fix(github): reject malformed repoFullName in app.ts and comments.ts

src/github/app.ts

@@ -437,14 +437,30 @@ export type GitHubRepositoryCollaboratorPermission =
   | "none"
   | string;
 
+// Parse `owner/repo` into its two segments, rejecting any shape that is not exactly two non-empty,
+// whitespace-free segments -- the identical guard every sibling GitHub-write module in this directory keeps
+// its own local copy of (assignees.ts / labels.ts / issues.ts / milestones.ts, per this dir's house
+// convention). "owner/repo/extra" would otherwise silently drop the extra segment and hit a different repo;
+// "owner/ repo" / " owner/repo" would get encodeURIComponent-ed straight into a GitHub URL. Returns null so
+// each caller can map a malformed value to its own established failure contract (return null / error object /
+// throw) rather than sharing one.
+function parseRepoFullNameStrict(repoFullName: string): { owner: string; repo: string } | null {
+  const parts = repoFullName.split("/");
+  const owner = parts[0];
+  const repo = parts[1];
+  if (parts.length !== 2 || !owner || !repo || /\s/.test(repoFullName)) return null;
+  return { owner, repo };
+}
+
 export async function getRepositoryCollaboratorPermission(
   env: Env,
   installationId: number,
   repoFullName: string,
   login: string,
 ): Promise<GitHubRepositoryCollaboratorPermission | null> {
-  const [owner, name] = repoFullName.split("/");
-  if (!owner || !name || !login) return null;
+  const parsed = parseRepoFullNameStrict(repoFullName);
+  if (!parsed || !login) return null;
+  const { owner, repo: name } = parsed;
   const token = await createInstallationToken(env, installationId);
   const response = await timeoutFetch(
     `https://api.github.com/repos/${encodeURIComponent(owner)}/${encodeURIComponent(name)}/collaborators/${encodeURIComponent(login)}/permission`,
@@ -617,8 +633,9 @@ export async function cancelInFlightWorkflowRunsForHeadSha(
   headSha: string,
   pullNumber: number,
 ): Promise<CancelWorkflowRunsOutcome> {
-  const [owner, repo] = repoFullName.split("/");
-  if (!owner || !repo) return { kind: "error", warning: `Invalid repository full name: ${repoFullName}` };
+  const parsed = parseRepoFullNameStrict(repoFullName);
+  if (!parsed) return { kind: "error", warning: `Invalid repository full name: ${repoFullName}` };
+  const { owner, repo } = parsed;
   const repoPath = `${encodeURIComponent(owner)}/${encodeURIComponent(repo)}`;
   try {
     const token = await createInstallationToken(env, installationId);
@@ -908,9 +925,9 @@ async function createOrUpdateNamedCheckRun(
   if (!advisory.headSha) return null;
   // Narrow once into a const so the postNewCheckRun closure below sees a string, not string | undefined.
   const headSha = advisory.headSha;
-  const [owner, repo] = repoFullName.split("/");
-  if (!owner || !repo)
-    throw new Error(`Invalid repository full name: ${repoFullName}`);
+  const parsed = parseRepoFullNameStrict(repoFullName);
+  if (!parsed) throw new Error(`Invalid repository full name: ${repoFullName}`);
+  const { owner, repo } = parsed;
 
   return await withInstallationTokenRetry(env, installationId, async (token) => {
     // makeInstallationOctokit injects the shared per-request timeout (a stalled PATCH can never orphan the

src/github/comments.ts

@@ -86,8 +86,11 @@ async function createOrUpdateIssueCommentWithMarker(
   const repo = parts[1];
   // Reject anything that is not exactly two non-empty segments -- "owner/repo/extra" would otherwise pass
   // (the destructure silently drops the extra segment), issuing a call against a repo the caller never
-  // specified. Matches the segment-count guard in parseRepoFullName (assignees.ts / labels.ts).
-  if (parts.length !== 2 || !owner || !repo) throw new Error(`Invalid repository full name: ${repoFullName}`);
+  // specified -- and additionally reject whitespace (`owner/ repo`, ` owner/repo`) so a padded slug can never
+  // reach a GitHub call. Matches the full segment-count + whitespace guard in parseRepoFullName
+  // (assignees.ts / labels.ts, #6613).
+  if (parts.length !== 2 || !owner || !repo || /\s/.test(repoFullName))
+    throw new Error(`Invalid repository full name: ${repoFullName}`);
 
   return await withInstallationTokenRetry(env, installationId, async (token) => {
     // Non-live mode suppresses the comment create/update writes; the GET marker-search probe below still runs.

