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fix: pin adversarial branch review context to commit revisions #840

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a3c03d9
fix: pin adversarial branch review context to commit revisions
Linxiushen Nov 9, 2026
4ed3792
fix: pin branch review content and peel base tags
Linxiushen Nov 11, 2026
8151d49
fix: pin surrounding reads for inline branch reviews
Linxiushen Nov 11, 2026
24fcd19
fix: bind branch comparison to captured branch ref
Linxiushen Nov 13, 2026
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29 changes: 18 additions & 11 deletions plugins/codex/scripts/lib/git.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -66,12 +66,16 @@ function measureCombinedGitOutputBytes(cwd, argSets, maxBytes) {
return totalBytes;
}

function buildBranchComparison(cwd, baseRef) {
const mergeBase = gitChecked(cwd, ["merge-base", "HEAD", baseRef]).stdout.trim();
function buildBranchComparison(cwd, baseRef, currentBranch = "HEAD") {
const headRef = currentBranch === "HEAD" ? "HEAD" : `refs/heads/${currentBranch}`;
const headCommit = gitChecked(cwd, ["rev-parse", "--verify", "--end-of-options", `${headRef}^{commit}`]).stdout.trim();
const baseCommit = gitChecked(cwd, ["rev-parse", "--verify", "--end-of-options", `${baseRef}^{commit}`]).stdout.trim();
const mergeBase = gitChecked(cwd, ["merge-base", headCommit, baseCommit]).stdout.trim();
return {
headCommit,
mergeBase,
commitRange: `${mergeBase}..HEAD`,
reviewRange: `${baseRef}...HEAD`
commitRange: `${mergeBase}..${headCommit}`,
reviewRange: `${baseCommit}...${headCommit}`
};
}

Expand Down Expand Up @@ -261,8 +265,8 @@ function collectWorkingTreeContext(cwd, state, options = {}) {

function collectBranchContext(cwd, baseRef, options = {}) {
const includeDiff = options.includeDiff !== false;
const comparison = options.comparison ?? buildBranchComparison(cwd, baseRef);
const currentBranch = getCurrentBranch(cwd);
const currentBranch = options.currentBranch ?? getCurrentBranch(cwd);
const comparison = options.comparison ?? buildBranchComparison(cwd, baseRef, currentBranch);
const changedFiles = gitChecked(cwd, ["diff", "--name-only", comparison.commitRange]).stdout.trim().split("\n").filter(Boolean);
const logOutput = gitChecked(cwd, ["log", "--oneline", "--decorate", comparison.commitRange]).stdout.trim();
const diffStat = gitChecked(cwd, ["diff", "--stat", comparison.commitRange]).stdout.trim();
Expand Down Expand Up @@ -290,11 +294,14 @@ function collectBranchContext(cwd, baseRef, options = {}) {
}

function buildAdversarialCollectionGuidance(options = {}) {
const pinnedRange = options.comparison
? ` For this branch review, use the pinned commit range ${options.comparison.commitRange}. Read surrounding file content with \`git show ${options.comparison.headCommit}:<path>\`; the working tree may belong to a different branch.`
: "";
if (options.includeDiff !== false) {
return "Use the repository context below as primary evidence.";
return `Use the repository context below as primary evidence.${pinnedRange}`;
}

return "The repository context below is a lightweight summary. Inspect the target diff yourself with read-only git commands before finalizing findings.";
return `The repository context below is a lightweight summary. Inspect the target diff yourself with read-only git commands before finalizing findings.${pinnedRange}`;
}

