation and dead-code elimination phases.
• Transform logic consolidation (handleCreateMiddleware.ts): the guard and removal of environment-specific conditionals need verification to ensure server-side safety and correct client-side behavior.
• Compiler wiring changes (compilers.ts, constants.ts): consolidation of createMiddleware handling away from start-compiler-plugin requires ensuring no orphaned references remain.
• Snapshot file migrations: numerous snapshot files added/removed/modified; verify the expected outputs match actual plugin transformation results, especially in the transition from dual-environment snapshots to client-only ones.

Possibly related PRs

• fix: generic env handling #5811 – Modifies the same plugin subsystems (create-server-fn-plugin and start-compiler-plugin), changing environment-aware plugin orchestration and transform plumbing.
• fix: only run middleware compiler in client env #5703 – Directly modifies packages/start-plugin-core/src/start-compiler-plugin/compilers.ts to adjust how createMiddleware identifiers are registered and handled.
• fix: compile createMiddleware using start-compiler-plugin #5245 – Modifies the same start-plugin-core compiler pipeline for createMiddleware (compilers.ts, constants.ts, and handleCreateMiddleware wiring).

Suggested reviewers

• schiller-manuel
• birkskyum

Poem

🐰 A function calls from client-only dreams,
To server lands via hidden streams,
The plugin reordered, guards now in place,
Middleware steps aside with grace.
Server transforms before DCE's sweep,
Client and server secrets now in sync so deep! 🌟

Pre-merge checks and finishing touches

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Out of Scope Changes check	⚠️ Warning	Most changes are scoped to fixing the plugin order and adjusting createMiddleware handling, but significant deletions of test snapshots and middleware tests appear to go beyond the stated issue fix.	Clarify why entire test suites for createMiddleware (createMiddleware-start-compiler-plugin) and snapshot files were removed if the fix only addresses plugin ordering for server functions in createClientOnlyFn.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	The PR addresses issue #5381 by adding a test case demonstrating server function usage in createClientOnlyFn and by reordering plugins to ensure proper transformation order.
Title check	✅ Passed	The title refers to correcting compiler plugin order and handling createMiddleware in a single plugin, which aligns with the actual changes made to plugin ordering and middleware transformation logic.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix-5381

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View your CI Pipeline Execution ↗ for commit 2de05a0

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---

☁️ Nx Cloud last updated this comment at 2025-12-20 22:49:40 UTC

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commit: 2de05a0

[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (2)

packages/start-plugin-core/src/create-server-fn-plugin/handleCreateMiddleware.ts (1)

5-13: Consider narrowing the type signature or documenting the constraint.

The function accepts env: 'client' | 'server' but immediately throws if env === 'server'. While this defensive guard is appropriate for catching misuse, consider either:

1. Narrowing the type to env: 'client' if this function should never receive a server env
2. Adding a JSDoc comment explaining why server is rejected

This would make the API contract clearer to callers.

🔎 Option 1: Narrow the type

 export function handleCreateMiddleware(
   path: babel.NodePath<t.CallExpression>,
   opts: {
-    env: 'client' | 'server'
+    env: 'client'
   },
 ) {
-  if (opts.env === 'server') {
-    throw new Error('handleCreateMiddleware should not be called on the server')
-  }

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/createMiddleware.test.ts (1)

10-14: Consider whether to preserve the dual-environment type signature.

The compile helper still accepts env: 'client' | 'server', but after this change, only 'client' is used in the tests. This isn't necessarily wrong—keeping the flexible signature allows for easier addition of server-side tests in the future if needed.

However, if middleware compilation is definitively client-only (per line 53's comment), you might consider either:

• Adding a clarifying comment explaining why the server option remains, or
• Narrowing the type to env: 'client' to match the actual usage

📜 Review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 8a20521 and 2de05a0.

