From becb32be3554abebfcf6b6283fbf393fd9768f03 Mon Sep 17 00:00:00 2001
From: Lucas Earl <earl.lucas@gmail.com>
Date: Mon, 21 Jul 2025 16:27:44 -0600
Subject: [PATCH 1/4] Add automated breaking changes detection for
 PRsImplements git-based analysis to detect API breaking changes in DataFusion
 PRs:- LogicalPlan enum modifications and variant removals  - DataFrame API
 public method changes- Generates detailed reports and integrates with GitHub
 ActionsAddresses #16532

---
 .github/workflows/dev.yml             |  50 ++++-
 ci/scripts/README.md                  |  49 +++++
 ci/scripts/breaking-changes-report.md |  33 ++++
 ci/scripts/detect-breaking-changes.sh | 251 ++++++++++++++++++++++++++
 4 files changed, 382 insertions(+), 1 deletion(-)
 create mode 100644 ci/scripts/README.md
 create mode 100644 ci/scripts/breaking-changes-report.md
 create mode 100755 ci/scripts/detect-breaking-changes.sh

diff --git a/.github/workflows/dev.yml b/.github/workflows/dev.yml
index aa4bd862e09e4..6465cce7a22d4 100644
--- a/.github/workflows/dev.yml
+++ b/.github/workflows/dev.yml
@@ -16,13 +16,58 @@
 # under the License.
 
 name: Dev
-on: [push, pull_request]
+on: [push, pull_request, workflow_dispatch]
 
 concurrency:
   group: ${{ github.repository }}-${{ github.head_ref || github.sha }}-${{ github.workflow }}
   cancel-in-progress: true
 
