Codex Review #193
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| name: Codex Review | |
| # Stage 2 of the two-stage Codex PR review. | |
| # | |
| # Triggered by the completion of Stage 1 (codex-review.yml) via `workflow_run`, | |
| # so it runs in the BASE repository context WITH access to secrets — even for | |
| # fork PRs. It NEVER checks out PR code: it only reads the pre-computed diff | |
| # artifact from Stage 1, so untrusted fork code can never execute next to the | |
| # OpenAI key. That structural guarantee is what makes reviewing fork PRs safe. | |
| # | |
| # Residual risk: Codex still reads the diff as *data*, so a prompt-injection | |
| # payload in the diff could in principle try to coax the key into a review | |
| # comment (the action keeps the key behind a proxy, but read-only Codex can reach | |
| # process memory). Use a scoped, low-limit OPENAI_API_KEY for this workflow. | |
| on: | |
| workflow_run: | |
| workflows: ["Codex Review (collect diff)"] | |
| types: [completed] | |
| permissions: | |
| contents: read | |
| concurrency: | |
| # Serialize per PR source (repo + branch), not per SHA, so a newer push cancels | |
| # an in-flight older review instead of racing it to post stale findings. | |
| group: codex-review-post-${{ github.event.workflow_run.head_repository.full_name }}-${{ github.event.workflow_run.head_branch }} | |
| cancel-in-progress: true | |
| jobs: | |
| review: | |
| if: github.event.workflow_run.conclusion == 'success' | |
| runs-on: ubuntu-latest | |
| permissions: | |
| contents: read | |
| actions: read # download-artifact needs this to read another run's artifact | |
| pull-requests: write # covers PR review comments AND the PR conversation comment | |
| steps: | |
| - name: Download Stage 1 diff artifact | |
| uses: actions/download-artifact@v4 | |
| with: | |
| name: codex-review-payload | |
| path: codex-payload | |
| run-id: ${{ github.event.workflow_run.id }} | |
| github-token: ${{ github.token }} | |
| - name: Resolve and verify PR | |
| id: pr | |
| uses: actions/github-script@v7 | |
| env: | |
| RUN_HEAD_SHA: ${{ github.event.workflow_run.head_sha }} | |
| with: | |
| github-token: ${{ github.token }} | |
| script: | | |
| const fs = require('fs'); | |
| const raw = fs.readFileSync('codex-payload/pr-number.txt', 'utf8').trim(); | |
| if (!/^\d+$/.test(raw)) { | |
| core.setFailed(`Invalid PR number in artifact: "${raw}"`); | |
| return; | |
| } | |
| const pull_number = Number(raw); | |
| const { owner, repo } = context.repo; | |
| const { data: pr } = await github.rest.pulls.get({ owner, repo, pull_number }); | |
| // Bind the artifact to a real PR: the triggering run's head_sha is set by | |
| // GitHub (not the fork), so requiring it to equal the PR head prevents a | |
| // tampered artifact from redirecting the review onto an unrelated PR. | |
| if (pr.head.sha !== process.env.RUN_HEAD_SHA) { | |
| core.setFailed( | |
| `PR #${pull_number} head ${pr.head.sha} != run head ${process.env.RUN_HEAD_SHA}; refusing to post.`, | |
| ); | |
| return; | |
| } | |
| // Re-apply Stage 1's gate against the PR's *current* state: it may have | |
| // been closed or converted to draft since the diff was collected. Keeps | |
| // posting behavior consistent with what gets reviewed. | |
| if (pr.state !== 'open' || pr.draft || pr.user?.type === 'Bot') { | |
| core.notice(`PR #${pull_number} is not an open, ready, human PR; skipping review.`); | |
| core.setOutput('skip', 'true'); | |
| return; | |
| } | |
| core.setOutput('skip', 'false'); | |
| core.setOutput('number', String(pull_number)); | |
| - name: Prepare working directory | |
| if: steps.pr.outputs.skip != 'true' | |
| run: | | |
| set -euo pipefail | |
| # codex-action runs `codex exec --cd <working-directory>`; give it a valid | |
| # (empty) git repo containing ONLY the diff — never any PR code. | |
| cd codex-payload | |
| # Allow an empty diff (e.g. a push reverted all changes) so the post step | |
| # still clears stale prior findings; only a missing file is an error. | |
| test -f pr.diff || { echo "pr.diff missing"; exit 1; } | |
| git init -q | |
| - name: Run Codex on the diff | |
| id: run_codex | |
| if: steps.pr.outputs.skip != 'true' | |
| # Pinned to the v1 commit SHA: this privileged job holds OPENAI_API_KEY, so a | |
| # moved/compromised tag must not silently change what runs here. | |