📒 Files selected for processing (26)

• e2e/react-start/server-functions/src/routeTree.gen.ts (11 hunks)
• e2e/react-start/server-functions/src/routes/server-fn-in-client-only-fn.tsx (1 hunks)
• e2e/react-start/server-functions/tests/server-functions.spec.ts (0 hunks)
• packages/start-plugin-core/src/create-server-fn-plugin/handleCreateMiddleware.ts (2 hunks)
• packages/start-plugin-core/src/plugin.ts (2 hunks)
• packages/start-plugin-core/src/start-compiler-plugin/compilers.ts (0 hunks)
• packages/start-plugin-core/src/start-compiler-plugin/constants.ts (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/createMiddleware.test.ts (1 hunks)
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/create-function-middleware.ts (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructured.tsx (1 hunks)
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx (1 hunks)
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareStarImport.tsx (1 hunks)
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareValidator.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/server/createStart.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/createMiddleware.test.ts (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/createMiddlewareDestructured.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/createMiddlewareStarImport.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/factory.ts (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/create-function-middleware.ts (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/createMiddlewareDestructured.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/createMiddlewareDestructuredRename.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/createMiddlewareStarImport.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/createMiddlewareValidator.tsx (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/factory.ts (0 hunks)
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/test-files/factory.ts (0 hunks)

💤 Files with no reviewable changes (18)

• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareValidator.tsx
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/createMiddlewareValidator.tsx
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/create-function-middleware.ts
• packages/start-plugin-core/src/start-compiler-plugin/compilers.ts
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/server/createStart.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/create-function-middleware.ts
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/createMiddlewareStarImport.tsx
• e2e/react-start/server-functions/tests/server-functions.spec.ts
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/createMiddleware.test.ts
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/factory.ts
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/client/createMiddlewareDestructured.tsx
• packages/start-plugin-core/src/start-compiler-plugin/constants.ts
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/test-files/factory.ts
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/factory.ts
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/createMiddlewareStarImport.tsx
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/createMiddlewareDestructured.tsx
• packages/start-plugin-core/tests/createMiddleware-start-compiler-plugin/snapshots/server/createMiddlewareDestructuredRename.tsx

🧰 Additional context used

📓 Path-based instructions (2)

**/*.{ts,tsx}

📄 CodeRabbit inference engine (AGENTS.md)

Use TypeScript strict mode with extensive type safety for all code

Files:

• e2e/react-start/server-functions/src/routes/server-fn-in-client-only-fn.tsx
• packages/start-plugin-core/src/create-server-fn-plugin/handleCreateMiddleware.ts
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareStarImport.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/createMiddleware.test.ts
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructured.tsx
• packages/start-plugin-core/src/plugin.ts
• e2e/react-start/server-functions/src/routeTree.gen.ts

**/*.{js,ts,tsx}

📄 CodeRabbit inference engine (AGENTS.md)

Implement ESLint rules for router best practices using the ESLint plugin router

Files:

• e2e/react-start/server-functions/src/routes/server-fn-in-client-only-fn.tsx
• packages/start-plugin-core/src/create-server-fn-plugin/handleCreateMiddleware.ts
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareStarImport.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/createMiddleware.test.ts
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructured.tsx
• packages/start-plugin-core/src/plugin.ts
• e2e/react-start/server-functions/src/routeTree.gen.ts

🧠 Learnings (4)

📚 Learning: 2025-10-08T08:11:47.088Z

Learnt from: nlynzaad
Repo: TanStack/router PR: 5402
File: packages/router-generator/tests/generator/no-formatted-route-tree/routeTree.nonnested.snapshot.ts:19-21
Timestamp: 2025-10-08T08:11:47.088Z
Learning: Test snapshot files in the router-generator tests directory (e.g., files matching the pattern `packages/router-generator/tests/generator/**/routeTree*.snapshot.ts` or `routeTree*.snapshot.js`) should not be modified or have issues flagged, as they are fixtures used to verify the generator's output and are intentionally preserved as-is.

