dsyme · Jun 7, 2026 · Jun 7, 2026 · Jun 7, 2026 · Jun 7, 2026
diff --git a/.changeset/patch-find-repo-checkout-manifest-first.md b/.changeset/patch-find-repo-checkout-manifest-first.md
diff --git a/actions/setup/js/checkout_manifest.cjs b/actions/setup/js/checkout_manifest.cjs
@@ -93,7 +93,27 @@ function _resetCache() {
   cached = null;
 }
 
+/**
+ * Return all checkout manifest entries as a Map keyed by lowercase repo slug.
+ * Each value has the shape { repository, path, default_branch }.
+ *
+ * @returns {Map<string, { repository: string, path: string, default_branch: string }>}
+ */
+function loadAllCheckouts() {
+  const manifest = loadManifest();
+  const map = new Map();
+  for (const [key, entry] of Object.entries(manifest)) {
+    if (!entry || typeof entry !== "object") continue;
+    const repository = typeof entry.repository === "string" ? entry.repository : key;
+    const entryPath = typeof entry.path === "string" ? entry.path : "";
+    const defaultBranch = typeof entry.default_branch === "string" ? entry.default_branch : "";
+    map.set(key, { repository, path: entryPath, default_branch: defaultBranch });
+  }
+  return map;
+}
+
 module.exports = {
   lookupCheckout,
+  loadAllCheckouts,
   _resetCache,
 };
diff --git a/actions/setup/js/find_repo_checkout.cjs b/actions/setup/js/find_repo_checkout.cjs
@@ -4,6 +4,7 @@ const fs = require("fs");
 const path = require("path");
 const { execGitSync } = require("./git_helpers.cjs");
 const { validateTargetRepo, parseAllowedRepos, getDefaultTargetRepo } = require("./repo_helpers.cjs");
+const { lookupCheckout, loadAllCheckouts } = require("./checkout_manifest.cjs");
 
 /**
  * Debug logging helper - logs to stderr when DEBUG env var matches
@@ -122,6 +123,24 @@ function getRemoteOriginUrl(repoPath) {
   }
 }
 
+/**
+ * Resolve a workspace-relative path from the checkout manifest into an
+ * absolute path under the workspace. The manifest stores an empty string
+ * to represent the workspace root.
+ * @param {string} workspaceRoot
+ * @param {string} relPath
+ * @returns {string}
+ */
+function resolveManifestPath(workspaceRoot, relPath) {
+  if (!relPath || relPath === "" || relPath === ".") {
+    return workspaceRoot;
+  }
+  if (path.isAbsolute(relPath)) {
+    return relPath;
+  }
+  return path.join(workspaceRoot, relPath);
+}
+
 /**
  * Find the checkout directory for a given repo slug
  * Searches the workspace for git repos and matches by remote URL
@@ -155,6 +174,22 @@ function findRepoCheckout(repoSlug, workspaceRoot, options = {}) {
     }
   }
 
+  // First, consult the checkout manifest written by the compiler-emitted
+  // "Build checkout manifest for safe-outputs handlers" step. This is the
+  // authoritative source for cross-repo checkout paths and does not depend
+  // on `git config --get remote.origin.url`, which a later "Configure Git
+  // credentials" step may have overwritten to point at the workflow repo.
+  const manifestEntry = lookupCheckout(targetSlug);
+  if (manifestEntry) {
+    const resolved = resolveManifestPath(ws, manifestEntry.path);
+    debugLog(`Found manifest entry for ${targetSlug}: ${resolved}`);
+    return {
+      success: true,
+      path: resolved,
+      repoSlug: targetSlug,
+    };
+  }
+
   // Find all git directories in the workspace
   const gitDirs = findGitDirectories(ws);
   debugLog(`Found ${gitDirs.length} git directories: ${gitDirs.join(", ")}`);
@@ -211,14 +246,21 @@ function buildRepoCheckoutMap(workspaceRoot) {
   const ws = workspaceRoot || process.env.GITHUB_WORKSPACE || process.cwd();
   const map = new Map();
 
+  // Seed from the checkout manifest first so cross-repo entries survive even
+  // when a later "Configure Git credentials" step has rewritten remote.origin.url.
+  const manifest = loadAllCheckouts();
+  for (const [slug, entry] of manifest) {
+    map.set(slug, resolveManifestPath(ws, entry.path));
+  }
+
   const gitDirs = findGitDirectories(ws);
 
   for (const repoPath of gitDirs) {
     const remoteUrl = getRemoteOriginUrl(repoPath);
     if (!remoteUrl) continue;
 
     const slug = extractRepoSlugFromUrl(remoteUrl);
-    if (slug) {
+    if (slug && !map.has(slug)) {
       map.set(slug, repoPath);
     }
   }

diff --git a/actions/setup/js/find_repo_checkout.test.cjs b/actions/setup/js/find_repo_checkout.test.cjs
@@ -2,6 +2,7 @@ const fs = require("fs");
 const path = require("path");
 const { extractRepoSlugFromUrl, normalizeRepoSlug, findGitDirectories, findRepoCheckout, buildRepoCheckoutMap } = require("./find_repo_checkout.cjs");
 const { getPatchPathForBranchInRepo, sanitizeBranchNameForPatch, sanitizeRepoSlugForPatch } = require("./generate_git_patch.cjs");
+const { _resetCache: resetCheckoutManifestCache } = require("./checkout_manifest.cjs");
 
 describe("find_repo_checkout", () => {
   describe("extractRepoSlugFromUrl", () => {
@@ -168,6 +169,140 @@ describe("find_repo_checkout", () => {
     });
   });
 
