fix: Linux checkout diff watchers using non-recursive directory watching

Use non-recursive directory watchers on Linux since recursive fs.watch
is not supported. Dynamically discover and watch subdirectories, refreshing
the watcher tree on changes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/server/src/server/checkout-diff-manager.test.ts

@@ -0,0 +1,153 @@
+commit 07b077f1a28e7126f9d2b48be03bca8486173aac
+Author: Mohamed Boudra <boudra.moha@gmail.com>
+Date:   Wed Apr 1 04:38:45 2026 +0000
+
+    fix: Linux checkout diff watchers and rewind command ordering
+    
+    Use non-recursive directory watchers on Linux since recursive fs.watch
+    is not supported. Dynamically discover and watch subdirectories, refreshing
+    the watcher tree on changes. Also pin rewind command first in the slash
+    command list and remove stale .gitignore entry.
+    
+    Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+
+diff --git a/packages/server/src/server/checkout-diff-manager.test.ts b/packages/server/src/server/checkout-diff-manager.test.ts
+new file mode 100644
+index 00000000..22f0fda8
+--- /dev/null
++++ b/packages/server/src/server/checkout-diff-manager.test.ts
+@@ -0,0 +1,134 @@
++import path from "node:path";
++import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
++
++const { execMock, getCheckoutDiffMock, resolveCheckoutGitDirMock, readdirMock, watchCalls } =
++  vi.hoisted(() => {
++    const hoistedWatchCalls: Array<{ path: string; close: ReturnType<typeof vi.fn> }> = [];
++    return {
++      execMock: vi.fn((_command: string, _options: unknown, callback: (error: null, result: { stdout: string; stderr: string }) => void) => {
++        callback(null, { stdout: "/tmp/repo\n", stderr: "" });
++      }),
++      getCheckoutDiffMock: vi.fn(async () => ({ diff: "", structured: [] })),
++      resolveCheckoutGitDirMock: vi.fn(async () => "/tmp/repo/.git"),
++      readdirMock: vi.fn(async (directory: string) => {
++        if (directory === "/tmp/repo") {
++          return [
++            { name: "packages", isDirectory: () => true },
++            { name: ".git", isDirectory: () => true },
++            { name: "README.md", isDirectory: () => false },
++          ];
++        }
++        if (directory === path.join("/tmp/repo", "packages")) {
++          return [
++            { name: "server", isDirectory: () => true },
++            { name: "app", isDirectory: () => true },
++          ];
++        }
++        if (directory === path.join("/tmp/repo", "packages", "server")) {
++          return [{ name: "src", isDirectory: () => true }];
++        }
++        if (directory === path.join("/tmp/repo", "packages", "server", "src")) {
++          return [{ name: "server", isDirectory: () => true }];
++        }
++        return [];
++      }),
++      watchCalls: hoistedWatchCalls,
++    };
++  });
++
++vi.mock("child_process", () => ({
++  exec: execMock,
++}));
++
++vi.mock("node:fs/promises", async () => {
++  const actual = await vi.importActual<typeof import("node:fs/promises")>("node:fs/promises");
++  return {
++    ...actual,
++    readdir: readdirMock,
++  };
++});
++
++vi.mock("node:fs", async () => {
++  const actual = await vi.importActual<typeof import("node:fs")>("node:fs");
++  return {
++    ...actual,
++    watch: vi.fn((watchPath: string) => {
++      const close = vi.fn();
++      watchCalls.push({ path: watchPath, close });
++      return {
++        close,
++        on: vi.fn().mockReturnThis(),
++      } as any;
++    }),
++  };
++});
++
++vi.mock("../utils/checkout-git.js", () => ({
++  getCheckoutDiff: getCheckoutDiffMock,
++}));
++
++vi.mock("./checkout-git-utils.js", () => ({
++  READ_ONLY_GIT_ENV: {},
++  resolveCheckoutGitDir: resolveCheckoutGitDirMock,
++  toCheckoutError: vi.fn((error: unknown) => ({
++    message: error instanceof Error ? error.message : String(error),
++  })),
++}));
++
++import { CheckoutDiffManager } from "./checkout-diff-manager.js";
++
++describe("CheckoutDiffManager Linux watchers", () => {
++  const originalPlatform = process.platform;
++
++  beforeEach(() => {
++    watchCalls.length = 0;
++    execMock.mockClear();
++    getCheckoutDiffMock.mockClear();
++    resolveCheckoutGitDirMock.mockClear();
++    readdirMock.mockClear();
++    Object.defineProperty(process, "platform", {
++      configurable: true,
++      value: "linux",
++    });
++  });
++
++  afterEach(() => {
++    Object.defineProperty(process, "platform", {
++      configurable: true,
++      value: originalPlatform,
++    });
++  });
++
++  test("watches nested repository directories on Linux", async () => {
++    const logger = {
++      child: () => logger,
++      warn: vi.fn(),
++    };
++    const manager = new CheckoutDiffManager({
++      logger: logger as any,
++      paseoHome: "/tmp/paseo-test",
++    });
++
++    const subscription = await manager.subscribe(
++      {
++        cwd: path.join("/tmp/repo", "packages", "server"),
++        compare: { mode: "uncommitted" },
++      },
++      () => {},
++    );
++
++    expect(subscription.initial.error).toBeNull();
++    expect(watchCalls.map((entry) => entry.path).sort()).toEqual([
++      "/tmp/repo",
++      "/tmp/repo/.git",
++      "/tmp/repo/packages",
++      "/tmp/repo/packages/app",
++      "/tmp/repo/packages/server",
++      "/tmp/repo/packages/server/src",
++      "/tmp/repo/packages/server/src/server",
++    ]);
++
++    subscription.unsubscribe();
++    manager.dispose();
++  });
++});

