bazel-pre-pr

name	bazel-pre-pr
description	Runs pre-flight checks and deep code reviews on local commits of a feature branch before push or PR creation.

Bazel Pre-PR Pre-Flight Review (bazel-pre-pr)

This skill defines the pre-flight checks and local commit code review workflow to execute before a branch is pushed to remote or a pull request is created. It helps catch common Bazel migration bugs and style violations early.

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When to Use This Skill

• Run this skill before staging a commit for upload or pushing a new feature branch to GitHub.
• Trigger when the user requests "run pre-pr check", "review my local commits", or "verify my feature branch before PR".

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📋 Operational Workflow

Step 1: Feature Branch Validation (VCS Gate)

Before initiating any code analysis, you MUST verify that the local repository is in a valid state for code review:

1. Branch Check: Get the current git branch name (e.g., using git branch --show-current).
2. Gate Criterion: The current branch MUST NOT be main (or the default base branch). If it is main, stop immediately and print a hard-stop error: Error: Cannot run bazel-pre-pr on the 'main' branch. Please create a feature branch, commit your changes, and try again.
3. Commit Check: Ensure there is at least one local commit distinguishing the current branch from the base branch. Safely resolve the base branch (falling back to main if origin/main is not configured) and run the log:

   BASE_BRANCH=$(git rev-parse --verify origin/main >/dev/null 2>&1 && echo "origin/main" || echo "main")
   git log $BASE_BRANCH..HEAD --oneline
   

   If this returns empty, stop immediately and print: Error: No local commits found on this branch compared to the base branch.

Step 2: Spin Up Code Review Subagent

If the branch checks pass, spin up a subagent of type self (inheriting all tools and rules) to run the code review in the background:

• Role: Bazel Code Reviewer
• Initial Task:
  1. Retrieve the full diff of the local commits. Safely resolve the base branch (falling back to main if origin/main is not configured) and run the diff:

     BASE_BRANCH=$(git rev-parse --verify origin/main >/dev/null 2>&1 && echo "origin/main" || echo "main")
     git diff $BASE_BRANCH...HEAD
     

  2. Read the active migration guidelines from the repository root: docs/bazel-migration/GUIDELINES.md.
  3. Surgically audit all modifications in the diff against the guidelines listed in that file.
  4. Conduct a general, highly skeptical engineering review of the diff: check for logical robustness, verify assumptions, look for edge cases, resource cleanup misses, or race conditions, and identify opportunities to simplify the code.
  5. Write a triage report artifact named bazel_pre_pr_review.md to the repository root directory.
  6. The report MUST structure issues exactly like github-pr-triage:
     • Header: # Pre-PR Review: <branch_name>
     • Metadata: Commits analyzed, date, status.
     • Issues Grouped by Category:
       • For each issue:
         • Context: File path and line range.
         • Urgency: 🔥 Critical (causes compile/test failures or sandboxing violations), ⚠️ Warning (style/performance degradation), 💡 Suggestion.
         • The Flaw: Description of the guideline violated.
         • The Recommended Fix: Correct vs. Incorrect code block comparison.

Step 3: Present Triage Report to User

Once the subagent finishes and writes the bazel_pre_pr_review.md to the repository root:

1. Load the triage report from the repository root and present it to the user.
2. The report file MUST be created as a user-facing artifact with RequestFeedback: true in the metadata to render the Proceed button.
3. If no critical issues are found, notify the user that the branch is ready for push. If issues are found, prompt the user to approve the planned refactorings or fixes.