Fix linter in git worktrees

[gijswijs]

Summary

• Fix make lint failing to filter existing issues when run from a
  git worktree
• Mount the main git directory in Docker when running from a
  worktree

Problem

When running make lint in a git worktree, the linter reports thousands of false positives. This happens because:

1. The .golangci.yml config uses new-from-rev: 03eab4db... to only show newly introduced issues
2. This relies on revgrep accessing git history to compute the diff
3. In a worktree, .git is a file (not a directory) containing a pointer like gitdir: /path/to/main/.git/worktrees/branch-name
4. The Docker container only mounts the worktree directory (-v $(pwd):/build), not the main .git directory
5. revgrep can't find the git repository and the diff filter fails silently, causing all ~32k existing issues to be reported

The linter logs show: level=warning msg="[runner] Can't process result by diff processor: can't prepare diff by revgrep: no version control repository found"

Solution

Detect if we're in a git worktree. Use git rev-parse --git-common-dir to get the path to the main git directory . If this is not .git we know we are in a worktree. We set the common directory path and mount it into the Docker container. This allows revgrep to access git history and correctly filter issues.

The fix is backwards compatible—in a normal (non-worktree) repo, no additional volume is mounted.

Test plan

• Run make lint in a git worktree - should pass with 0 issues, or exactly the same amount of issues compared to when not working in a git worktree
• Run make lint in the main repo - should still work as before
• Verify the docker command includes -v /path/to/.git:/path/to/.git when in a worktree

[gemini-code-assist]

Summary of Changes

Hello @gijswijs, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves a critical issue preventing the make lint command from functioning correctly within git worktrees. The problem stemmed from the linter's inability to access the full git history when operating inside a Docker container that only mounted the worktree's directory. The implemented solution intelligently detects worktree environments and ensures the main git repository is also mounted, thereby restoring the linter's intended behavior of filtering issues based on recent changes.

Highlights

• Linter Fix for Git Worktrees: Addresses an issue where make lint would fail to correctly filter existing issues when run from a git worktree, reporting thousands of false positives.
• Docker Volume Mounting: Implements a solution to detect git worktrees and conditionally mount the main git directory into the Docker container, allowing the linter's diff processor to access git history.

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Changelog

• Makefile
  • Added logic to detect if the current execution environment is a git worktree by checking if .git is a file.
  • If a worktree is detected, the path to the main git directory is extracted.
  • A new Docker volume mount (-v $(GIT_WORKTREE_PARENT):$(GIT_WORKTREE_PARENT)) is conditionally added to the DOCKER_TOOLS command to ensure the main git repository is accessible within the container.

Activity

• No human activity (comments, reviews) has been recorded on this pull request yet.

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[starius]

LGTM! 🏆
One note on narrowing the scope of the change to make lint only, not to all dockerized targets.