 jobs:
+  breaking-changes:
+    name: Breaking Changes Detection
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    permissions:
+      contents: read
+      pull-requests: write
+      issues: write
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Install GitHub CLI
+        run: |
+          if ! command -v gh &> /dev/null; then
+            curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | sudo dd of=/usr/share/keyrings/githubcli-archive-keyring.gpg
+            echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" | sudo tee /etc/apt/sources.list.d/github-cli.list > /dev/null
+            sudo apt update
+            sudo apt install gh
+          fi
+
+      - name: Run breaking changes detection
+        shell: bash
+        run: |
+          chmod +x ./ci/scripts/detect-breaking-changes.sh
+          ./ci/scripts/detect-breaking-changes.sh
+        timeout-minutes: 5
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Upload breaking changes report
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: breaking-changes-report
+          path: breaking-changes-report.md
+          retention-days: 30
+
   license-header-check:
     runs-on: ubuntu-latest
     name: Check License Header
@@ -35,6 +80,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # Fetch full history
+          token: ${{ secrets.GITHUB_TOKEN }}
       - uses: actions/setup-node@v4
         with:
           node-version: "20"
diff --git a/ci/scripts/README.md b/ci/scripts/README.md
new file mode 100644
index 0000000000000..147ed266072af
--- /dev/null
+++ b/ci/scripts/README.md
@@ -0,0 +1,49 @@
+# CI Scripts
+
+This directory contains scripts used in the DataFusion CI/CD pipeline.
+
+## Breaking Changes Detection
+
+### `detect-breaking-changes.sh`
+
+Automatically detects potential breaking changes in DataFusion pull requests using git-based analysis.
+
+**Features:**
+- Detects changes to LogicalPlan enums and variants
+- Monitors DataFrame API modifications
+- Checks SQL parser keyword changes
+- Generates detailed reports with diff snippets
+- Integrates with GitHub to post PR comments
+- Lightweight git-based analysis (no compilation required)
+
+**Usage:**
+```bash
+# Run from repository root
+./ci/scripts/detect-breaking-changes.sh
+
+# With custom base ref
+GITHUB_BASE_REF=v42.0.0 ./ci/scripts/detect-breaking-changes.sh
+```
+
+**Environment Variables:**
+- `GITHUB_BASE_REF`: Base branch/tag to compare against (default: `main`)
+- `GITHUB_HEAD_REF`: Head ref being tested (default: `HEAD`)
+- `GITHUB_TOKEN`: Required for posting PR comments
+- `GITHUB_ENV`: Set by GitHub Actions for CI integration
+
+**Output:**
+- Exit code 0: No breaking changes detected
+- Exit code 1: Breaking changes detected
+- Generates `breaking-changes-report.md` when issues found
+
+### `breaking-changes-report.md`
+
+Template/example of the report generated when breaking changes are detected. Contains:
+- Summary of detected changes
+- Links to DataFusion API stability guidelines
+- Required actions for PR authors
+- Approval requirements
+
+## Integration
+
+The breaking changes detection is integrated into the GitHub Actions workflow (`.github/workflows/dev.yml`) and runs automatically on all pull requests.
\ No newline at end of file
diff --git a/ci/scripts/breaking-changes-report.md b/ci/scripts/breaking-changes-report.md
new file mode 100644
index 0000000000000..86e1a3a322812
--- /dev/null
+++ b/ci/scripts/breaking-changes-report.md
@@ -0,0 +1,33 @@
+# 🚨 Breaking Changes Report
+
+## Summary
+Breaking changes detected in this PR that require the `api-change` label.
+
+## DataFusion API Stability Guidelines
+Per the [API Health Policy](https://datafusion.apache.org/contributor-guide/specification/api-health-policy.html):
+
+### Git-Based Analysis:
+- ⚠️  Breaking changes detected but specific patterns not identified
+- Review the modified files below for potential API changes
+
+### Source Files Modified:
+- datafusion/core/src/dataframe/mod.rs
+
+### All Files Modified:
+- .github/workflows/dev.yml
+- ci/scripts/detect-breaking-changes.sh
+- datafusion/core/src/dataframe/mod.rs
+
+## Required Actions:
+1. Add the `api-change` label to this PR
+2. Update CHANGELOG.md with breaking change details
+3. Consider adding deprecation warnings before removal
+4. Update migration guide if needed
+
+## Approval Requirements:
+- Breaking changes require approval from a DataFusion maintainer
+- Consider if this change is necessary or if a deprecation path exists
+
+## Note:
+This analysis uses git-based pattern detection to identify common breaking change patterns.
+Review the specific changes carefully to determine if they truly constitute breaking changes.
\ No newline at end of file
diff --git a/ci/scripts/detect-breaking-changes.sh b/ci/scripts/detect-breaking-changes.sh
new file mode 100755
index 0000000000000..5c37e1e4a9373
--- /dev/null