test/unit/github-app.test.ts

@@ -2855,3 +2855,45 @@ describe("GitHub rate-limit handling (#ratelimit-resilience)", () => {
     expect(calls).toBe(4); // initial + GITHUB_RATE_LIMIT_MAX_RETRIES (3)
   });
 });
+
+describe("repoFullName segment-count + whitespace guard (#8311)", () => {
+  // Each of these malformed shapes must be rejected at every app.ts call site the same way the existing
+  // "invalid" (no-slash) case already is, matching the guard pr-actions.ts/assignees.ts/labels.ts share.
+  // The rejects happen before any GitHub call, so no fetch stub is needed. Inputs collectively exercise all
+  // four operands of the guard: parts.length !== 2 ("owner/repo/extra"), !owner ("/repo"), !repo ("owner/"),
+  // and the whitespace check ("owner/ repo", " owner/repo").
+  const MALFORMED = ["owner/repo/extra", "owner/ repo", " owner/repo", "/repo", "owner/"];
+
+  it("getRepositoryCollaboratorPermission returns null for extra-segment and whitespace-padded slugs", async () => {
+    const privateKey = await generatePrivateKeyPem();
+    const env = createTestEnv({ GITHUB_APP_PRIVATE_KEY: privateKey });
+    for (const repoFullName of MALFORMED) {
+      await expect(
+        getRepositoryCollaboratorPermission(env, 123, repoFullName, "maintainer"),
+      ).resolves.toBeNull();
+    }
+    // A well-formed slug still passes the guard (and only then fails downstream on the un-stubbed fetch).
+    await expect(
+      getRepositoryCollaboratorPermission(env, 123, "JSONbored/gittensory", "maintainer"),
+    ).rejects.toThrow();
+  });
+
+  it("cancelInFlightWorkflowRunsForHeadSha returns an error outcome for extra-segment and whitespace-padded slugs", async () => {
+    const privateKey = await generatePrivateKeyPem();
+    const env = createTestEnv({ GITHUB_APP_PRIVATE_KEY: privateKey });
+    for (const repoFullName of ["owner/repo/extra", "owner/ repo"]) {
+      const outcome = await cancelInFlightWorkflowRunsForHeadSha(env, 123, repoFullName, "abc123", 55);
+      expect(outcome).toEqual({ kind: "error", warning: `Invalid repository full name: ${repoFullName}` });
+    }
+  });
+
+  it("createOrUpdateCheckRun (createOrUpdateNamedCheckRun) throws for extra-segment and whitespace-padded slugs", async () => {
+    const privateKey = await generatePrivateKeyPem();
+    const env = createTestEnv({ GITHUB_APP_PRIVATE_KEY: privateKey });
+    for (const repoFullName of ["owner/repo/extra", "owner/ repo"]) {
+      await expect(
+        createOrUpdateCheckRun(env, 123, repoFullName, gateAdvisory("abc123")),
+      ).rejects.toThrow(`Invalid repository full name: ${repoFullName}`);
+    }
+  });
+});

test/unit/github-comments.test.ts

@@ -519,3 +519,19 @@ async function generatePrivateKeyPem(): Promise<string> {
   const base64 = Buffer.from(exported as ArrayBuffer).toString("base64").replace(/(.{64})/g, "$1\n");
   return `-----BEGIN PRIVATE KEY-----\n${base64}\n-----END PRIVATE KEY-----`;
 }
+
+describe("createOrUpdateIssueCommentWithMarker repoFullName guard (#8311)", () => {
+  // The existing segment-count guard now also rejects whitespace, matching pr-actions.ts/assignees.ts/
+  // labels.ts (#6613). These malformed shapes reject before any GitHub call (no fetch stub needed) and
+  // collectively exercise all four operands: parts.length !== 2 ("owner/repo/extra"), !owner ("/repo"),
+  // !repo ("owner/"), and the newly-added whitespace check ("owner/ repo", " owner/repo").
+  it("throws for extra-segment and whitespace-padded slugs", async () => {
+    const privateKey = await generatePrivateKeyPem();
+    const env = createTestEnv({ GITHUB_APP_PRIVATE_KEY: privateKey });
+    for (const repoFullName of ["owner/repo/extra", "/repo", "owner/", "owner/ repo", " owner/repo"]) {
+      await expect(
+        createOrUpdatePrIntelligenceComment(env, 123, repoFullName, 12, `${PR_INTELLIGENCE_COMMENT_MARKER}\nbody`),
+      ).rejects.toThrow(`Invalid repository full name: ${repoFullName}`);
+    }
+  });
+});