post-change-refactor

Development

Refactor and clean up the uncommitted change before committing. Eliminate duplication, rename unclear domain concepts, collapse shotgun surgery when another similar change is likely, remove dead / test-only / redundant code, split files larger than 250 lines into cohesive modules, and confirm related tests still pass. Use after finishing a phase or sub-phase and before commit, or whenever the developer asks to clean up the current change. Triggers on: refactor change, clean up change, post-change refactor, before commit cleanup, tidy current change.

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Source SKILL.md: https://github.com/terryyin/lizard/blob/HEAD/.cursor/skills/post-change-refactor/SKILL.md

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

Post-Change Refactor — Clean the Current Change Before Commit

When to use

After the implementation of a phase / sub-phase finishes and before the commit.
On demand, when the developer asks to clean up or refactor the current uncommitted change.

Start with .cursor/rules/ for project conventions and test practices.

Scope: "the current change"

The current change = files touched since the last commit (staged + unstaged

untracked). Discover the scope:

git status
git diff
git diff --cached

Git does not use the Nix prefix. All other repo tooling does.

All refactoring work is scoped to those files and the files that directly depend on them or are depended on by them. Do not sweep unrelated parts of the repo.

Decision boundary

Only keep code that is justified by the current change or by the immediate next phase in the plan (if one exists). Anything justified only by a phase further out, or by "we might need it later", is speculative — remove it.

If there is no plan, justification must come entirely from the current change.

Procedure

Run each check below in order. After all checks pass, hand control back to the caller — do not commit from inside this skill.

1. Duplication

Look for new duplication introduced by the change (copy-pasted blocks, parallel structures with cosmetic differences).
Look for duplication the change made visible — the new code repeats logic that already existed elsewhere.
The same concept appearing in two representations counts as duplication, not just literal copies.
Action: collapse onto a single representation. Prefer reusing an existing helper in the right layer (language reader, extension, shared tokenizer utility) over inventing a new one.

2. Domain naming

Read every new or renamed identifier — files, modules, classes, functions, variables, tests, fixtures.
Ask: does the name match what a domain reader expects? Does it match Lizard's language (complexity metrics, language readers, tokens, state machines, CCN, NLOC, etc.)?
Action: rename when intent is unclear, misleading, mixes layers, or leaks phase numbers / sequence info. Names describe capability, not development history.

3. Shotgun surgery

A change is shotgun surgery when one logical concept forces edits in many places.
Estimate the likelihood of another change of the same shape in the foreseeable future.
Action:
- High likelihood → consolidate the scattered edits behind a single seam (one function, one config, one module) so the next change touches one place. Do it now.
- Low likelihood → leave it. Do not preemptively abstract.

4. Dead / redundant / cancelling code

Remove aggressively whatever the change introduced or exposed that is not justified by the current change or the immediate next phase:

Code with no caller.
Branches that cannot be reached.
Pairs of edits that cancel each other (added then immediately worked around, flag toggles that never flip, etc.).
Production code only exercised by unit tests — no real caller from the CLI (lizard command), analyze_file API, language reader pipeline, or extension hook.
Unit tests that overlap with another test on the same observable surface (same input/output, same entry point).
Tests that pin internal structure rather than observable behavior — if a test mainly mirrors the code's factoring, drop it in favor of the test that drives a high-level entry point (analyze_file, analyze_source_code, CLI output).

When in doubt, delete. The next phase, if relevant, will reintroduce only what it actually needs.

5. File size

For every file touched by the change, check line count:

wc -l <path>

Files over 250 lines must be split. This rule is applied to test code as well.
Split along cohesive seams — one concept per module, not arbitrary line cuts.
Update imports. Keep the public API stable for callers outside the change.

6. Confirm related tests still pass

Run related tests for the changed files — not the whole suite. Use nix develop -c … for all commands below except git.

Area touched	Focused command
Core analyzer (`lizard.py`, `lizard_ext/`)	`nix develop -c python -m pytest test/test_analyzer.py test/testOutput.py` (add other top-level tests if those modules changed)
Language reader (`lizard_languages/`)	`nix develop -c python -m pytest test/test_languages/test<Lang>.py` for each affected language
Extension (`lizard_ext/`)	`nix develop -c python -m pytest test/test_extensions/test<Name>.py` for each affected extension
CLI / options	`nix develop -c python -m pytest test/testApplication.py test/test_options.py`
Broad or cross-cutting change	`nix develop -c python -m pytest`

Prefer analyze_file / analyze_source_code integration tests and CLI output tests over tests that only exercise internal helpers.

All related tests must pass before returning. If a test breaks because of the refactor (not the original change), fix it now.

Return

Report a short summary to the caller:

Which checks led to changes — duplication / naming / shotgun / dead code / file size.
Files renamed, extracted, split, or deleted.
Which related tests were run and confirmed passing.

Then hand control back. Do not commit from inside this skill — the caller commits.

Out of scope

Do not redesign code outside the changed files.
Do not start a new phase or add new behavior. Only restructure and remove.
Do not run the entire test suite or trigger CI from inside this skill unless the change is broad enough that focused tests cannot cover it.