+++ b/ci/scripts/detect-breaking-changes.sh
@@ -0,0 +1,251 @@
+#!/bin/bash
+
+set -e
+
+# Ensure we're in the repository root
+if [ ! -f "Cargo.toml" ] || [ ! -d ".git" ]; then
+    echo "❌ Error: This script must be run from the repository root directory"
+    echo "Current directory: $(pwd)"
+    echo "Expected: A directory containing Cargo.toml and .git"
+    exit 1
+fi
+
+BASE_REF="${GITHUB_BASE_REF:-main}"
+HEAD_REF="${GITHUB_HEAD_REF:-HEAD}"
+
+echo "🔍 DataFusion Breaking Changes Detection"
+echo "Comparing against: $BASE_REF"
+echo "Current ref: $HEAD_REF"
+
+# Skip installation - we're only using git-based analysis
+echo "📋 Using git-based analysis for breaking change detection..."
+
+detect_datafusion_breaking_changes() {
+    local breaking_changes_found=1  # 1 = false in bash
+
+    echo "📋 Checking DataFusion-specific API rules..."
+
+    # Validate that we can access git and the base ref exists
+    if ! git rev-parse --verify "$BASE_REF" >/dev/null 2>&1; then
+        echo "⚠️  Warning: Base ref '$BASE_REF' not found, skipping git-based analysis"
+        return 1  # No breaking changes (can't detect them)
+    fi
+
+    # Only run git-based checks if we have a valid base ref
+    if [ -n "$BASE_REF" ]; then
+        echo "Checking for Rust source file changes..."
+        if git diff "$BASE_REF" --name-only 2>/dev/null | grep -qE "\.rs$"; then
+            echo "Rust files modified - running detailed checks..."
+
+            echo "Checking LogicalPlan stability..."
+            if check_logical_plan_changes; then
+                echo "❌ Breaking changes detected in LogicalPlan"
+                breaking_changes_found=0
+            else
+                echo "✅ No LogicalPlan breaking changes detected"
+            fi
+
+            echo "Checking DataFrame API..."
+            if check_dataframe_api_changes; then
+                echo "❌ Breaking changes detected in DataFrame API"
+                breaking_changes_found=0
+            else
+                echo "✅ No DataFrame API breaking changes detected"
+            fi
+
+            echo "Checking SQL parser compatibility..."
+            if check_sql_parser_changes; then
+                echo "❌ Breaking changes detected in SQL parser"
+                breaking_changes_found=0
+            else
+                echo "✅ No SQL parser breaking changes detected"
+            fi
+        else
+            echo "✅ No Rust source files modified - no breaking changes possible"
+        fi
+    else
+        echo "⚠️  Skipping git-based checks (no base ref available)"
+    fi
+
+    return $breaking_changes_found
+}
+
+check_logical_plan_changes() {
+    # Check for changes in LogicalPlan files using git diff
+    if git diff "$BASE_REF"..HEAD --name-only 2>/dev/null | grep -qE "(logical_plan|logical.*expr)"; then
+        echo "    LogicalPlan-related files modified"
+
+        # Check for enum variant removals (potential breaking change)
+        if git diff "$BASE_REF"..HEAD 2>/dev/null | grep -qE "^-.*enum.*LogicalPlan|^-.*pub.*enum"; then
+            echo "    Enum definitions modified"
+            return 0  # Breaking change detected
+        fi
+
+        # Check for removed enum variants
+        if git diff "$BASE_REF"..HEAD 2>/dev/null | grep -qE "^-\s*[A-Z][a-zA-Z]*\s*[\(\{,]"; then
+            echo "    Enum variants potentially removed"
+            return 0  # Breaking change detected
+        fi
+    fi
+
+    return 1  # No breaking changes
+}
+
+check_dataframe_api_changes() {
+    # Check if DataFrame public methods were changed
+    if git diff "$BASE_REF" --name-only 2>/dev/null | grep -qE "dataframe"; then
+        echo "    DataFrame files modified, checking for API changes..."
+
+        # Check for ANY changes to public methods (additions, removals, modifications)
+        if git diff "$BASE_REF" 2>/dev/null | grep -qE "^[-+].*pub fn"; then
+            echo "    Public DataFrame API methods modified"
+            return 0  # Breaking change detected
+        fi
+    fi
+
+    return 1  # No breaking changes
+}
+
+check_sql_parser_changes() {
+    # Check for SQL keyword removals
+    if git diff "$BASE_REF"..HEAD --name-only 2>/dev/null | grep -qE "keywords"; then
+        if git diff "$BASE_REF"..HEAD 2>/dev/null | grep -qE "^-.*,"; then
+            echo "    SQL keywords potentially removed"
+            return 0  # Breaking change detected
+        fi
+    fi
+
+    return 1  # No breaking changes
+}
+
+generate_breaking_changes_report() {
+    local output_file="breaking-changes-report.md"
+    local timestamp=$(date -u +"%Y-%m-%d %H:%M:%S UTC")
+
+    cat > "$output_file" << EOF
+# 🚨 Breaking Changes Report
+
+**Generated:** $timestamp
+**Base Ref:** $BASE_REF
+**Head Ref:** $HEAD_REF
+
+## Summary
+Breaking changes detected in this PR that require the \`api-change\` label.
+
+## DataFusion API Stability Guidelines