Applied to files:

• e2e/react-start/server-functions/src/routes/server-fn-in-client-only-fn.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareStarImport.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/createMiddleware.test.ts
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructured.tsx
• e2e/react-start/server-functions/src/routeTree.gen.ts

📚 Learning: 2025-11-02T16:16:24.898Z

Learnt from: nlynzaad
Repo: TanStack/router PR: 5732
File: packages/start-client-core/src/client/hydrateStart.ts:6-9
Timestamp: 2025-11-02T16:16:24.898Z
Learning: In packages/start-client-core/src/client/hydrateStart.ts, the `import/no-duplicates` ESLint disable is necessary for imports from `#tanstack-router-entry` and `#tanstack-start-entry` because both aliases resolve to the same placeholder file (`fake-start-entry.js`) in package.json during static analysis, even though they resolve to different files at runtime.

Applied to files:

• e2e/react-start/server-functions/src/routes/server-fn-in-client-only-fn.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareStarImport.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructured.tsx
• packages/start-plugin-core/src/plugin.ts

📚 Learning: 2025-12-16T02:59:11.506Z

Learnt from: schiller-manuel
Repo: TanStack/router PR: 6104
File: packages/start-plugin-core/tests/split-exports-plugin/snapshots/exports/functionExports.ts:1-1
Timestamp: 2025-12-16T02:59:11.506Z
Learning: In transformation test snapshots (e.g., split-exports plugin), comments at the top of snapshot files often describe the original input scenario being tested (e.g., "Multiple function exports") rather than the transformed output in the snapshot itself. This helps document what transformation is being validated.

Applied to files:

• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareStarImport.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx
• packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructured.tsx

📚 Learning: 2025-10-01T18:31:35.420Z

Learnt from: schiller-manuel
Repo: TanStack/router PR: 5330
File: e2e/react-start/custom-basepath/src/routeTree.gen.ts:58-61
Timestamp: 2025-10-01T18:31:35.420Z
Learning: Do not review files named `routeTree.gen.ts` in TanStack Router repositories, as these are autogenerated files that should not be manually modified.

Applied to files:

• e2e/react-start/server-functions/src/routeTree.gen.ts

🧬 Code graph analysis (4)

e2e/react-start/server-functions/src/routes/server-fn-in-client-only-fn.tsx (2)

packages/start-client-core/src/index.tsx (1)

• createClientOnlyFn (12-12)

packages/router-core/src/ssr/tsrScript.ts (1)

• p (16-18)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/createMiddleware.test.ts (1)

packages/start-plugin-core/src/create-server-fn-plugin/compiler.ts (1)

• compile (204-282)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructured.tsx (6)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx (4)

• withUseServer (2-4)
• withoutUseServer (5-7)
• withVariable (8-10)
• withZodValidator (11-13)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareStarImport.tsx (4)

• withUseServer (2-4)
• withoutUseServer (5-7)
• withVariable (8-10)
• withZodValidator (11-13)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareValidator.tsx (1)

• withUseServer (2-4)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/test-files/createMiddlewareDestructuredRename.tsx (4)

• withUseServer (4-12)
• withoutUseServer (14-22)
• withVariable (24-26)
• withZodValidator (45-51)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/test-files/createMiddlewareDestructured.tsx (4)

• withUseServer (4-12)
• withoutUseServer (14-22)
• withVariable (24-26)
• withZodValidator (45-51)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/test-files/createMiddlewareStarImport.tsx (4)

• withUseServer (4-13)
• withoutUseServer (15-23)
• withVariable (25-27)
• withZodValidator (46-52)

packages/start-plugin-core/src/plugin.ts (1)

packages/start-plugin-core/src/start-compiler-plugin/plugin.ts (1)

• startCompilerPlugin (69-111)

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• GitHub Check: Preview
• GitHub Check: Test

🔇 Additional comments (13)

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructuredRename.tsx (1)

1-13: LGTM! Test snapshot correctly demonstrates renamed import transformation.

This snapshot file properly validates that the plugin handles createMiddleware when imported with a rename (as middlewareFn). The identical configurations across all four exports are intentional for testing that the transformation uniformly processes different middleware instances under the renamed import pattern.

packages/start-plugin-core/src/create-server-fn-plugin/handleCreateMiddleware.ts (2)

51-56: LGTM!