+  describe("checkout manifest fallback (issue #37545)", () => {
+    let workspaceDir;
+    let manifestPath;
+    let originalManifestEnv;
+
+    beforeEach(() => {
+      originalManifestEnv = process.env.GH_AW_CHECKOUT_MANIFEST;
+      workspaceDir = fs.mkdtempSync(path.join(require("os").tmpdir(), "test-manifest-"));
+      manifestPath = path.join(workspaceDir, "checkout-manifest.json");
+      process.env.GH_AW_CHECKOUT_MANIFEST = manifestPath;
+      resetCheckoutManifestCache();
+    });
+
+    afterEach(() => {
+      if (originalManifestEnv === undefined) {
+        delete process.env.GH_AW_CHECKOUT_MANIFEST;
+      } else {
+        process.env.GH_AW_CHECKOUT_MANIFEST = originalManifestEnv;
+      }
+      resetCheckoutManifestCache();
+      try {
+        fs.rmSync(workspaceDir, { recursive: true, force: true });
+      } catch {
+        // ignore
+      }
+    });
+
+    it("findRepoCheckout returns the manifest path even when remote.origin.url has been clobbered", () => {
+      // Reproduces the bug from #37545: the workflow checked out githubnext/gh-aw-side-repo
+      // at the workspace root, but a later "Configure Git credentials" step rewrote
+      // origin to point at githubnext/gh-aw-test. The manifest is the source of truth.
+      fs.writeFileSync(
+        manifestPath,
+        JSON.stringify({
+          "githubnext/gh-aw-side-repo": {
+            repository: "githubnext/gh-aw-side-repo",
+            path: "",
+            default_branch: "main",
+          },
+        })
+      );
+
+      const result = findRepoCheckout("githubnext/gh-aw-side-repo", workspaceDir);
+
+      expect(result.success).toBe(true);
+      expect(result.path).toBe(workspaceDir);
+      expect(result.repoSlug).toBe("githubnext/gh-aw-side-repo");
+    });
+
+    it("findRepoCheckout resolves manifest entries with a non-empty path to a subdirectory", () => {
+      fs.writeFileSync(
+        manifestPath,
+        JSON.stringify({
+          "owner/sub-repo": {
+            repository: "owner/sub-repo",
+            path: "repos/sub-repo",
+            default_branch: "main",
+          },
+        })
+      );
+
+      const result = findRepoCheckout("owner/sub-repo", workspaceDir);
+
+      expect(result.success).toBe(true);
+      expect(result.path).toBe(path.join(workspaceDir, "repos/sub-repo"));
+    });
+
+    it("findRepoCheckout is case-insensitive on the repo slug", () => {
+      fs.writeFileSync(
+        manifestPath,
+        JSON.stringify({
+          "githubnext/gh-aw-side-repo": {
+            repository: "githubnext/gh-aw-side-repo",
+            path: "",
+            default_branch: "main",
+          },
+        })
+      );
+
+      const result = findRepoCheckout("GithubNext/gh-aw-side-repo", workspaceDir);
+
+      expect(result.success).toBe(true);
+      expect(result.path).toBe(workspaceDir);
+    });
+
+    it("findRepoCheckout still applies allowedRepos validation when the manifest matches", () => {
+      fs.writeFileSync(
+        manifestPath,
+        JSON.stringify({
+          "owner/blocked": { repository: "owner/blocked", path: "blocked", default_branch: "main" },
+        })
+      );
+
+      const result = findRepoCheckout("owner/blocked", workspaceDir, {
+        allowedRepos: ["owner/allowed"],
+      });
+
+      expect(result.success).toBe(false);
+      expect(result.error).toBeDefined();
+    });
+
+    it("findRepoCheckout falls back to the git-remote scan when the manifest has no entry", () => {
+      fs.writeFileSync(manifestPath, JSON.stringify({}));
+
+      const result = findRepoCheckout("owner/missing", workspaceDir);
+
+      expect(result.success).toBe(false);
+      expect(result.error).toContain("not found in workspace");
+    });
+
+    it("buildRepoCheckoutMap seeds from manifest entries", () => {
+      fs.writeFileSync(
+        manifestPath,
+        JSON.stringify({
+          "githubnext/gh-aw-side-repo": {
+            repository: "githubnext/gh-aw-side-repo",
+            path: "",
+            default_branch: "main",
+          },
+          "owner/sub-repo": {
+            repository: "owner/sub-repo",
+            path: "repos/sub-repo",
+            default_branch: "main",
+          },
+        })
+      );
+
+      const map = buildRepoCheckoutMap(workspaceDir);
+
+      expect(map.get("githubnext/gh-aw-side-repo")).toBe(workspaceDir);
+      expect(map.get("owner/sub-repo")).toBe(path.join(workspaceDir, "repos/sub-repo"));
+    });
+  });
+
   describe("buildRepoCheckoutMap", () => {
     let testDir;