export function collectReviewContext(cwd, target, options = {}) {
Expand Down Expand Up @@ -322,15 +329,15 @@ export function collectReviewContext(cwd, target, options = {}) {
diffBytes <= maxInlineDiffBytes);
details = collectWorkingTreeContext(repoRoot, state, { includeDiff });
} else {
const comparison = buildBranchComparison(repoRoot, target.baseRef);
const comparison = buildBranchComparison(repoRoot, target.baseRef, currentBranch);
const fileCount = gitChecked(repoRoot, ["diff", "--name-only", comparison.commitRange]).stdout.trim().split("\n").filter(Boolean).length;
diffBytes = measureGitOutputBytes(
repoRoot,
["diff", "--binary", "--no-ext-diff", "--submodule=diff", comparison.commitRange],
maxInlineDiffBytes
);
includeDiff = options.includeDiff ?? (fileCount <= maxInlineFiles && diffBytes <= maxInlineDiffBytes);
details = collectBranchContext(repoRoot, target.baseRef, { includeDiff, comparison });
details = collectBranchContext(repoRoot, target.baseRef, { includeDiff, comparison, currentBranch });

@chatgpt-codex-connector chatgpt-codex-connector Bot Nov 11, 2026

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P2 Badge Tie the branch label to the pinned HEAD

When another process checks out branch B after getCurrentBranch(repoRoot) captures branch A but before buildBranchComparison resolves HEAD, comparison.headCommit and the pinned diff come from B while this call passes A into collectBranchContext. The returned context therefore says Reviewing branch A for a review of B (and persists that metadata in JSON), so background review results can be attributed to the wrong change; resolve the captured branch ref to its commit, or capture the label and OID consistently.

Useful? React with 👍 / 👎.

}

return {
Expand All @@ -341,7 +348,7 @@ export function collectReviewContext(cwd, target, options = {}) {
fileCount: details.changedFiles.length,
diffBytes,
inputMode: includeDiff ? "inline-diff" : "self-collect",
collectionGuidance: buildAdversarialCollectionGuidance({ includeDiff }),
collectionGuidance: buildAdversarialCollectionGuidance({ includeDiff, comparison: details.comparison }),
...details
};
}
113 changes: 113 additions & 0 deletions tests/git.test.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,10 +2,123 @@ import fs from "node:fs";
import path from "node:path";
import test from "node:test";
import assert from "node:assert/strict";
import childProcess from "node:child_process";
import { syncBuiltinESMExports } from "node:module";

import { collectReviewContext, resolveReviewTarget } from "../plugins/codex/scripts/lib/git.mjs";
import { initGitRepo, makeTempDir, run } from "./helpers.mjs";

for (const [mode, options] of [["inline", {}], ["lightweight", { maxInlineFiles: 0 }]]) {
for (const switchPoint of ["after comparison", "after branch label"]) {
test(`branch review keeps one commit snapshot during ${mode} collection ${switchPoint}`, (t) => {
const cwd = makeTempDir();
const git = (args) => {
const result = run("git", args, { cwd, shell: false });
assert.equal(result.status, 0, result.stderr);
return result.stdout.trim();
};
initGitRepo(cwd);
fs.writeFileSync(path.join(cwd, "base.js"), "export const base = true;\n");
git(["add", "."]);
git(["commit", "-m", "base"]);
git(["checkout", "-b", "feature/reviewed"]);
fs.writeFileSync(path.join(cwd, "reviewed.js"), "export const value = 'REVIEWED_CHANGE';\n");
git(["add", "."]);
git(["commit", "-m", "reviewed change"]);
const reviewedHead = git(["rev-parse", "HEAD"]);
git(["checkout", "-b", "feature/other"]);
fs.writeFileSync(path.join(cwd, "reviewed.js"), "export const value = 'OTHER_BRANCH_CONTEXT';\n");
fs.writeFileSync(path.join(cwd, "other.js"), "export const value = 'OTHER_BRANCH_CHANGE';\n");
git(["add", "."]);
git(["commit", "-m", "other branch change"]);
git(["checkout", "feature/reviewed"]);
git(["tag", "feature/reviewed", "feature/other"]);

