fix(action): strip ANSI colors and fix diff mode on PRs

[bdsqqq]

fixes two bugs in the github action introduced in #63.

ANSI escape codes in PR comments

react-doctor uses picocolors for terminal output. the action pipes this through tee into a file, then posts it raw as a PR comment. ANSI codes (^[[32m, etc.) show up as literal text in the markdown code block.

fix: set NO_COLOR=1 in the env block. picocolors respects this natively — no stripping needed.

--diff mode falls back to full scan

actions/checkout checks out a detached HEAD merge commit on pull_request events. getCurrentBranch() in get-diff-files.ts:13 returns null for detached HEAD (branch === "HEAD" ? null : branch), causing getDiffInfo() to short-circuit at line 75 and fall back to a full scan.

fix: when diff input is set on a PR, checkout the actual head ref (github.head_ref) and fetch the base branch. this puts git on a real branch so getCurrentBranch() succeeds.

evidence

spotted in axiomhq/app#7259 — the action posted a comment with raw ANSI and ran a full scan instead of diffing.

— igor's agent

[vercel]

@bdsqqq is attempting to deploy a commit to the Million Team on Vercel.

A member of the Team first needs to authorize it.

[bdsqqq]

before/after from a real CI run

tested on a private monorepo (~800 tsx files) by pointing the action at this fix branch.

before (millionco/react-doctor@main):

• ANSI escapes leaked into PR comment (^[[32m, ^[[39m, etc.)
• diff mode ignored: "No feature branch or uncommitted changes detected. Running full scan." — scanned all files

react-doctor v0.0.29

^[[32m✔^[[39m Select projects to scan ^[[2m›^[[22m @axiomhq/console
^[[33mNo feature branch or uncommitted changes detected. Running full scan.^[[39m

^[[2mScanning /home/runner/work/app/app/apps/console...^[[22m

  ^[[31m✗^[[39m React Compiler can't optimize this code^[[31m (36)^[[39m
^[[2m    Todo: (BuildHIR::lowerExpression) Handle BigIntLiteral expressions^[[22m
  ... (hundreds of lines of findings across all files)

after (bdsqqq/react-doctor@fix/action-ansi-and-diff):

• clean text, no ANSI
• diff mode working: "Scanning changes: test/react-doctor-fix-verify → main"

react-doctor v0.0.29

✔ Select projects to scan › @axiomhq/console
Scanning changes: test/react-doctor-fix-verify → main

No changed source files in /home/runner/work/app/app/apps/console, skipping.

— igor's agent

[bdsqqq]

update: diff mode now fully working

previous comment showed ANSI fix working but diff mode was still broken — "No changed source files" even with source changes.

root cause: git fetch origin main stores the ref as FETCH_HEAD, not a local branch main. git merge-base main HEAD (used by react-doctor internally) fails with "Not a valid object name main". the bare catch {} in getChangedFilesSinceBranch silently returns [].

fix: git fetch origin "$BASE_REF":"$BASE_REF" — creates a local ref.

after (verified):

✔ Select projects to scan › @axiomhq/console
Scanning changes: test/react-doctor-diff-verify → main

Scanning /home/runner/work/app/app/apps/console...

  ✗ React Compiler can't optimize this code (2)
    Todo: (BuildHIR::lowerExpression) Handle BigIntLiteral expressions
    src/hubs/dash/components/traces/SpanDurationHeatmap.tsx: 26, 27

  99 / 100  Great
  ✗ 2 errors  across 1/1 files  in 784ms

only the touched file was scanned (1/1), only its findings shown. the broken full scan had 36+ findings across dozens of files.

— igor's agent

[bdsqqq]

note: fetch-depth requirement for diff mode

the diff step needs git merge-base which requires commit history. callers must use fetch-depth: 0 in their actions/checkout for diff mode to work. if they use the default (fetch-depth: 1), the action gracefully falls back to a full scan.

worth documenting in the README action usage section, something like:

# diff mode requires full git history
- uses: actions/checkout@v5
  with:
    fetch-depth: 0
- uses: millionco/react-doctor@main
  with:
    diff: main
    github-token: ${{ secrets.GITHUB_TOKEN }}

happy to add this to the README in a follow-up PR if you want.

— igor's agent