fix(orch): read live PR state when Graphite cache is stale

plugins/pstack/skills/poteto-mode/playbooks/orchestrate.md

@@ -77,7 +77,7 @@ A dependency is a context relay, not just ordering. Undeclared upstream context
 
 #### Stack safety
 
-- The frontier is a computed object, never narrative. Recompute `frontier.json` from `gt` after every merge and stack mutation because GitHub base refs drift mid-restack while gt tracking is authoritative: ordered PR list, branch names, head SHAs, a generation number, the lowest unmerged PR. Resolve it where gt knows the stack, normally the stacker's clone. A checkout whose gt metadata never saw the submits reports no PRs and the command errors rather than guessing.
+- The frontier is a computed object, never narrative. Recompute `frontier.json` after every merge and stack mutation because GitHub base refs drift mid-restack. `gt` supplies the authoritative stack order and branch mapping; `gh` supplies each PR's live open, merged, or closed state because `gt info` can return cached state while its background refresh is still running. Record the ordered PR list, branch names, head SHAs, a generation number, and the lowest unmerged PR. Resolve it from a branch in the target linear stack, normally in the stacker's clone. Do not resolve from a trunk with multiple tracked child stacks because `gt log --stack` returns a branching graph and `orch` refuses to guess a chain. A checkout whose gt metadata never saw the submits reports no PRs and the command errors rather than guessing.
 - Exactly one stacker per stack may run `gt`, serialized within its stack. Record the holder in the standing orders. A restack at this scale is slow and blocks whoever runs it, so give it its own unit and keep the coordinator out of it.
 - Workers never rebase and never run `gt`. Babysitters follow `playbooks/babysit.md`, one per stack, scoped to one immutable frontier generation. They report conflicts to the stacker rather than restacking.
 - PR closes and retargets go through the stacker only. Closing a base PR orphans every chain above it. Merges and stack surgery are units with briefs like any other.

plugins/pstack/skills/poteto-mode/scripts/orch/orch.test.ts

@@ -30,6 +30,12 @@ interface RunResult {
   readonly stderr: string;
 }
 
+interface FakeCliPaths {
+  readonly gh: string;
+  readonly gt: string;
+  readonly gtOutput: string;
+}
+
 async function makeDirectory(): Promise<string> {
   const directory = await mkdtemp(join(tmpdir(), "orch-test-"));
   directories.push(directory);
@@ -82,6 +88,15 @@ async function makeGitStack(directory: string): Promise<{
   git({ repo, args: ["init", "--initial-branch=main"] });
   git({ repo, args: ["config", "user.name", "Orch Test"] });
   git({ repo, args: ["config", "user.email", "orch@example.com"] });
+  git({
+    repo,
+    args: [
+      "remote",
+      "add",
+      "origin",
+      "https://github.com/contributor/widgets.git",
+    ],
+  });
   await writeFile(join(repo, "main.txt"), "main\n");
   git({ repo, args: ["add", "."] });
   git({ repo, args: ["commit", "-m", "main"] });
@@ -102,13 +117,13 @@ async function makeGitStack(directory: string): Promise<{
   };
 }
 
-async function withFakeGt<T>({
+async function withFakeGtAndGh<T>({
   directory,
   operation,
   output,
 }: {
   directory: string;
-  operation: (outputPath: string) => Promise<T>;
+  operation: (paths: FakeCliPaths) => Promise<T>;
   output: string;
 }): Promise<T> {
   const bin = join(directory, "bin");
@@ -129,13 +144,13 @@ case "$*" in
     cat "${outputPath}"
     ;;
   "--no-interactive info stack/merged")
-    printf 'stack/merged\\nPR #10 (Merged) merged change\\n'
+    printf 'stack/merged\\nPR #10 (New Graphite status) merged change\\nhttps://app.graphite.com/github/pr/base-owner/widgets/10\\ncommit body with an unrelated link\\nhttps://app.graphite.com/github/pr/other-owner/other-repo/99\\n'
     ;;
   "--no-interactive info stack/closed")
-    printf 'stack/closed\\nPR #13 (Closed) closed change\\n'
+    printf 'stack/closed\\nPR #13 (Closed) closed change\\nhttps://app.graphite.com/github/pr/base-owner/widgets/13\\n'
     ;;
   "--no-interactive info stack/open")
-    printf 'stack/open\\nPR #11 (Needs approvals) open change\\n'
+    printf 'stack/open\\nPR #11 (Needs approvals) open change\\nhttps://app.graphite.com/github/pr/base-owner/widgets/11\\n'
     ;;
   *)
     printf 'unexpected gt arguments: %s\\n' "$*" >&2
@@ -146,10 +161,34 @@ esac
   );
   await chmod(gt, 0o755);
 
