fix(server): measure degraded watchers through physical temp paths

Git canonicalizes the checkout root. Match that spelling in the benchmark fixture so a symlinked temporary directory still triggers the simulated watcher failure and degraded polling.

packages/server/scripts/measure-git-observation.ts

@@ -1,5 +1,5 @@
 import { execFileSync } from "node:child_process";
-import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { mkdirSync, mkdtempSync, realpathSync, rmSync, writeFileSync } from "node:fs";
 import { writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import path from "node:path";
@@ -12,6 +12,7 @@ import {
 import {
   startGitCommandMetrics,
   stopGitCommandMetrics,
+  waitForGitCommandMetricsIdle,
   type GitCommandMetricsSnapshot,
 } from "../src/utils/run-git-command.js";
 import { CheckoutDiffManager } from "../src/server/checkout-diff-manager.js";
@@ -160,6 +161,7 @@ async function measurePhase(input: {
         serviceMetrics.workspaceRefreshQueuedCount === 0
       );
     }, "observation queue to drain");
+    await waitForGitCommandMetricsIdle({ quietMs: 1_500, timeoutMs: 8_000 });
   } finally {
     metrics = stopGitCommandMetrics();
   }
@@ -189,7 +191,11 @@ async function closeMeasuredService(input: {
 }
 
 async function main(): Promise<void> {
-  const tempDir = mkdtempSync(path.join(tmpdir(), "paseo-git-observation-measurement-"));
+  // Git reports physical roots; keep watcher-failure injection in that same
+  // spelling when the system temporary directory is a symlink.
+  const tempDir = realpathSync(
+    mkdtempSync(path.join(tmpdir(), "paseo-git-observation-measurement-")),
+  );
   const repoDir = path.join(tempDir, "repo");
   const paseoHome = path.join(tempDir, "paseo-home");
   const trackedPath = path.join(repoDir, "tracked.txt");
@@ -243,7 +249,9 @@ async function main(): Promise<void> {
         healthy.watcher.subscriptions.size === 2,
       "healthy bootstrap",
     );
-    await sleep(250);
+    // Linux startup discovery schedules a one-second debounced refresh even
+    // after subscriptions are ready. Keep that work in the bootstrap phase.
+    await waitForGitCommandMetricsIdle({ quietMs: 1_500, timeoutMs: 8_000 });
     const bootstrapMetrics = stopGitCommandMetrics();
     const bootstrapServiceMetrics = healthy.service.getMetrics();
     phases.bootstrap = {
@@ -342,6 +350,7 @@ async function main(): Promise<void> {
     diffManager = null;
     await closeMeasuredService({
       service: healthy.service,
+      observer: healthy.watcher.observer,
       subscriptions: healthy.watcher.subscriptions,
     });
     healthy = null;
@@ -357,7 +366,9 @@ async function main(): Promise<void> {
         degraded.service.getMetrics().workspaceObservationSetupInFlightCount === 0,
       "degraded bootstrap",
     );
-    await sleep(250);
+    // Linux startup discovery schedules a one-second debounced refresh even
+    // after subscriptions are ready. Keep that work in the bootstrap phase.
+    await waitForGitCommandMetricsIdle({ quietMs: 1_500, timeoutMs: 8_000 });
     const degradedBootstrapMetrics = stopGitCommandMetrics();
     const degradedBootstrapServiceMetrics = degraded.service.getMetrics();
     phases.degradedBootstrap = {

packages/server/src/server/workspace-git-service.observation.integration.test.ts

@@ -1,5 +1,15 @@
-import { mkdirSync, mkdtempSync, readFileSync, realpathSync, rmSync, writeFileSync } from "node:fs";
-import { execFileSync } from "node:child_process";
+import {
+  mkdirSync,
+  mkdtempSync,
+  readFileSync,
+  realpathSync,
+  rmSync,
+  symlinkSync,
+  writeFileSync,
+} from "node:fs";
+import { execFile, execFileSync } from "node:child_process";
+import { promisify } from "node:util";
+import { fileURLToPath } from "node:url";
 import { tmpdir } from "node:os";
 import path from "node:path";
 import pino from "pino";
@@ -522,3 +532,44 @@ test("a late Git-ignored tree is pruned while tracked changes still notify consu
     rmSync(tempDir, { recursive: true, force: true });
   }
 }, 15_000);
+
+test("Git observation measurement separates startup from idle and reaches its degraded summary", async () => {
+  const script = fileURLToPath(
+    new URL("../../scripts/measure-git-observation.ts", import.meta.url),
+  );
+  const root = realpathSync(mkdtempSync(path.join(tmpdir(), "paseo-measurement-test-")));
+  const actualTemp = path.join(root, "actual");
+  const aliasedTemp = path.join(root, "alias");
+  mkdirSync(actualTemp);
+  symlinkSync(actualTemp, aliasedTemp, "junction");
+  cleanup.push(async () => rmSync(root, { recursive: true, force: true }));
+  const { stdout } = await promisify(execFile)(process.execPath, ["--import", "tsx", script], {
+    env: { ...process.env, TMPDIR: aliasedTemp, TMP: aliasedTemp, TEMP: aliasedTemp },
+    timeout: 30_000,
+    maxBuffer: 1024 * 1024,
+  });
+  const summary = stdout
+    .split("\n")
+    .find((line) => line.startsWith("GIT_OBSERVATION_MEASUREMENT "));
+  expect(summary).toBeTypeOf("string");
+  const report = JSON.parse(summary!.slice("GIT_OBSERVATION_MEASUREMENT ".length));
+  expect(Object.keys(report.phases)).toEqual([
+    "bootstrap",
+    "legacyFullRefreshReference",
+    "idle",
+    "activeDiff",
+    "editBurst",
+    "ignoredStorm",
+    "degradedBootstrap",
+    "degradedWatcher",
+  ]);
+  expect(report.phases.idle.gitCommands).toBe(0);
+  expect(report.phases.ignoredStorm.gitCommands).toBe(0);
+  expect(report.phases.bootstrap.producers.structural).toBeGreaterThanOrEqual(1);
+  expect(report.phases.activeDiff.producers.worktree).toBeGreaterThanOrEqual(1);
+  expect(report.phases.editBurst.producers.worktree).toBeLessThanOrEqual(2);
+  expect(report.phases.degradedWatcher.producers.worktree).toBeGreaterThanOrEqual(1);
+  for (const phase of Object.values(report.phases) as Array<{ queueAfter: unknown }>) {
+    expect(phase.queueAfter).toEqual({ inFlight: 0, queued: 0 });
+  }
+}, 35_000);