test: probe for a free pid instead of assuming 4242 is dead

tests/cli-status-json.test.ts

@@ -7,6 +7,7 @@ import { tmpdir } from "node:os";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
 import { isConnectionRefused, isUncleanExitEvidence, proxyHealthFailureReason, resolveStatusPid, selectListenTarget } from "../src/cli/status";
+import { findDeadPid } from "./helpers/dead-pid";
 
 const repoRoot = dirname(fileURLToPath(new URL("../package.json", import.meta.url)));
 const cliPath = join(repoRoot, "src", "cli", "index.ts");
@@ -431,7 +432,7 @@ describe("unclean prior exit evidence", () => {
 describe("status reports stale process records end to end", () => {
   const seed = (home: string, opts: { pid?: number; runtime?: boolean; port: number }): void => {
     writeFileSync(join(home, "config.json"), JSON.stringify({ port: opts.port, codexAutoStart: false }), "utf8");
-    const pid = opts.pid ?? (process.pid === 4242 ? 4243 : 4242);
+    const pid = opts.pid ?? findDeadPid();
     if (opts.pid !== 0) writeFileSync(join(home, "ocx.pid"), String(pid), "utf8");
     if (opts.runtime) {
       writeFileSync(join(home, "runtime-port.json"), JSON.stringify({ pid, port: opts.port, hostname: "127.0.0.1" }), "utf8");
@@ -519,7 +520,7 @@ describe("status reports stale process records end to end", () => {
     await new Promise<void>(resolve => { occupied.listen(0, "127.0.0.1", () => resolve()); });
     const occupiedPort = (occupied.address() as AddressInfo).port;
     try {
-      const pid = process.pid === 4242 ? 4243 : 4242;
+      const pid = findDeadPid();
       writeFileSync(join(home, "config.json"), JSON.stringify({ port: occupiedPort, codexAutoStart: false }), "utf8");
       writeFileSync(join(home, "ocx.pid"), String(pid), "utf8");
       writeFileSync(join(home, "runtime-port.json"), JSON.stringify({ pid, port: freePort, hostname: "127.0.0.1" }), "utf8");

tests/doctor.test.ts

@@ -30,6 +30,7 @@ import {
   LOCAL_MANAGEMENT_READ_PATHS,
   verifyLocalManagementReadCapability,
 } from "../src/lib/local-management-capability";
+import { findDeadPid } from "./helpers/dead-pid";
 
 const TEST_DIR = join(import.meta.dir, ".tmp-doctor-test");
 const TEST_CODEX_HOME = join(TEST_DIR, "codex");
@@ -802,7 +803,7 @@ describe("doctor reclaim wiring (end to end)", () => {
   });
 
   const seedStaleTemp = (): string => {
-    const deadPid = process.pid === 4242 ? 4243 : 4242;
+    const deadPid = findDeadPid();
     const path = join(tempHome, `responses-state.json.ocx.${deadPid}.1.tmp`);
     writeFileSync(path, "abandoned snapshot");
     const old = new Date(Date.now() - 48 * 60 * 60 * 1_000);
@@ -867,7 +868,7 @@ describe("doctor reports an unclean prior proxy exit", () => {
   const deadPid = (): number => {
     const spawned = spawnSync(process.execPath, ["-e", ""], { encoding: "utf8" });
     const pid = spawned.pid;
-    return typeof pid === "number" && pid > 0 ? pid : (process.pid === 4242 ? 4243 : 4242);
+    return typeof pid === "number" && pid > 0 ? pid : findDeadPid();
   };
 
   // Port 9 is the discard port: nothing listens, so the health probe is refused rather

tests/helpers/dead-pid.ts

@@ -0,0 +1,32 @@
+/**
+ * A pid that is genuinely free, probed rather than assumed.
+ *
+ * Several suites need a pid that stands in for a process that has exited: stale
+ * `ocx.pid` records, abandoned response-state temps, doctor's reclaim paths. The
+ * code under test asks the kernel whether that owner is still alive, so a
+ * hardcoded "dead" pid is only dead until some unrelated process happens to hold
+ * it — and then the production code answers correctly, the test reads that as a
+ * miss, and the failure looks like a defect in the feature.
+ *
+ * That is not hypothetical. On the macOS host where this helper was written, pid
+ * 4242 was `liveactivitiesd`, and every suite that assumed it dead failed at once:
+ * `periodic reclaim frees abandoned temps`, both `doctor reclaim wiring` cases and
+ * both `status reports stale process records` cases. `tests/responses-state.test.ts`
+ * already probed for a free pid inline, with a comment naming this exact hazard;
+ * this helper is that probe, shared instead of copied.
+ *
+ * ESRCH is the only answer that proves absence. A successful `kill(pid, 0)` means
+ * the process is alive, and EPERM means it is alive but owned by somebody else —
+ * both disqualify the candidate.
+ */
+export function findDeadPid(): number {
+  for (let candidate = 4242; candidate < 5242; candidate += 1) {
+    if (candidate === process.pid) continue;
+    try {
+      process.kill(candidate, 0);
+    } catch (error) {
+      if ((error as NodeJS.ErrnoException).code === "ESRCH") return candidate;
+    }
+  }
+  throw new Error("no free pid in [4242, 5242) to stand in for a dead owner");
+}