const spawnSync = childProcess.spawnSync;
let switched = false;
t.mock.method(childProcess, "spawnSync", (command, args, commandOptions) => {
const result = spawnSync(command, args, commandOptions);
if (!switched && command === "git" && (switchPoint === "after comparison"
? args[0] === "diff" && args[1] === "--name-only"
: args[0] === "branch" && args[1] === "--show-current")) {
switched = true;
const checkout = spawnSync("git", ["checkout", "feature/other"], {
cwd, encoding: "utf8", shell: false, windowsHide: true
});
assert.equal(checkout.status, 0, checkout.stderr);
if (switchPoint === "after comparison") {
const updateBase = spawnSync("git", ["update-ref", "refs/heads/main", "HEAD"], {
cwd, encoding: "utf8", shell: false, windowsHide: true
});
assert.equal(updateBase.status, 0, updateBase.stderr);
}
}
return result;
});
syncBuiltinESMExports();
t.after(() => {
t.mock.restoreAll();
syncBuiltinESMExports();
});

const context = collectReviewContext(cwd, { mode: "branch", baseRef: "main" }, options);

assert.equal(switched, true);
assert.equal(git(["branch", "--show-current"]), "feature/other");
assert.deepEqual(context.changedFiles, ["reviewed.js"]);
assert.equal(git(["diff", "--name-only", context.comparison.reviewRange]), "reviewed.js");
assert.equal(context.branch, "feature/reviewed");
assert.match(context.summary, /Reviewing branch feature\/reviewed /);
assert.doesNotMatch(context.content, /other branch change|other\.js|OTHER_BRANCH_CHANGE|OTHER_BRANCH_CONTEXT/);
assert.match(fs.readFileSync(path.join(cwd, "reviewed.js"), "utf8"), /OTHER_BRANCH_CONTEXT/);
assert.ok(context.collectionGuidance.includes(context.comparison.commitRange));
assert.ok(context.collectionGuidance.includes(`git show ${reviewedHead}:<path>`));
assert.equal(context.comparison.headCommit, reviewedHead);
assert.match(git(["show", `${context.comparison.headCommit}:reviewed.js`]), /REVIEWED_CHANGE/);
assert.doesNotMatch(git(["show", `${context.comparison.headCommit}:reviewed.js`]), /OTHER_BRANCH_CONTEXT/);
if (mode === "inline") {
assert.match(context.content, /REVIEWED_CHANGE/);
}
});
}
}

for (const detached of [false, true]) {
test(`branch review peels annotated base tags to commit snapshots (${detached ? "detached" : "attached"})`, () => {
const cwd = makeTempDir();
const git = (args) => {
const result = run("git", args, { cwd, shell: false });
assert.equal(result.status, 0, result.stderr);
return result.stdout.trim();
};
initGitRepo(cwd);
fs.writeFileSync(path.join(cwd, "app.js"), "console.log('base');\n");
git(["add", "."]);
git(["commit", "-m", "base"]);
const baseCommit = git(["rev-parse", "HEAD"]);
git(["tag", "-a", "review-base", "-m", "annotated base"]);
const tagObject = git(["rev-parse", "review-base"]);
assert.notEqual(tagObject, baseCommit);
assert.equal(git(["cat-file", "-t", tagObject]), "tag");
git(["checkout", "-b", "feature/reviewed"]);
fs.writeFileSync(path.join(cwd, "app.js"), "console.log('reviewed');\n");
git(["add", "."]);
git(["commit", "-m", "reviewed change"]);
const headCommit = git(["rev-parse", "HEAD"]);
if (detached) git(["checkout", "--detach", headCommit]);

const context = collectReviewContext(cwd, { mode: "branch", baseRef: "review-base" }, { maxInlineFiles: 0 });

assert.equal(context.branch, detached ? "HEAD" : "feature/reviewed");
assert.equal(context.comparison.headCommit, headCommit);
assert.equal(context.comparison.reviewRange, `${baseCommit}...${headCommit}`);
assert.equal(context.comparison.commitRange, `${baseCommit}..${headCommit}`);
assert.equal(git(["cat-file", "-t", context.comparison.reviewRange.split("...")[0]]), "commit");
assert.equal(git(["diff", "--name-only", context.comparison.reviewRange]), "app.js");
});

}

test("resolveReviewTarget prefers working tree when repo is dirty", () => {
const cwd = makeTempDir();
initGitRepo(cwd);
Expand Down