dedupe crash diagnostics and add tests

Author: charlesvien

apps/code/src/main/index.ts

@@ -30,7 +30,10 @@ import type { SuspensionService } from "./services/suspension/service";
 import type { TaskLinkService } from "./services/task-link/service";
 import type { UpdatesService } from "./services/updates/service";
 import type { WorkspaceService } from "./services/workspace/service";
-import { collectMemorySnapshot } from "./utils/crash-diagnostics";
+import {
+  collectMemorySnapshot,
+  flattenMemorySnapshot,
+} from "./utils/crash-diagnostics";
 import { ensureClaudeConfigDir } from "./utils/env";
 import {
   getChromiumLogFilePath,
@@ -72,9 +75,18 @@ function isCrashLoop(): boolean {
   return recentCrashTimestamps.length >= CRASH_LOOP_THRESHOLD;
 }
 
+// Shared diagnostics attached to every crash event: uptime, the native chromium
+// log tail, and flattened memory. A hard OOM kills the renderer before it can
+// log, so the memory snapshot is often the only signal of what happened.
+function crashDiagnostics() {
+  return {
+    appUptimeSeconds: Math.round(process.uptime()),
+    chromiumLogTail: readChromiumLogTail(),
+    ...flattenMemorySnapshot(collectMemorySnapshot(() => app.getAppMetrics())),
+  };
+}
+
 app.on("render-process-gone", (_event, webContents, details) => {
-  const memory = collectMemorySnapshot(() => app.getAppMetrics());
-  const chromiumLogTail = readChromiumLogTail();
   const props = {
     source: "main",
     type: "render-process-gone",
@@ -83,16 +95,11 @@ app.on("render-process-gone", (_event, webContents, details) => {
     url: webContents.getURL(),
     title: webContents.getTitle(),
     webContentsId: String(webContents.id),
-    appUptimeSeconds: Math.round(process.uptime()),
-    memoryTotalWorkingSetKb: memory?.totalWorkingSetKb,
-    memoryPeakWorkingSetKb: memory?.peakWorkingSetKb,
-    memoryProcessCount: memory?.processCount,
-    memoryByType: memory ? JSON.stringify(memory.byType) : undefined,
+    ...crashDiagnostics(),
   };
-  log.error("Renderer process gone", { ...props, chromiumLogTail });
+  log.error("Renderer process gone", props);
   captureException(new Error(`Renderer process gone: ${details.reason}`), {
     ...props,
-    chromiumLogTail,
     // Stack is always this handler, so default grouping collapses every
     // renderer death into one issue. Split by reason instead.
     $exception_fingerprint: ["render-process-gone", details.reason],
@@ -129,8 +136,6 @@ app.on("render-process-gone", (_event, webContents, details) => {
 });
 
 app.on("child-process-gone", (_event, details) => {
-  const memory = collectMemorySnapshot(() => app.getAppMetrics());
-  const chromiumLogTail = readChromiumLogTail();
   const props = {
     source: "main",
     type: "child-process-gone",
@@ -139,18 +144,13 @@ app.on("child-process-gone", (_event, details) => {
     exitCode: String(details.exitCode),
     serviceName: details.serviceName ?? "",
     name: details.name ?? "",
-    appUptimeSeconds: Math.round(process.uptime()),
-    memoryTotalWorkingSetKb: memory?.totalWorkingSetKb,
-    memoryPeakWorkingSetKb: memory?.peakWorkingSetKb,
-    memoryProcessCount: memory?.processCount,
-    memoryByType: memory ? JSON.stringify(memory.byType) : undefined,
+    ...crashDiagnostics(),
   };
-  log.error("Child process gone", { ...props, chromiumLogTail });
+  log.error("Child process gone", props);
   captureException(
     new Error(`Child process gone (${details.type}): ${details.reason}`),
     {
       ...props,
-      chromiumLogTail,
       $exception_fingerprint: [
         "child-process-gone",
         details.type,

apps/code/src/main/services/posthog-analytics.test.ts

@@ -10,6 +10,7 @@ vi.mock("posthog-node", () => ({ PostHog: MockPostHog }));
 
 import {
   captureException,
+  getOrCreateSessionId,
   initializePostHog,
   resetUser,
   shutdownPostHog,
@@ -101,8 +102,15 @@ describe("posthog-analytics", () => {
   it("stamps the main-owned session id and ignores a caller override", () => {
     captureException(new Error("boom"), { $session_id: "spoofed" });
 
-    const props = mockCaptureException.mock.calls.at(-1)?.[2];
-    expect(props.$session_id).toMatch(
+    const [, , props] = mockCaptureException.mock.calls.at(-1) ?? [];
+    expect(props.$session_id).toBe(getOrCreateSessionId());
+  });
+
+  it("mints a stable valid uuidv7 session id", () => {
+    const first = getOrCreateSessionId();
+
+    expect(getOrCreateSessionId()).toBe(first);
+    expect(first).toMatch(
       /^[0-9a-f]{8}-[0-9a-f]{4}-7[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/,
     );
   });

apps/code/src/main/services/posthog-analytics.ts

@@ -58,10 +58,6 @@ export function getOrCreateSessionId(): string {
   return sessionId;
 }
 