+Per the [API Health Policy](https://datafusion.apache.org/contributor-guide/specification/api-health-policy.html):
+
+EOF
+
+    echo "### Git-Based Analysis:" >> "$output_file"
+
+    # Only add git-based analysis if we have a base ref
+    if [ -n "$BASE_REF" ]; then
+        local changes_found=false
+
+        # Check for DataFrame API changes with details - EXCLUDE script files
+        if git diff "$BASE_REF" --name-only 2>/dev/null | grep -qE "dataframe.*\.rs$"; then
+            # Only look at .rs files, exclude ci/scripts
+            local dataframe_diff=$(git diff "$BASE_REF" 2>/dev/null -- "datafusion/*/src/**/*.rs" | grep -E "^[-+].*pub fn")
+            if [ -n "$dataframe_diff" ]; then
+                echo "- ⚠️  **DataFrame API changes detected:**" >> "$output_file"
+                echo "\`\`\`diff" >> "$output_file"
+                echo "$dataframe_diff" | head -10 >> "$output_file"
+                echo "\`\`\`" >> "$output_file"
+                echo "" >> "$output_file"
+                changes_found=true
+            fi
+        fi
+
+        # Check for LogicalPlan changes with details - EXCLUDE script files
+        local logical_plan_files=$(git diff "$BASE_REF" --name-only 2>/dev/null | grep -E "(logical_plan|logical.*expr).*\.rs$")
+        if [ -n "$logical_plan_files" ]; then
+            echo "- ⚠️  **LogicalPlan changes detected in:**" >> "$output_file"
+            echo "$logical_plan_files" | sed 's/^/  - /' >> "$output_file"
+            echo "" >> "$output_file"
+            changes_found=true
+        fi
+
+        # Show general public API changes - ONLY in .rs files, EXCLUDE ci/scripts
+        local api_changes=$(git diff "$BASE_REF" 2>/dev/null -- "datafusion/" "ballista/" | grep -E "^[-+].*pub (fn|struct|enum)")
+        if [ -n "$api_changes" ]; then
+            echo "- ⚠️  **Public API signature changes:**" >> "$output_file"
+            echo "\`\`\`diff" >> "$output_file"
+            echo "$api_changes" | head -10 >> "$output_file"
+            echo "\`\`\`" >> "$output_file"
+            echo "" >> "$output_file"
+            changes_found=true
+        fi
+
+        if [ "$changes_found" = false ]; then
+            echo "- ⚠️  Breaking changes detected but specific patterns not identified" >> "$output_file"
+            echo "- Review the modified files below for potential API changes" >> "$output_file"
+        fi
+
+        # Add list of changed SOURCE files only
+        echo "" >> "$output_file"
+        echo "### Source Files Modified:" >> "$output_file"
+        git diff "$BASE_REF" --name-only 2>/dev/null | grep -E "\.rs$" | head -20 | sed 's/^/- /' >> "$output_file" || {
+            echo "- No Rust source files modified" >> "$output_file"
+        }
+
+        echo "" >> "$output_file"
+        echo "### All Files Modified:" >> "$output_file"
+        git diff "$BASE_REF" --name-only 2>/dev/null | head -20 | sed 's/^/- /' >> "$output_file"
+    else
+        echo "- ⚠️  Git-based analysis skipped (no base ref available)" >> "$output_file"
+    fi
+
+    cat >> "$output_file" << EOF
+
+## Required Actions:
+1. Add the \`api-change\` label to this PR
+2. Update CHANGELOG.md with breaking change details
+3. Consider adding deprecation warnings before removal
+4. Update migration guide if needed
+
+## Approval Requirements:
+- Breaking changes require approval from a DataFusion maintainer
+- Consider if this change is necessary or if a deprecation path exists
+
+## Note:
+This analysis uses git-based pattern detection to identify common breaking change patterns.
+Review the specific changes carefully to determine if they truly constitute breaking changes.
+EOF
+
+    echo "📋 Report generated: $output_file"
+}
+
+main() {
+    if detect_datafusion_breaking_changes; then
+        echo ""
+        echo "🚨 FINAL RESULT: Breaking changes detected!"
+        # Only set GITHUB_ENV if it exists (in CI)
+        if [ -n "$GITHUB_ENV" ]; then
+            echo "BREAKING_CHANGES_DETECTED=true" >> "$GITHUB_ENV"
+        fi
+
+        generate_breaking_changes_report
+
+        # Only try to comment if we have GitHub CLI and are in a PR context
+        if command -v gh >/dev/null 2>&1 && [ -n "$GITHUB_TOKEN" ] && [ -n "$GITHUB_REPOSITORY" ] && [ "$GITHUB_EVENT_NAME" = "pull_request" ]; then
+            echo "💬 Adding PR comment..."
+            gh pr comment --body-file breaking-changes-report.md || {
+                echo "⚠️  Could not add PR comment, but report was generated"
+            }
+        else
+            echo "⚠️  Skipping PR comment (not in PR context or missing GitHub CLI)"
+        fi
+
+        exit 1
+    else
+        echo ""
+        echo "🎉 FINAL RESULT: No breaking changes detected"
+        # Only set GITHUB_ENV if it exists (in CI)
+        if [ -n "$GITHUB_ENV" ]; then
+            echo "BREAKING_CHANGES_DETECTED=false" >> "$GITHUB_ENV"
+        fi
+    fi
+}
+
+main "$@"
\ No newline at end of file

