feat: add atomic PR check workflow #6
Workflow file for this run
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| name: Atomic PR Check | |
| on: | |
| pull_request: | |
| types: [opened, edited, synchronize, reopened] | |
| branches: | |
| - main | |
| permissions: | |
| contents: read | |
| pull-requests: write | |
| jobs: | |
| atomic-check: | |
| name: Atomic PR Check | |
| runs-on: ubuntu-latest | |
| # Skip automated dependency update bots — they always produce atomic PRs by definition | |
| if: ${{ github.actor != 'dependabot[bot]' && github.actor != 'renovate[bot]' }} | |
| steps: | |
| - name: Analyse PR atomicity | |
| uses: actions/github-script@v7 | |
| with: | |
| github-token: ${{ secrets.GITHUB_TOKEN }} | |
| script: | | |
| const owner = context.repo.owner; | |
| const repo = context.repo.repo; | |
| const pr = context.payload.pull_request; | |
| const prNumber = pr.number; | |
| // ────────────────────────────────────────────────────────────── | |
| // Fetch all changed files (handles pagination automatically) | |
| // ────────────────────────────────────────────────────────────── | |
| const files = await github.paginate(github.rest.pulls.listFiles, { | |
| owner, repo, pull_number: prNumber, per_page: 100, | |
| }); | |
| const violations = []; | |
| const warnings = []; | |
| // ────────────────────────────────────────────────────────────── | |
| // Check 1 — PR title contains "and" | |
| // Rationale: a title that needs "and" almost always covers two | |
| // concerns. This is the fastest signal from the Atomic PR doc. | |
| // ────────────────────────────────────────────────────────────── | |
| if (/\band\b/i.test(pr.title)) { | |
| violations.push( | |
| `**PR title contains "and":** \`${pr.title}\`\n` + | |
| ` → If the title requires "and", the PR likely covers multiple concerns. ` + | |
| `Split it so each PR has a single, unambiguous purpose.` | |
| ); | |
| } | |
| // ────────────────────────────────────────────────────────────── | |
| // Check 2 — Number of changed files | |
| // Thresholds are intentionally conservative for an SDK codebase. | |
| // ────────────────────────────────────────────────────────────── | |
| const FILE_WARN = 15; | |
| const FILE_VIOLATION = 40; | |
| const fileCount = files.length; | |
| if (fileCount >= FILE_VIOLATION) { | |
| violations.push( | |
| `**Too many files changed:** ${fileCount} files (hard limit: ${FILE_VIOLATION}).\n` + | |
| ` → Reviewers cannot audit this thoroughly. Break it into smaller, focused PRs.` | |
| ); | |
| } else if (fileCount >= FILE_WARN) { | |
| warnings.push( | |
| `**Many files changed:** ${fileCount} files — verify every file is strictly required ` + | |
| `for this single concern.` | |
| ); | |
| } | |
| // ────────────────────────────────────────────────────────────── | |
| // Check 3 — Total line-change volume | |
| // ────────────────────────────────────────────────────────────── | |
| const LINE_WARN = 400; | |
| const LINE_VIOLATION = 1500; | |
| const additions = files.reduce((s, f) => s + f.additions, 0); | |
| const deletions = files.reduce((s, f) => s + f.deletions, 0); | |
| const totalLines = additions + deletions; | |
| if (totalLines >= LINE_VIOLATION) { | |
| violations.push( | |
| `**Very large diff:** +${additions} / -${deletions} (${totalLines} total lines).\n` + | |
| ` → A diff this size makes thorough review impractical. Consider splitting.` | |
| ); | |
| } else if (totalLines >= LINE_WARN) { | |
| warnings.push( | |
| `**Large diff:** +${additions} / -${deletions} (${totalLines} lines) — ` + | |
| `ensure reviewers can audit every changed line.` | |
| ); | |
| } | |
| // ────────────────────────────────────────────────────────────── | |
| // Check 4 — Renames / moves mixed with logic changes | |
| // Rationale: structural changes (PR A) should precede logic | |
| // changes (PR B) so each is trivially verifiable. | |
| // ────────────────────────────────────────────────────────────── | |
| const renamedFiles = files.filter(f => f.status === 'renamed'); | |
| const modifiedFiles = files.filter(f => f.status === 'modified' || f.status === 'changed'); | |
| if (renamedFiles.length > 0 && modifiedFiles.length > 0) { | |
| const renamedList = renamedFiles.map(f => `\`${f.filename}\``).join(', '); | |
| warnings.push( | |
| `**Structural and logic changes mixed:** ${renamedFiles.length} renamed/moved ` + | |
| `file(s) alongside ${modifiedFiles.length} modified file(s).\n` + | |
| ` → Renamed files: ${renamedList}\n` + | |
| ` → Per atomic PR guidelines, do the rename in a dedicated PR first, ` + | |
| `then apply logic changes on top.` | |
| ); | |
| } | |
| // ────────────────────────────────────────────────────────────── | |
| // Check 5 — Formatting / linting config files mixed with source | |