-export function getSessionId(): string | null {
-  return sessionId;
-}
-
 export function trackAppEvent(
   eventName: string,
   properties?: Record<string, string | number | boolean>,

apps/code/src/main/utils/crash-diagnostics.test.ts

@@ -1,5 +1,8 @@
 import { describe, expect, it } from "vitest";
-import { collectMemorySnapshot } from "./crash-diagnostics";
+import {
+  collectMemorySnapshot,
+  flattenMemorySnapshot,
+} from "./crash-diagnostics";
 
 function metric(
   type: string,
@@ -46,3 +49,25 @@ describe("collectMemorySnapshot", () => {
     ).toBeUndefined();
   });
 });
+
+describe("flattenMemorySnapshot", () => {
+  it("flattens scalars and serializes byType for PostHog", () => {
+    expect(
+      flattenMemorySnapshot({
+        totalWorkingSetKb: 430,
+        peakWorkingSetKb: 500,
+        processCount: 4,
+        byType: { Browser: 100, Tab: 250, GPU: 80 },
+      }),
+    ).toEqual({
+      memoryTotalWorkingSetKb: 430,
+      memoryPeakWorkingSetKb: 500,
+      memoryProcessCount: 4,
+      memoryByType: '{"Browser":100,"Tab":250,"GPU":80}',
+    });
+  });
+
+  it("returns an empty object when no snapshot was collected", () => {
+    expect(flattenMemorySnapshot(undefined)).toEqual({});
+  });
+});

apps/code/src/main/utils/crash-diagnostics.ts

@@ -47,3 +47,22 @@ export function collectMemorySnapshot(
     return undefined;
   }
 }
+
+/**
+ * Flatten a snapshot into scalar event properties for PostHog (which doesn't
+ * accept nested objects, so `byType` is serialized). Returns `{}` when no
+ * snapshot was collected, so it spreads cleanly into a crash event's props.
+ */
+export function flattenMemorySnapshot(
+  memory: MemorySnapshot | undefined,
+): Record<string, number | string> {
+  if (!memory) {
+    return {};
+  }
+  return {
+    memoryTotalWorkingSetKb: memory.totalWorkingSetKb,
+    memoryPeakWorkingSetKb: memory.peakWorkingSetKb,
+    memoryProcessCount: memory.processCount,
+    memoryByType: JSON.stringify(memory.byType),
+  };
+}

apps/code/src/main/utils/uuidv7.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 import { uuidv7 } from "./uuidv7";
 
 const UUID_V7 =
@@ -26,4 +26,16 @@ describe("uuidv7", () => {
     const ids = new Set(Array.from({ length: 1000 }, () => uuidv7()));
     expect(ids.size).toBe(1000);
   });
+
+  it("writes the 48-bit millisecond timestamp big-endian into the first 6 bytes", () => {
+    vi.spyOn(Date, "now").mockReturnValue(0x0123456789ab);
+    try {
+      const id = uuidv7();
+      // bytes 0-5 of 0x0123456789ab -> "01234567" then "89ab"
+      expect(id.slice(0, 8)).toBe("01234567");
+      expect(id.slice(9, 13)).toBe("89ab");
+    } finally {
+      vi.restoreAllMocks();
+    }
+  });
 });

apps/code/src/renderer/utils/analytics.test.ts

@@ -148,4 +148,29 @@ describe("initializePostHog", () => {
     expect(mockPosthog.init).not.toHaveBeenCalled();
     expect(mockPosthog.onFeatureFlags).not.toHaveBeenCalled();
   });
+
+  it("bootstraps posthog with the main-owned session id", async () => {
+    const { initializePostHog } = await loadAnalytics();
+
+    initializePostHog("0190abcd-1234-7890-8abc-def012345678");
+
+    expect(mockPosthog.init).toHaveBeenCalledWith(
+      "test-key",
+      expect.objectContaining({
+        bootstrap: { sessionID: "0190abcd-1234-7890-8abc-def012345678" },
+        session_idle_timeout_seconds: 36_000,
+      }),
+    );
+  });
+
+  it("omits bootstrap when no session id is provided", async () => {
+    const { initializePostHog } = await loadAnalytics();
+
+    initializePostHog();
+
+    expect(mockPosthog.init).toHaveBeenCalledWith(
+      "test-key",
+      expect.not.objectContaining({ bootstrap: expect.anything() }),
+    );
+  });
 });

apps/code/src/renderer/utils/analytics.ts

@@ -36,6 +36,11 @@ type PendingFlagListener = {
 // Subscribers added before initializePostHog runs.
 const pendingFlagListeners = new Set<PendingFlagListener>();
 
+// 10 h, the posthog-js maximum. The app sits idle for hours during background
+// tasks; a shorter timeout would rotate the session id and break the
+// main-owned crash->replay link.
+const SESSION_IDLE_TIMEOUT_SECONDS = 36_000;
+
 /**
  * @param sessionId Main-owned session id (UUIDv7) to bootstrap posthog-js with,
  *   so the recording shares the id main stamps on crash events. Main owns it so
@@ -56,11 +61,9 @@ export function initializePostHog(sessionId?: string) {
     api_host: apiHost,
     ui_host: uiHost,
     disable_session_recording: false,
-    // Hold the session open through long idle (max posthog-js allows) so its
-    // own rotation doesn't replace main's bootstrapped id mid-run. This app
-    // sits idle for hours with background tasks, which is exactly when a
-    // shorter timeout would silently rotate and break crash->replay linking.
-    session_idle_timeout_seconds: 36000,
+    // Hold the session open through long idle so posthog-js's own rotation
+    // doesn't replace main's bootstrapped id mid-run.
+    session_idle_timeout_seconds: SESSION_IDLE_TIMEOUT_SECONDS,
     ...(sessionId ? { bootstrap: { sessionID: sessionId } } : {}),
     capture_exceptions: import.meta.env.DEV
       ? false