tests/responses-state.test.ts

@@ -1,5 +1,6 @@
 import { afterEach, beforeEach, describe, expect, test } from "bun:test";
 import { BULK_DURABLE_IO_BUDGET_MS } from "./helpers/test-budget";
+import { findDeadPid } from "./helpers/dead-pid";
 import {
   closeSync,
   existsSync,
@@ -2176,7 +2177,7 @@ describe("Responses previous_response_id state", () => {
 
   test("recovers only old response-state temps owned by dead processes", () => {
     const old = new Date(Date.now() - 60 * 60 * 1_000);
-    const deadPid = process.pid === 4242 ? 4243 : 4242;
+    const deadPid = findDeadPid();
     const stale = join(home, `responses-state.json.ocx.${deadPid}.1.tmp`);
     const live = join(home, "responses-state.json.ocx.5252.2.tmp");
     const current = join(home, `responses-state.json.ocx.${process.pid}.3.tmp`);
@@ -2210,21 +2211,7 @@ describe("Responses previous_response_id state", () => {
     symlinkSync(realSnapshot, join(home, "responses-state.json"));
 
     // This test drives the REAL load path, whose sweep probes live pids with kill(pid, 0).
-    // A hardcoded "dead" pid can collide with a live process on a shared CI runner, so
-    // probe for a genuinely dead one instead (ESRCH). EPERM means alive-but-not-ours.
-    let deadPid = -1;
-    for (let candidate = 4242; candidate < 5242; candidate++) {
-      if (candidate === process.pid) continue;
-      try {
-        process.kill(candidate, 0);
-      } catch (error) {
-        if ((error as NodeJS.ErrnoException).code === "ESRCH") {
-          deadPid = candidate;
-          break;
-        }
-      }
-    }
-    expect(deadPid).toBeGreaterThan(0);
+    const deadPid = findDeadPid();
     const stranded = join(realDir, `responses-state.json.ocx.${deadPid}.1.tmp`);
     writeFileSync(stranded, "private state");
     const old = new Date(Date.now() - 60 * 60 * 1_000);
@@ -2238,7 +2225,7 @@ describe("Responses previous_response_id state", () => {
   });
 
   test("stale temp recovery is best-effort when unlink fails", () => {
-    const deadPid = process.pid === 4242 ? 4243 : 4242;
+    const deadPid = findDeadPid();
     const path = join(home, `responses-state.json.ocx.${deadPid}.1.tmp`);
     writeFileSync(path, "private state");
     const old = new Date(Date.now() - 60 * 60 * 1_000);
@@ -2303,7 +2290,7 @@ describe("Responses previous_response_id state", () => {
     // schedulePersist site sits downstream of, so a process had its only look BEFORE it
     // wrote anything. Here nothing touches the continuation store at all.
     const old = new Date(Date.now() - 60 * 60 * 1_000);
-    const deadPid = process.pid === 4242 ? 4243 : 4242;
+    const deadPid = findDeadPid();
     const stale = join(home, `responses-state.json.ocx.${deadPid}.1.tmp`);
     const young = join(home, "responses-state.json.ocx.6262.4.tmp");
     for (const path of [stale, young]) writeFileSync(path, "private state");
@@ -2401,7 +2388,7 @@ describe("Responses previous_response_id state", () => {
     // Report and reclaim must share one predicate. If they drift, doctor tells an operator
     // to reclaim files it will then refuse to touch (or vice versa).
     const old = new Date(Date.now() - 60 * 60 * 1_000);
-    const deadPid = process.pid === 4242 ? 4243 : 4242;
+    const deadPid = findDeadPid();
     const stale = join(home, `responses-state.json.ocx.${deadPid}.1.tmp`);
     const live = join(home, "responses-state.json.ocx.5252.2.tmp");
     const young = join(home, "responses-state.json.ocx.6262.3.tmp");