| // Rationale: formatting noise hides real changes and makes the | |
| // diff harder to audit. | |
| // ────────────────────────────────────────────────────────────── | |
| const isFormattingConfig = f => { | |
| const name = f.filename.toLowerCase(); | |
| return ( | |
| /\.(eslint|prettier|stylelint|editorconfig)/.test(name) || | |
| name.endsWith('.config.js') || | |
| name.endsWith('.config.ts') || | |
| name.endsWith('.config.mjs') || | |
| name === '.prettierrc' || | |
| name === '.editorconfig' | |
| ); | |
| }; | |
| const configFiles = files.filter(isFormattingConfig); | |
| const srcFiles = files.filter(f => f.filename.startsWith('src/')); | |
| if (configFiles.length > 0 && srcFiles.length > 0) { | |
| const configList = configFiles.map(f => `\`${f.filename}\``).join(', '); | |
| warnings.push( | |
| `**Formatting/config changes mixed with source changes:** ${configList}\n` + | |
| ` → Linting or formatting changes add noise to a logic diff. ` + | |
| `Move them to a separate, instantly-reviewable PR.` | |
| ); | |
| } | |
| // ────────────────────────────────────────────────────────────── | |
| // Check 6 — Scope spread across unrelated top-level areas | |
| // ────────────────────────────────────────────────────────────── | |
| const TRACKED_SCOPES = ['src', '__tests__', 'cypress', 'scripts', '.github']; | |
| const SCOPE_WARN = 3; | |
| const touchedScopes = [ | |
| ...new Set( | |
| files | |
| .map(f => f.filename.split('/')[0]) | |
| .filter(d => TRACKED_SCOPES.includes(d)) | |
| ) | |
| ]; | |
| // src + __tests__ together is expected; only flag when additional | |
| // unrelated areas (CI config, scripts, cypress, …) are also touched. | |
| const unexpectedScopes = touchedScopes.filter( | |
| s => s !== 'src' && s !== '__tests__' | |
| ); | |
| const sourceAndTestOnly = | |
| touchedScopes.includes('src') && unexpectedScopes.length === 0; | |
| if (!sourceAndTestOnly && touchedScopes.length > SCOPE_WARN) { | |
| warnings.push( | |
| `**Wide scope:** changes span ${touchedScopes.length} major areas: ` + | |
| `\`${touchedScopes.join('`, `')}\`.\n` + | |
| ` → Verify that touching all these areas is strictly required for ` + | |
| `this single contribution.` | |
| ); | |
| } | |
| // ────────────────────────────────────────────────────────────── | |
| // Build the comment body | |
| // ────────────────────────────────────────────────────────────── | |
| const hasViolations = violations.length > 0; | |
| const hasWarnings = warnings.length > 0; | |
| let commentBody; | |
| if (!hasViolations && !hasWarnings) { | |
| commentBody = [ | |
| '## Atomic PR Check — Passed ✓', | |
| '', | |
| 'No atomicity concerns found. This PR looks well-scoped.', | |
| ].join('\n'); | |
| } else { | |
| const lines = ['## Atomic PR Check']; | |
| if (hasViolations) { | |
| lines.push( | |
| '', | |
| '### Violations', | |
| '_These must be addressed before the PR is ready for review._', | |
| '' | |
| ); | |
| violations.forEach(v => lines.push(`- ${v}`, '')); | |
| } | |
| if (hasWarnings) { | |
| lines.push( | |
| '', | |
| '### Warnings', | |
| '_Advisory — reviewers are empowered to request changes if these ' + | |
| 'concerns affect auditability._', | |
| '' | |
| ); | |
| warnings.forEach(w => lines.push(`- ${w}`, '')); | |
| } | |
| lines.push( | |
| '', | |
| '---', | |
| '_Powered by the Atomic PR guidelines. ' + | |
| 'Reviewers are expected to refuse reviews for PRs that are not set up for easy auditing._' | |
| ); | |
| commentBody = lines.join('\n'); | |
| } | |
| // ────────────────────────────────────────────────────────────── | |
| // Post or update the bot comment (idempotent on re-runs) | |
| // ────────────────────────────────────────────────────────────── | |
| const MARKER = '<!-- atomic-pr-check-v1 -->'; | |
| const body = `${MARKER}\n${commentBody}`; | |
| const { data: existingComments } = await github.rest.issues.listComments({ | |
| owner, repo, issue_number: prNumber, | |
| }); | |
| const existingComment = existingComments.find( | |
| c => c.body.startsWith(MARKER) | |
| ); | |
| if (existingComment) { | |
| await github.rest.issues.updateComment({ | |
| owner, repo, comment_id: existingComment.id, body, | |
| }); | |
| } else { | |
| await github.rest.issues.createComment({ | |
| owner, repo, issue_number: prNumber, body, | |
| }); | |
| } | |
| // ────────────────────────────────────────────────────────────── | |
| // Fail the workflow step when hard violations are present. | |
| // Add this check to branch protection rules to enforce it. | |
| // ────────────────────────────────────────────────────────────── | |
| if (hasViolations) { | |
| core.setFailed( | |
| `Atomic PR check found ${violations.length} violation(s). See the PR comment for details.` | |
| ); | |
| } |