Merge Base Branch

Merge the chosen base branch into the current branch and finish with a clean lint, full test coverage, and successful build. Use when you want the branch fully reconciled with its parent and CI-quality checks passing locally.

Usage:

• /merge-base-branch — Run the full workflow below

Prerequisites:

• Repository root must be a git checkout on a named branch (not detached HEAD).
• If the project uses Node/npm, package.json must define scripts lint, test:coverage, and build. If package.json is missing or any of those scripts is missing, report what is absent and STOP (do not merge or proceed without the mandated checks).

Instructions:

1. Current branch:

   • Run git branch --show-current. If detached HEAD, inform the user and STOP.

2. Determine base branch candidate, then let the user choose:

   • First, if .agent exists at the repo root, read it for baseBranch=<value>. That value is the detected candidate (if present).
   • Else, infer from git: run git merge-base --fork-point main HEAD, git merge-base --fork-point master HEAD, and git merge-base --fork-point develop HEAD. Any branch name that returns a commit is a match. If exactly one matches, that is the detected candidate. If several match, choose by priority: main, then master, then develop. If none match, detected candidate is unset.
   • Use AskUserQuestion so the user picks the base branch to merge. Always include main as an option. Include the detected candidate as an option when it is set and differs from main. Include master and develop as additional options when they exist on origin (or locally). Include a short label on each option (e.g. “Detected from history: develop”). Wait for the answer; the selected branch is <base-branch>.

3. Verify base branch and fetch:

   • Confirm with git rev-parse --verify origin/<base-branch> or, failing that, git rev-parse --verify <base-branch>. If neither exists, inform the user and STOP.
   • Run git fetch origin <base-branch>. On failure, show the error and STOP.

4. Stop if already up to date with the base:

   • Let <merge-ref> be origin/<base-branch> when that ref exists after fetch; otherwise <base-branch> (local only).
   • Run git rev-list --count HEAD..<merge-ref> (or equivalent: no commits in git log --oneline HEAD..<merge-ref>).
   • If the count is 0, inform the user that the current branch already contains everything from <merge-ref> and no merge is needed. If the working tree is not clean, note that uncommitted changes remain. STOP (do not commit WIP for this workflow, merge, or run lint/tests/build).

5. Commit all uncommitted work before merge:

   • If git status shows no unstaged/staged/untracked changes that need committing, skip to step 6.
   • Otherwise stage and commit everything in the working tree (not limited to files touched in the current session). Split into multiple commits when the diff clearly contains separate logical chunks (e.g. group by feature area or directory); each commit gets a clear message. Use git add selectively (or git add -p) to build coherent commits—do not squash unrelated work into one commit when multiple distinct chunks exist.

6. Merge base branch:

   • Run git merge origin/<base-branch> --no-edit (use git merge <base-branch> --no-edit only if there is no origin/<base-branch> but the local branch exists).
   • If the merge succeeds, summarize merged commits briefly.

7. Resolve conflicts and conclude merge:

   • On conflicts: list with git diff --name-only --diff-filter=U, resolve each file (remove conflict markers; combine or choose per intent—prefer base for upstream fixes, keep branch work for feature code), git add each resolved file, then git merge --continue --no-edit until the merge completes.

8. Lint:

   • From repo root, run npm run lint. Fix all reported issues; re-run until it passes.

9. Commit after lint (if anything changed):

   • If lint fixes (or formatter churn) changed files, commit with an appropriate message (one or more commits if chunks warrant it).

10. Tests with coverage:

    • Run npm run test:coverage. If it fails, read the coverage report and any failure output; add or adjust tests until all lines are covered at 100% (per project/tooling). Re-run and iterate until the command succeeds.

11. Commit test/coverage changes:

    • Commit any test or source changes from step 10 with a clear message.

12. Build:

    • Run npm run build. Fix compile/bundler errors; re-run until it passes.

13. Commit build fixes (if any):

    • Commit if step 12 produced file changes.

Summary for the user: base branch used, merge result (or “already up to date”), lint/test/build outcomes, and list of commits created during the run.