Refactor patch generation from workflow step to MCP server

[Copilot]

Moves git patch generation from a dedicated workflow step to the safe-outputs MCP server, where it executes when create_pull_request or push_to_pull_request_branch tools are called. This provides immediate error feedback when no changes exist, rather than discovering it later in processing jobs.

Implementation

• MCP Server (safe_outputs_mcp_server.cjs)

  • Added generateGitPatch() with two strategies: named branch and HEAD commits
  • Handlers throw errors immediately if patch is empty or generation fails
  • Returns patch metadata (path, size, lines) on success

• Workflow Compilation (git_patch.go, compiler_yaml.go)

  • Removed patch generation step from main job
  • Retained upload artifact step for processing job compatibility
  • Updated generateGitPatchStep() → generateGitPatchUploadStep()

• Tests

  • Added safe_outputs_mcp_server_patch.test.cjs with 217 lines of coverage
  • Updated existing tests to expect no generation step in main job

Error Flow

Before:

AI execution → (always) generate patch → upload artifact → processing job discovers empty patch

After:

AI execution → tool call → generate patch (fails fast if empty) → upload artifact → processing job

Error messages throw at tool invocation:

• "No changes to commit - patch is empty"
• "Failed to generate patch: [details]"

Backward Compatibility

Processing jobs continue downloading aw.patch artifact as before. Upload step runs if: always() regardless of patch existence.

Warning

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• https://api.github.com/user
  • Triggering command: /usr/bin/gh gh api user --jq .login (http block)

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Original prompt

Refactor the aw.patch patch generation to JavaScript in the safe output MCP server. Generate the patch when the tool is called. Report error when the patch is empty.

Remove dedicated step to generate patch.

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[Copilot]

Pull request overview

This PR refactors git patch generation from a dedicated workflow step to the safe-outputs MCP server, where it executes when create_pull_request or push_to_pull_request_branch tools are called. This architectural change enables immediate error feedback when no changes exist, rather than discovering it later in processing jobs.

Key changes:

• Adds generateGitPatch() function to the MCP server with two strategies (named branch and HEAD commits)
• Handlers throw errors immediately if patch is empty or generation fails
• Removes the "Generate git patch" workflow step from main job
• Retains upload artifact step for backward compatibility with processing jobs

Reviewed changes

Copilot reviewed 85 out of 85 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pkg/workflow/js/safe_outputs_mcp_server.cjs	Added generateGitPatch() function with two fallback strategies and integration into create/push handlers
pkg/workflow/js/safe_outputs_mcp_server_patch.test.cjs	New test file with 217 lines covering patch generation logic, error handling, and git command patterns
pkg/workflow/git_patch.go	Renamed function from generateGitPatchStep() to generateGitPatchUploadStep() and removed patch generation logic
pkg/workflow/compiler_yaml.go	Updated function call and added explanatory comments about the architectural change
pkg/workflow/git_patch_test.go	Updated test expectations to verify patch generation step is NOT in main job
pkg/workflow/patch_generation_test.go	Updated test expectations and comments to reflect MCP server architecture
.github/workflows/*.lock.yml	Multiple compiled workflows now include the generateGitPatch() function and no longer have the "Generate git patch" step
.changeset/patch-refactor-patch-generation-to-mcp-server.md	Changeset documenting the refactoring

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