| uses: openai/codex-action@52fe01ec70a42f454c9d2ebd47598f9fd6893d56 # v1 | |
| with: | |
| openai-api-key: ${{ secrets.OPENAI_API_KEY }} | |
| # This job reviews ALL PRs incl. forks; the action's default write-access | |
| # gate would otherwise reject fork/non-collaborator authors. Safe to open | |
| # here because security comes from this job never checking out PR code | |
| # (only the diff artifact), not from the actor allowlist. | |
| allow-users: "*" | |
| model: gpt-5.5 | |
| effort: xhigh | |
| sandbox: read-only | |
| working-directory: codex-payload | |
| output-schema: | | |
| { | |
| "type": "object", | |
| "additionalProperties": false, | |
| "properties": { | |
| "summary": { "type": "string" }, | |
| "findings": { | |
| "type": "array", | |
| "items": { | |
| "type": "object", | |
| "additionalProperties": false, | |
| "properties": { | |
| "path": { "type": "string" }, | |
| "line": { "type": "integer" }, | |
| "severity": { "type": "string", "enum": ["blocking", "consider"] }, | |
| "comment": { "type": "string" } | |
| }, | |
| "required": ["path", "line", "severity", "comment"] | |
| } | |
| } | |
| }, | |
| "required": ["summary", "findings"] | |
| } | |
| prompt: | | |
| You are reviewing a pull request in ${{ github.repository }}. | |
| The complete set of changes is the unified diff in the file `pr.diff` in | |
| your working directory (run `cat pr.diff`). It is a `git diff` of | |
| base...head. Review ONLY those changes. Report high-signal findings only. | |
| Correctness & safety: | |
| - logic errors, unhandled edge cases, broken assumptions | |
| - security vulnerabilities | |
| - data loss, concurrency hazards, resource leaks | |
| Design & code quality: | |
| - the soundness of the overall approach, not just line-level bugs | |
| - elegance: is there a simpler, cleaner way to achieve the same result? | |
| - abstraction: prefer the most general clean abstraction that fits the problem, | |
| without over-engineering for cases that don't exist | |
| - redundancy: flag duplicated logic, dead code, and anything that violates DRY | |
| Skip pure formatting and style nits. | |
| Report at most the 5 most important findings. Consolidate an issue that | |
| recurs in several places into one finding at the most representative location. | |
| Output JSON matching the provided schema: | |
| - `summary`: one or two sentences on the PR overall. If there are no real | |
| issues, set summary to "No issues found." and findings to []. | |
| - `findings[].path`: repository-relative file path, exactly as it appears in | |
| the diff (the path after `+++ b/`). | |
| - `findings[].line`: the line number in the NEW (post-change) version of the | |
| file. It MUST be a line the PR adds or modifies. | |
| - `findings[].severity`: "blocking" or "consider". | |
| - `findings[].comment`: markdown review comment with a short code snippet and a | |
| concrete fix. | |
| - name: Post inline review | |
| if: steps.pr.outputs.skip != 'true' && steps.run_codex.outputs.final-message != '' | |
| uses: actions/github-script@v7 | |
| env: | |
| CODEX_RESULT: ${{ steps.run_codex.outputs.final-message }} | |
| PR_NUMBER: ${{ steps.pr.outputs.number }} | |
| REVIEWED_SHA: ${{ github.event.workflow_run.head_sha }} | |
| with: | |
| github-token: ${{ github.token }} | |
| script: | | |
| const { owner, repo } = context.repo; | |
| const pull_number = Number(process.env.PR_NUMBER); | |
| const SUMMARY_MARKER = '<!-- codex-review-summary -->'; | |
| const INLINE_MARKER = '<!-- codex-review-inline -->'; | |
| const MAX_COMMENTS = 5; | |
| const BOT = 'github-actions[bot]'; // only ever touch comments we authored | |
| // Parse Codex JSON. With --output-schema the result is already pure JSON, | |
| // and its findings may contain fenced code blocks, so never grab an inner | |
| // fence: parse the whole string first, then a fence wrapping the whole | |
| // string, then fall back to the outermost braces. | |
| function parseResult(raw) { | |
| if (!raw) return null; | |
| const tryParse = (s) => { try { return JSON.parse(s); } catch { return null; } }; | |
| const trimmed = raw.trim(); | |
| let out = tryParse(trimmed); | |
| if (out) return out; | |
| const fence = trimmed.match(/^```(?:json)?\s*\n?([\s\S]*?)\n?```$/); | |
| if (fence) { out = tryParse(fence[1].trim()); if (out) return out; } | |
| const a = trimmed.indexOf('{'), b = trimmed.lastIndexOf('}'); | |