+  const gh = join(bin, "gh");
+  await writeFile(
+    gh,
+    `#!/usr/bin/env bash
+set -euo pipefail
+case "$*" in
+  "pr view 10 --repo github.com/base-owner/widgets --json state --jq .state")
+    printf 'MERGED\\n'
+    ;;
+  "pr view 13 --repo github.com/base-owner/widgets --json state --jq .state")
+    printf 'CLOSED\\n'
+    ;;
+  "pr view 11 --repo github.com/base-owner/widgets --json state --jq .state")
+    printf 'OPEN\\n'
+    ;;
+  *)
+    printf 'unexpected gh arguments: %s\\n' "$*" >&2
+    exit 2
+    ;;
+esac
+`
+  );
+  await chmod(gh, 0o755);
+
   const originalPath = process.env.PATH;
   process.env.PATH = `${bin}:${originalPath ?? ""}`;
   try {
-    return await operation(outputPath);
+    return await operation({ gh, gt, gtOutput: outputPath });
   } finally {
     if (originalPath === undefined) {
       delete process.env.PATH;
@@ -406,7 +445,7 @@ describe("Store", () => {
     ]);
   });
 
-  it("resolves the ordered Graphite frontier and validates an optional pin", async () => {
+  it("uses adjacent PR metadata despite an unknown status and later PR link", async () => {
     const { directory, store } = await initializedStore();
     const stack = await makeGitStack(directory);
     const output = `◯ main
@@ -415,7 +454,7 @@ describe("Store", () => {
 ◉ stack/open (current)
 `;
 
-    await withFakeGt({
+    await withFakeGtAndGh({
       directory,
       output,
       operation: async () => {
@@ -478,11 +517,88 @@ describe("Store", () => {
     });
   });
 
+  it("preserves the previous frontier when GitHub state lookup fails", async () => {
+    const { directory, store } = await initializedStore();
+    const stack = await makeGitStack(directory);
+
+    await withFakeGtAndGh({
+      directory,
+      output: "◯ main\n◉ stack/merged\n",
+      operation: async ({ gh }) => {
+        const before = await store.frontier.set({ repo: stack.repo });
+        await writeFile(gh, "#!/usr/bin/env bash\nexit 1\n");
+
+        await expect(
+          store.frontier.set({ repo: stack.repo })
+        ).rejects.toThrow("gh pr view 10 failed for branch stack/merged");
+        expect(await store.frontier.show()).toEqual(before);
+      },
+    });
+  });
+
+  it("preserves the previous frontier when GitHub returns an invalid state", async () => {
+    const { directory, store } = await initializedStore();
+    const stack = await makeGitStack(directory);
+
+    await withFakeGtAndGh({
+      directory,
+      output: "◯ main\n◉ stack/merged\n",
+      operation: async ({ gh }) => {
+        const before = await store.frontier.set({ repo: stack.repo });
+        await writeFile(gh, "#!/usr/bin/env bash\nprintf 'UNKNOWN\\n'\n");
+
+        await expect(
+          store.frontier.set({ repo: stack.repo })
+        ).rejects.toThrow(
+          "gh pr view 10 returned an invalid state for branch stack/merged"
+        );
+        expect(await store.frontier.show()).toEqual(before);
+      },
+    });
+  });
+
+  it("preserves the previous frontier when Graphite PR identity mismatches", async () => {
+    const { directory, store } = await initializedStore();
+    const stack = await makeGitStack(directory);
+
+    await withFakeGtAndGh({
+      directory,
+      output: "◯ main\n◉ stack/merged\n",
+      operation: async ({ gt, gtOutput }) => {
+        const before = await store.frontier.set({ repo: stack.repo });
+        await writeFile(
+          gt,
+          `#!/usr/bin/env bash
+set -euo pipefail
+case "$*" in
+  "--no-interactive log short --stack --reverse")
+    cat "${gtOutput}"
+    ;;
+  "--no-interactive info stack/merged")
+    printf 'stack/merged\\nPR #10 (Ready to merge) change\\nhttps://app.graphite.com/github/pr/base-owner/widgets/12\\n'
+    ;;
+  *)
+    exit 2
+    ;;
+esac
+`
+        );
+
+        await expect(
+          store.frontier.set({ repo: stack.repo })
+        ).rejects.toThrow(
+          "gt info output PR identity mismatch for branch stack/merged: row 10, URL 12"
+        );
+        expect(await store.frontier.show()).toEqual(before);
+      },
+    });
+  });
+
   it("rejects unparseable Graphite output loudly", async () => {
     const { directory, store } = await initializedStore();
     const stack = await makeGitStack(directory);
 
-    await withFakeGt({
+    await withFakeGtAndGh({
       directory,
       output: "◯ main\nthis line is not Graphite output\n",
       operation: async () => {