From 71b1621ca4f55f080bd4a6e8ad08e18906526093 Mon Sep 17 00:00:00 2001
From: Lucas Earl <earl.lucas@gmail.com>
Date: Mon, 21 Jul 2025 19:03:45 -0600
Subject: [PATCH 2/4] Delete ci/scripts/breaking-changes-report.md

---
 ci/scripts/breaking-changes-report.md | 33 ---------------------------
 1 file changed, 33 deletions(-)
 delete mode 100644 ci/scripts/breaking-changes-report.md

diff --git a/ci/scripts/breaking-changes-report.md b/ci/scripts/breaking-changes-report.md
deleted file mode 100644
index 86e1a3a322812..0000000000000
--- a/ci/scripts/breaking-changes-report.md
+++ /dev/null
@@ -1,33 +0,0 @@
-# 🚨 Breaking Changes Report
-
-## Summary
-Breaking changes detected in this PR that require the `api-change` label.
-
-## DataFusion API Stability Guidelines
-Per the [API Health Policy](https://datafusion.apache.org/contributor-guide/specification/api-health-policy.html):
-
-### Git-Based Analysis:
-- ⚠️  Breaking changes detected but specific patterns not identified
-- Review the modified files below for potential API changes
-
-### Source Files Modified:
-- datafusion/core/src/dataframe/mod.rs
-
-### All Files Modified:
-- .github/workflows/dev.yml
-- ci/scripts/detect-breaking-changes.sh
-- datafusion/core/src/dataframe/mod.rs
-
-## Required Actions:
-1. Add the `api-change` label to this PR
-2. Update CHANGELOG.md with breaking change details
-3. Consider adding deprecation warnings before removal
-4. Update migration guide if needed
-
-## Approval Requirements:
-- Breaking changes require approval from a DataFusion maintainer
-- Consider if this change is necessary or if a deprecation path exists
-
-## Note:
-This analysis uses git-based pattern detection to identify common breaking change patterns.
-Review the specific changes carefully to determine if they truly constitute breaking changes.
\ No newline at end of file

From 0136a3fa0164ab43f23efba76bf5352e136460e7 Mon Sep 17 00:00:00 2001
From: Lucas Earl <earl.lucas@gmail.com>
Date: Mon, 21 Jul 2025 22:54:29 -0600
Subject: [PATCH 3/4] Address reviewer feedback: Remove unnecessary
 dependencies- Remove Rust toolchain installation (not needed for git-based
 analysis)- Remove GitHub CLI installation (pre-installed on GitHub runners) 
 - Improve script robustness with consistent git diff range syntax- Make
 DataFrame API detection more specific to avoid false positivesAddresses
 reviewer comments on PR #16541