| if (a !== -1 && b > a) return tryParse(trimmed.slice(a, b + 1)); | |
| return null; | |
| } | |
| const result = parseResult(process.env.CODEX_RESULT); | |
| if (!result) { core.setFailed('Could not parse Codex output as JSON.'); return; } | |
| const summary = (result.summary || '').trim(); | |
| const findings = (Array.isArray(result.findings) ? result.findings : []) | |
| .slice(0, MAX_COMMENTS); | |
| // Build the set of (path -> commentable new-file line numbers) from the diff. | |
| const pr = await github.rest.pulls.get({ owner, repo, pull_number }); | |
| const headSha = pr.data.head.sha; | |
| // If the PR advanced past the commit we reviewed, a newer run is already | |
| // handling the new head — don't post findings generated from a stale diff. | |
| if (headSha !== process.env.REVIEWED_SHA) { | |
| core.notice(`PR head moved ${process.env.REVIEWED_SHA} -> ${headSha}; skipping stale review.`); | |
| return; | |
| } | |
| const files = await github.paginate(github.rest.pulls.listFiles, { | |
| owner, repo, pull_number, per_page: 100, | |
| }); | |
| const commentable = new Map(); | |
| for (const f of files) { | |
| if (!f.patch) continue; | |
| const lines = new Set(); | |
| let newLine = 0; | |
| for (const ln of f.patch.split('\n')) { | |
| const h = ln.match(/^@@ -\d+(?:,\d+)? \+(\d+)(?:,\d+)? @@/); | |
| if (h) { newLine = parseInt(h[1], 10); continue; } | |
| if (ln.startsWith('\\')) continue; // "\ No newline at end of file" | |
| if (ln.startsWith('+')) { lines.add(newLine); newLine++; } | |
| else if (ln.startsWith('-')) { /* removed line, no new-side number */ } | |
| else { newLine++; } // context line | |
| } | |
| commentable.set(f.filename, lines); | |
| } | |
| // Split findings into inline-able vs. orphans (lines not in the diff). | |
| const inline = [], orphans = []; | |
| for (const fnd of findings) { | |
| const sev = (fnd.severity || 'consider').toUpperCase(); | |
| const set = commentable.get(fnd.path); | |
| if (set && set.has(fnd.line)) { | |
| inline.push({ | |
| path: fnd.path, line: fnd.line, side: 'RIGHT', | |
| body: `${INLINE_MARKER}\n**${sev}** ${fnd.comment}`, | |
| }); | |
| } else { | |
| orphans.push({ ...fnd, sev }); | |
| } | |
| } | |
| // Always clear our prior inline comments first, so findings resolved in a | |
| // later push disappear even when this run produces no inline comments. | |
| try { | |
| const prior = await github.paginate(github.rest.pulls.listReviewComments, { | |
| owner, repo, pull_number, per_page: 100, | |
| }); | |
| for (const c of prior) { | |
| if (c.user?.login === BOT && c.body && c.body.includes(INLINE_MARKER)) { | |
| try { await github.rest.pulls.deleteReviewComment({ owner, repo, comment_id: c.id }); } | |
| catch {} | |
| } | |
| } | |
| } catch (e) { core.warning(`Could not clean prior inline comments: ${e.message}`); } | |
| // Post this run's inline comments. If it fails, fold them into the summary. | |
| let inlinePosted = false; | |
| if (inline.length) { | |
| try { | |
| await github.rest.pulls.createReview({ | |
| owner, repo, pull_number, commit_id: headSha, | |
| event: 'COMMENT', comments: inline, | |
| }); | |
| inlinePosted = true; | |
| } catch (err) { | |
| core.warning(`Inline review failed (${err.status || ''}); folding into the summary.`); | |
| } | |
| } | |
| // Build the rolling summary comment. | |
| const leftover = inlinePosted | |
| ? orphans | |
| : findings.map(f => ({ ...f, sev: (f.severity || 'consider').toUpperCase() })); | |
| let body = `${SUMMARY_MARKER}\n### Codex review\n\n` + | |
| (summary || (findings.length ? 'See inline comments.' : 'No issues found.')); | |
| if (leftover.length) { | |
| body += `\n\n**${inlinePosted ? 'Findings not on changed lines' : 'Findings'}:**\n`; | |
| for (const o of leftover) body += `\n- \`${o.path}:${o.line}\` **${o.sev}** ${o.comment}`; | |
| } | |
| // Upsert one rolling summary comment instead of stacking on each push. | |
| const comments = await github.paginate(github.rest.issues.listComments, { | |
| owner, repo, issue_number: pull_number, per_page: 100, | |
| }); | |
| const existing = comments.find(c => c.user?.login === BOT && c.body && c.body.includes(SUMMARY_MARKER)); | |
| if (existing) { | |
| await github.rest.issues.updateComment({ owner, repo, comment_id: existing.id, body }); | |
| } else { | |
| await github.rest.issues.createComment({ owner, repo, issue_number: pull_number, body }); | |
| } |