The simplified logic correctly removes the validator call expression by replacing it with the callee's object. The isMemberExpression check provides appropriate type safety.

---

63-70: LGTM!

The conditional properly checks for the existence of both callExpressionPaths.server and serverFnPath.node before performing the transformation. The simplification is valid since the early guard ensures this only executes in client context.

packages/start-plugin-core/src/plugin.ts (1)

388-434: Excellent fix with clear documentation!

The plugin reordering correctly addresses issue #5381. The comment clearly explains the critical ordering requirement:

1. createServerFnPlugin injects 'use server' directive
2. TanStackServerFnPlugin extracts and registers functions in manifest
3. startCompilerPlugin runs DCE last

This ensures server functions referenced inside createClientOnlyFn callbacks are registered in the manifest before DCE can remove them. The detailed comment will help future maintainers understand why this order matters.

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareDestructured.tsx (1)

1-13: LGTM! Client-side transformation snapshot is correct.

This test snapshot correctly demonstrates the expected client-side output after the plugin processes createMiddleware calls. Comparing to the test input file, the .server() method chains and their implementations have been properly stripped, leaving only the base createMiddleware({ id: 'test' }) calls—which is the expected behavior for client bundles.

The snapshot aligns with the PR objective of consolidating createMiddleware handling in a single plugin and validates that the plugin ordering fix maintains correct transformation behavior.

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/snapshots/client/createMiddlewareStarImport.tsx (1)

1-13: LGTM! Valid test snapshot documenting star import transformation.

This snapshot correctly represents the expected client-side output after the plugin transforms createMiddleware calls using a star import pattern. The identical configurations across all four exports (id: 'test') are intentional, as this tests the transformation behavior rather than runtime logic. The filename clearly describes the test scenario being validated.

Based on learnings, transformation test snapshots document what transformation is being validated and serve as fixtures for verifying plugin output.

e2e/react-start/server-functions/src/routes/server-fn-in-client-only-fn.tsx (5)

1-3: LGTM: Imports are appropriate for the test case.

The imports correctly include the necessary TanStack Start primitives (createServerFn, createClientOnlyFn) and Router utilities to demonstrate the fix for issue #5381.

---

5-8: LGTM: Server function definition is correct.

The server function uses the standard createServerFn().handler() pattern and returns a simple string, which is appropriate for this test scenario.

---

10-18: LGTM: Core test case correctly demonstrates the fix.

The client-only function properly calls the server function and transforms its result. The inline comment (lines 11-14) provides valuable context about the compilation order issue that this PR addresses, making this an excellent regression test.

---

20-22: LGTM: Route definition follows standard patterns.

The file route is correctly configured with an appropriate path name that describes the test scenario.

---

24-63: LGTM: Test component is well-structured.

The component implementation includes:

• Proper error handling with try/catch
• Clear test-ids for e2e test assertions
• Expected result display that correctly matches the composed output from both functions
• Conditional rendering of result and error states

This provides a robust test case for the compilation order fix.

e2e/react-start/server-functions/src/routeTree.gen.ts (1)

1-705: Autogenerated file - changes are expected.

This routeTree.gen.ts file is autogenerated by TanStack Router and correctly includes the new /server-fn-in-client-only-fn route across all type declarations, route mappings, and the route tree structure. No manual modifications are needed.

Based on learnings, autogenerated route tree files should not be manually modified or have issues flagged.

packages/start-plugin-core/tests/createMiddleware-create-server-fn-plugin/createMiddleware.test.ts (1)

53-60: The comment "Middleware compilation only happens on the client" is verified and correct.

The handleCreateMiddleware function explicitly throws an error if called with env: 'server', confirming that middleware processing is intentionally client-only. Server-side test removal is appropriate since server environment processing is unsupported by design.

However, consider whether the compiler should guard against passing server env at the call site (compiler.ts line 270-271) to provide clearer error messaging, rather than relying on the handler rejection. This would shift the error earlier in the compilation pipeline.