[release/v7.6] Fix merge conflict checker for empty file lists and filter *.cs files (#26556)

2026-06-08 12:12:50 +00:00 · 2025-12-02 15:56:04 -08:00
parent 0b313f7111
commit c63af4e2c9
4 changed files with 592 additions and 1 deletions
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+# Merge Conflict Checker
+
+This composite GitHub Action checks for Git merge conflict markers in files changed in pull requests.
+
+## Purpose
+
+Automatically detects leftover merge conflict markers (`<<<<<<<`, `=======`, `>>>>>>>`) in pull request files to prevent them from being merged into the codebase.
+
+## Usage
+
+### In a Workflow
+
+```yaml
+- name: Check for merge conflict markers
+  uses: "./.github/actions/infrastructure/merge-conflict-checker"
+```
+
+### Complete Example
+
+```yaml
+jobs:
+  merge_conflict_check:
+    name: Check for Merge Conflict Markers
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    permissions:
+      pull-requests: read
+      contents: read
+    steps:
+      - name: checkout
+        uses: actions/checkout@v5
+
+      - name: Check for merge conflict markers
+        uses: "./.github/actions/infrastructure/merge-conflict-checker"
+```
+
+## How It Works
+
+1. **File Detection**: Uses GitHub's API to get the list of files changed in the pull request
+2. **Marker Scanning**: Reads each changed file and searches for the following markers:
+   - `<<<<<<<` (conflict start marker)
+   - `=======` (conflict separator)
+   - `>>>>>>>` (conflict end marker)
+3. **Result Reporting**: 
+   - If markers are found, the action fails and lists all affected files
+   - If no markers are found, the action succeeds
+
+## Outputs
+
+- `files-checked`: Number of files that were checked
+- `conflicts-found`: Number of files containing merge conflict markers
+
+## Behavior
+
+- **Event Support**: Only works with `pull_request` events
+- **File Handling**:
+  - Checks only files that were added, modified, or renamed
+  - Skips deleted files
+  - **Filters out `*.cs` files** (C# files are excluded from merge conflict checking)
+  - Skips binary/unreadable files
+  - Skips directories
+- **Empty File List**: Gracefully handles cases where no files need checking (e.g., PRs that only delete files)
+
+## Example Output
+
+When conflict markers are detected:
+
+```
+❌ Merge conflict markers detected in the following files:
+  - src/example.cs
+    Markers found: <<<<<<<, =======, >>>>>>>
+  - README.md
+    Markers found: <<<<<<<, =======, >>>>>>>
+
+Please resolve these conflicts before merging.
+```
+
+When no markers are found:
+
+```
+✅ No merge conflict markers found
+```
+
+## Integration
+
+This action is integrated into the `linux-ci.yml` workflow and runs automatically on all pull requests to ensure code quality before merging.
@@ -0,0 +1,37 @@
+name: 'Check for Merge Conflict Markers'
+description: 'Checks for Git merge conflict markers in changed files for pull requests'
+author: 'PowerShell Team'
+
+outputs:
+  files-checked:
+    description: 'Number of files checked for merge conflict markers'
+    value: ${{ steps.check.outputs.files-checked }}
+  conflicts-found:
+    description: 'Number of files with merge conflict markers'
+    value: ${{ steps.check.outputs.conflicts-found }}
+
+runs:
+  using: 'composite'
+  steps:
+    - name: Get changed files
+      id: changed-files
+      uses: "./.github/actions/infrastructure/get-changed-files"
+
+    - name: Check for merge conflict markers
+      id: check
+      shell: pwsh
+      env:
+        CHANGED_FILES_JSON: ${{ steps.changed-files.outputs.files }}
+      run: |
+        # Get changed files from environment variable (secure against injection)
+        $changedFilesJson = $env:CHANGED_FILES_JSON
+        # Ensure we always have an array (ConvertFrom-Json returns null for empty JSON arrays)
+        $changedFiles = @($changedFilesJson | ConvertFrom-Json)
+
+        # Import ci.psm1 and run the check
+        Import-Module "$env:GITHUB_WORKSPACE/tools/ci.psm1" -Force
+        Test-MergeConflictMarker -File $changedFiles -WorkspacePath $env:GITHUB_WORKSPACE
+
+branding:
+  icon: 'alert-triangle'
+  color: 'red'