---
 .github/workflows/dev.yml             | 13 -------------
 ci/scripts/detect-breaking-changes.sh | 23 ++++++++++++-----------
 2 files changed, 12 insertions(+), 24 deletions(-)

diff --git a/.github/workflows/dev.yml b/.github/workflows/dev.yml
index 6465cce7a22d4..d1702440fd57c 100644
--- a/.github/workflows/dev.yml
+++ b/.github/workflows/dev.yml
@@ -38,18 +38,6 @@ jobs:
           fetch-depth: 0
           token: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
-
-      - name: Install GitHub CLI
-        run: |
-          if ! command -v gh &> /dev/null; then
-            curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | sudo dd of=/usr/share/keyrings/githubcli-archive-keyring.gpg
-            echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" | sudo tee /etc/apt/sources.list.d/github-cli.list > /dev/null
-            sudo apt update
-            sudo apt install gh
-          fi
-
       - name: Run breaking changes detection
         shell: bash
         run: |
@@ -58,7 +46,6 @@ jobs:
         timeout-minutes: 5
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Upload breaking changes report
         if: failure()
diff --git a/ci/scripts/detect-breaking-changes.sh b/ci/scripts/detect-breaking-changes.sh
index 5c37e1e4a9373..5f75cdce11e8e 100755
--- a/ci/scripts/detect-breaking-changes.sh
+++ b/ci/scripts/detect-breaking-changes.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-set -e
+set -euo pipefail  # Add -u for undefined variables and -o pipefail for pipe failures
 
 # Ensure we're in the repository root
 if [ ! -f "Cargo.toml" ] || [ ! -d ".git" ]; then
@@ -34,7 +34,7 @@ detect_datafusion_breaking_changes() {
     # Only run git-based checks if we have a valid base ref
     if [ -n "$BASE_REF" ]; then
         echo "Checking for Rust source file changes..."
-        if git diff "$BASE_REF" --name-only 2>/dev/null | grep -qE "\.rs$"; then
+        if git diff "$BASE_REF"..HEAD --name-only 2>/dev/null | grep -qE "\.rs$"; then
             echo "Rust files modified - running detailed checks..."
 
             echo "Checking LogicalPlan stability..."
@@ -93,11 +93,12 @@ check_logical_plan_changes() {
 
 check_dataframe_api_changes() {
     # Check if DataFrame public methods were changed
-    if git diff "$BASE_REF" --name-only 2>/dev/null | grep -qE "dataframe"; then
+    if git diff "$BASE_REF"..HEAD --name-only 2>/dev/null | grep -qE "dataframe.*\.rs$"; then
         echo "    DataFrame files modified, checking for API changes..."
 
         # Check for ANY changes to public methods (additions, removals, modifications)
-        if git diff "$BASE_REF" 2>/dev/null | grep -qE "^[-+].*pub fn"; then
+        # Only look at actual DataFrame source files, not test files
+        if git diff "$BASE_REF"..HEAD 2>/dev/null -- "datafusion/core/src/dataframe/" | grep -qE "^[-+].*pub fn"; then
             echo "    Public DataFrame API methods modified"
             return 0  # Breaking change detected
         fi
@@ -144,9 +145,9 @@ EOF
         local changes_found=false
 
         # Check for DataFrame API changes with details - EXCLUDE script files
-        if git diff "$BASE_REF" --name-only 2>/dev/null | grep -qE "dataframe.*\.rs$"; then
-            # Only look at .rs files, exclude ci/scripts
-            local dataframe_diff=$(git diff "$BASE_REF" 2>/dev/null -- "datafusion/*/src/**/*.rs" | grep -E "^[-+].*pub fn")
+        if git diff "$BASE_REF"..HEAD --name-only 2>/dev/null | grep -qE "dataframe.*\.rs$"; then
+            # Only look at .rs files in DataFrame source directories
+            local dataframe_diff=$(git diff "$BASE_REF"..HEAD 2>/dev/null -- "datafusion/core/src/dataframe/" | grep -E "^[-+].*pub fn")
             if [ -n "$dataframe_diff" ]; then
                 echo "- ⚠️  **DataFrame API changes detected:**" >> "$output_file"
                 echo "\`\`\`diff" >> "$output_file"
@@ -166,8 +167,8 @@ EOF
             changes_found=true
         fi
 
