fix(land): wait for GitHub to show the fixer's push

src/cli/land-fixer.ts

@@ -82,6 +82,9 @@ async function comment(
 }
 
 /** Queue eligibility can eject a previously requeued PR before building another batch. */
+/** How many one-second pauses to wait for GitHub to show a pushed head. */
+const SYNC_PAUSES = 60;
+
 export async function handbackRepeated(
 	state: string,
 	plan: Plan,
@@ -402,7 +405,12 @@ async function collectJob(
 				}
 
 				if (result?.action === "fixed") {
-					const latest = object(await (await github.request(pullPath)).json());
+					// GitHub shows a push a moment later. Wait for our own head; only a third head is a real move.
+					let latest = object(await (await github.request(pullPath)).json());
+					for (let wait = 0; object(latest.head).sha === entry.head && wait < SYNC_PAUSES; wait++) {
+						await github.pause(1000);
+						latest = object(await (await github.request(pullPath)).json());
+					}
 					if (object(latest.head).sha !== head) throw new FixerRefusal("head moved before Review update");
 					await github.request(pullPath, {
 						method: "PATCH",

test/land.test.ts

@@ -1717,6 +1717,26 @@ describe("asynchronous land fixer", () => {
 		expect(fixture.pull.autoMerge?.commitBody).toBe(pin(fixture.pull.head!));
 		expect(fixture.pull.labels).toContain("quest:merge");
 	});
+	test("waits for GitHub to show the pushed fix before recording it", async () => {
+		const fixture = await fixerFixture(fixedScript(), { conflict: true });
+		await fixture.finished;
+		const deps = await fixture.forge.deps();
+		const old = fixture.plan.queue[0].head;
+		// GitHub's REST view lags the push: the first two reads after it still show the old head.
+		let stale = 2;
+		const original = deps.fetch;
+		deps.fetch = (async (input, init) => {
+			const response = await original(input, init);
+			if (!String(input).endsWith("/pulls/1") || (init?.method ?? "GET") !== "GET" || fixture.pull.head === old)
+				return response;
+			if (stale-- <= 0) return response;
+			const body = (await response.json()) as { head: Record<string, unknown> };
+			return Response.json({ ...body, head: { ...body.head, sha: old } });
+		}) as typeof fetch;
+		deps.sleep = async () => {};
+		expect(await fixture.collect(deps)).toEqual(["requeued 1"]);
+		expect(fixture.pull.body).toContain(`(head ${fixture.pull.head})`);
+	});
 	test.each([
 		[
 			"handback",