ums: post-merge worktree-tidy pitfalls

[d-morrison]

Summary

• Extends post-merge step 2 with two worktree-specific pitfalls hit during PR #141's post-merge:
  • git worktree remove <path> fails when called from inside the worktree being removed — documents the git -C "$REPO" worktree remove "$(pwd)" fix using git rev-parse --git-common-dir
  • git pull --ff-only fails when the main checkout has diverged from a concurrent session's local commits — documents skipping the pull rather than force-merging another session's work
• Adds an anti-pattern: don't force-pull or reset a diverged main checkout

Test plan

• Read step 2 of the updated skill and confirm both worktree cases are clear
• Verify the anti-pattern list covers the diverged-main scenario

🤖 Generated with Claude Code

[d-morrison]

Working on this — paws off until I'm done.

[claude]

Gap: after a diverged git pull --ff-only fails, GitHub typically auto-deletes the remote PR branch on merge. The failed pull still ran git fetch, so origin/<pr-branch> may now be gone. With no upstream ref to check, git branch -d <merged-branch> falls back to checking reachability from HEAD (the diverged local main), which doesn't contain the merge commit yet — so it refuses with "not fully merged."

Step 1 already confirms via gh pr view that the PR is merged, so we know it's safe. Suggest noting that if git branch -d refuses here, the verification from step 1 makes it safe to use git branch -D:

Suggested change

	The branch deletion is what matters; another session will pull main when it's
	has local commits from a concurrent session that hasn't been pushed. Don't
	force-merge or reset their work — skip the pull and delete the branch only.
	The branch deletion is what matters; another session will pull main when it's
	ready. If `git branch -d` refuses because local `main` doesn't yet include
	the merge (diverged HEAD, remote branch already deleted), use `git branch -D` —
	step 1 already confirmed the PR is merged, so the force-delete is safe here.

[claude]

Minor grammar: "a concurrent session that haven't" should be "hasn't" (the session hasn't pushed, or: "local commits … that haven't been pushed").

Suggested change

	has local commits from a concurrent session that haven't been pushed. Don't
	has local commits from a concurrent session that hasn't been pushed. Don't

[d-morrison]

ARD Summary — round 1

#	Finding	Disposition	Notes
1	Grammar: "haven't" → "hasn't" (line 79)	✅ Addressed	Fixed
2	git branch -d may refuse when remote branch is already deleted (diverged HEAD)	✅ Addressed	Added git branch -D escape hatch with note that step 1's gh pr view confirmation makes it safe

[claude]

$(pwd) gives the shell's current directory, which may be a subdirectory of the worktree (e.g. worktree/src/). git worktree remove expects the registered worktree root path — a subdirectory path won't match and will error. git rev-parse --show-toplevel always returns the worktree root, regardless of where in the tree the shell is:

Suggested change

	git -C "$REPO" worktree remove "$(pwd)" # remove this worktree
	git -C "$REPO" worktree remove "$(git rev-parse --show-toplevel)" # remove this worktree

[d-morrison]

ARD Summary — round 2

#	Finding	Disposition	Notes
1	$(pwd) should be $(git rev-parse --show-toplevel) — git worktree remove requires the registered worktree root, not any subdirectory	✅ Addressed	Fixed

[claude]

Claude finished @d-morrison's task in 2m 10s —— View job

---

Code Review — Round 3

• Gather context
• Read changed file and diff
• Review for correctness, hallucinations, clarity, and style
• Post findings

---

All round-1 and round-2 findings are incorporated correctly. Here's the full verification:

REPO="$(git rev-parse --git-common-dir)/.." (line 73): Sound. Inside a linked worktree --git-common-dir returns the absolute path to the shared .git dir (e.g. /repo/.git), so /.. resolves to the main checkout root. Matches the comment. --git-common-dir exists since git 2.5.

git rev-parse --show-toplevel (line 74): Correct fix for the round-2 finding. Returns the registered worktree root regardless of subdirectory depth; git worktree remove requires the root, not a subdirectory. $(pwd) is gone.

Grammar (line 79): "hasn't" is correct. Round-1 fix applied.

git branch -D escape hatch (lines 82–84): The safety justification — step 1 already confirmed state == MERGED — is sound. A force-delete of the local branch cannot lose commits that have already landed in a merge commit on the remote. Round-1 finding properly handled.

Anti-pattern (line 150): Clean match to the diverged-main prose in step 2. No tension with the existing git branch -D anti-pattern two lines above (this one targets the pull/reset, not the delete).

No hallucinations. No AI-tell clusters. Prose is direct throughout.

Verdict: clean. Ready to merge.

[d-morrison]

Done — PR is clean and free.