-        # Show general public API changes - ONLY in .rs files, EXCLUDE ci/scripts
-        local api_changes=$(git diff "$BASE_REF" 2>/dev/null -- "datafusion/" "ballista/" | grep -E "^[-+].*pub (fn|struct|enum)")
+        # Show general public API changes - ONLY in .rs files, EXCLUDE ci/scripts and tests
+        local api_changes=$(git diff "$BASE_REF"..HEAD 2>/dev/null -- "datafusion/" "ballista/" | grep -E "^[-+].*pub (fn|struct|enum)" | grep -v "/tests/")
         if [ -n "$api_changes" ]; then
             echo "- ⚠️  **Public API signature changes:**" >> "$output_file"
             echo "\`\`\`diff" >> "$output_file"
@@ -185,13 +186,13 @@ EOF
         # Add list of changed SOURCE files only
         echo "" >> "$output_file"
         echo "### Source Files Modified:" >> "$output_file"
-        git diff "$BASE_REF" --name-only 2>/dev/null | grep -E "\.rs$" | head -20 | sed 's/^/- /' >> "$output_file" || {
+        git diff "$BASE_REF"..HEAD --name-only 2>/dev/null | grep -E "\.rs$" | head -20 | sed 's/^/- /' >> "$output_file" || {
             echo "- No Rust source files modified" >> "$output_file"
         }
 
         echo "" >> "$output_file"
         echo "### All Files Modified:" >> "$output_file"
-        git diff "$BASE_REF" --name-only 2>/dev/null | head -20 | sed 's/^/- /' >> "$output_file"
+        git diff "$BASE_REF"..HEAD --name-only 2>/dev/null | head -20 | sed 's/^/- /' >> "$output_file"
     else
         echo "- ⚠️  Git-based analysis skipped (no base ref available)" >> "$output_file"
     fi

From 5f77dc5ea203ac86fcf9da893f39c7825115035a Mon Sep 17 00:00:00 2001
From: Lucas Earl <earl.lucas@gmail.com>
Date: Mon, 21 Jul 2025 22:57:44 -0600
Subject: [PATCH 4/4] Optimize checkout configuration and explain fetch-depth
 requirement- Remove unnecessary token parameter (not needed for public repo)-
 Add clear comments explaining why fetch-depth: 0 is required- Improve base
 ref handling for GitHub Actions PR context- Use origin/$GITHUB_BASE_REF for
 proper remote branch referenceAddresses reviewer question about checkout
 configuration necessity.

---
 .github/workflows/dev.yml             | 4 +++-
 ci/scripts/detect-breaking-changes.sh | 7 +++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/dev.yml b/.github/workflows/dev.yml
index d1702440fd57c..2c050fddc413f 100644
--- a/.github/workflows/dev.yml
+++ b/.github/workflows/dev.yml
@@ -35,8 +35,10 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
+          # Need full history to access base branch for git diff operations
+          # GitHub Actions only fetches single commit by default (fetch-depth: 1)
+          # Our script uses: git diff "$BASE_REF"..HEAD which requires base branch
           fetch-depth: 0
-          token: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Run breaking changes detection
         shell: bash
diff --git a/ci/scripts/detect-breaking-changes.sh b/ci/scripts/detect-breaking-changes.sh
index 5f75cdce11e8e..288a78b39ff60 100755
--- a/ci/scripts/detect-breaking-changes.sh
+++ b/ci/scripts/detect-breaking-changes.sh
@@ -13,6 +13,13 @@ fi
 BASE_REF="${GITHUB_BASE_REF:-main}"
 HEAD_REF="${GITHUB_HEAD_REF:-HEAD}"
 
+# In GitHub Actions PR context, use the proper base reference
+if [ -n "$GITHUB_BASE_REF" ]; then
+    # For PRs, GitHub provides GITHUB_BASE_REF (e.g., "main")
+    # We need to reference it as origin/$GITHUB_BASE_REF
+    BASE_REF="origin/$GITHUB_BASE_REF"
+fi
+
 echo "🔍 DataFusion Breaking Changes Detection"
 echo "Comparing against: $BASE_REF"
 echo "Current ref: $HEAD_REF"