fix-merge-conflict

name	fix-merge-conflict
description	Fix Acornlib pull request merge conflicts, especially conflicts only in generated `build/` files. Use when the user gives a PR id or URL, or asks to resolve merge conflicts in this repo: take conflicted build files from `master`, run `acorn verify` from the repo root to regenerate/update build artifacts, then commit and push the resolved PR branch when appropriate.

Fix Merge Conflict

Scope

Use this skill for merge conflicts in the Acornlib repository, especially PRs whose conflicts are only in generated build/ files. The build/ files are generated from .ac sources, but they should not be deleted wholesale or recreated from a clean state. The usual repair is to start from the version on master and let acorn verify update the generated files in place.

Rules

• Start with git status --short and identify unmerged paths before changing anything.
• Do not clean the build directory. Do not run git clean, delete build/, or remove generated files just to force regeneration.
• Do not overwrite unrelated user changes. If the worktree has unrelated local edits, leave them alone and keep the merge-conflict fix scoped to the PR branch.
• Default to origin/master as the source of truth for conflicted build/ files unless the PR explicitly targets another base branch.
• Do not push to master. When fixing a PR, commit and push only to the PR head branch if you have permission.
• Run acorn verify from the repository root after each resolution attempt and before reporting completion.

Workflow

1. If the user gave a PR number or URL, use the GitHub app or gh to find the PR head branch, head repository, and base branch. Fetch the base branch, then check out the PR head branch with push rights.

git fetch origin master
gh pr checkout <pr-number-or-url>

If the branch is already checked out and in a conflicted state, continue from that state.

2. If the PR branch has not yet been updated with master, merge the current base branch into it.

git merge origin/master

If the merge succeeds without conflicts, still run acorn verify; it may update generated files.

3. List conflicts.

git status --short
git diff --name-only --diff-filter=U

4. For each conflicted path under build/, take the file from master, then stage it as resolved.

git restore --source=origin/master --staged --worktree -- build/path/to/file
git add build/path/to/file

If a conflicted generated file does not exist on master, remove that path and stage the removal.

git rm -- build/path/to/file

5. Run the verifier from the repository root.

acorn verify

If verification succeeds, inspect the resulting generated-file changes. Stage the updated files produced by acorn verify.

6. If acorn verify fails, inspect the first real error and git status --short.

• If more build/ conflicts remain, resolve those from master and rerun acorn verify.
• If conflicts include .ac files or other source files, resolve them according to the source semantics, then rerun acorn verify.
• If the failure is not clearly related to the merge conflict, stop and report the command, error, and current git status instead of guessing.

7. Before committing, check that conflict markers are gone.

rg -n '^(<<<<<<<|=======|>>>>>>>)' .

8. Commit and push when the user asked you to fix a PR and the branch is ready.

git commit -m "Resolve merge conflicts"
git push

Completion Report

Report:

• the PR or branch fixed
• whether conflicts were only in build/ or also touched source files
• the final acorn verify result
• the commit SHA and push status, if committed
• any remaining blocker with the exact failing command and git status