packages/server/src/server/checkout-diff-manager.ts

@@ -1,4 +1,6 @@
 import { watch, type FSWatcher } from "node:fs";
+import { readdir } from "node:fs/promises";
+import { join } from "node:path";
 import { exec } from "child_process";
 import { promisify } from "util";
 import type pino from "pino";
@@ -39,6 +41,10 @@ type CheckoutDiffWatchTarget = {
   refreshQueued: boolean;
   latestPayload: CheckoutDiffSnapshotPayload | null;
   latestFingerprint: string | null;
+  watchedPaths: Set<string>;
+  repoWatchPath: string | null;
+  linuxTreeRefreshPromise: Promise<void> | null;
+  linuxTreeRefreshQueued: boolean;
 };
 
 export class CheckoutDiffManager {
@@ -145,6 +151,7 @@ export class CheckoutDiffManager {
       watcher.close();
     }
     target.watchers = [];
+    target.watchedPaths.clear();
     target.listeners.clear();
   }
 
@@ -276,9 +283,14 @@ export class CheckoutDiffManager {
       refreshQueued: false,
       latestPayload: null,
       latestFingerprint: null,
+      watchedPaths: new Set<string>(),
+      repoWatchPath: null,
+      linuxTreeRefreshPromise: null,
+      linuxTreeRefreshQueued: false,
     };
 
     const repoWatchPath = watchRoot ?? cwd;
+    target.repoWatchPath = repoWatchPath;
     const watchPaths = new Set<string>([repoWatchPath]);
     const gitDir = await resolveCheckoutGitDir(cwd);
     if (gitDir) {
@@ -287,52 +299,15 @@ export class CheckoutDiffManager {
 
     let hasRecursiveRepoCoverage = false;
     const allowRecursiveRepoWatch = process.platform !== "linux";
+    if (process.platform === "linux") {
+      hasRecursiveRepoCoverage = await this.ensureLinuxRepoTreeWatchers(target, repoWatchPath);
+    }
     for (const watchPath of watchPaths) {
-      const shouldTryRecursive = watchPath === repoWatchPath && allowRecursiveRepoWatch;
-      const createWatcher = (recursive: boolean): FSWatcher =>
-        watch(watchPath, { recursive }, () => {
-          this.scheduleTargetRefresh(target);
-        });
-
-      let watcher: FSWatcher | null = null;
-      let watcherIsRecursive = false;
-      try {
-        if (shouldTryRecursive) {
-          watcher = createWatcher(true);
-          watcherIsRecursive = true;
-        } else {
-          watcher = createWatcher(false);
-        }
-      } catch (error) {
-        if (shouldTryRecursive) {
-          try {
-            watcher = createWatcher(false);
-            this.logger.warn(
-              { err: error, watchPath, cwd, compare },
-              "Checkout diff recursive watch unavailable; using non-recursive fallback",
-            );
-          } catch (fallbackError) {
-            this.logger.warn(
-              { err: fallbackError, watchPath, cwd, compare },
-              "Failed to start checkout diff watcher",
-            );
-          }
-        } else {
-          this.logger.warn(
-            { err: error, watchPath, cwd, compare },
-            "Failed to start checkout diff watcher",
-          );
-        }
-      }
-
-      if (!watcher) {
+      if (process.platform === "linux" && watchPath === repoWatchPath) {
         continue;
       }
-
-      watcher.on("error", (error) => {
-        this.logger.warn({ err: error, watchPath, cwd, compare }, "Checkout diff watcher error");
-      });
-      target.watchers.push(watcher);
+      const shouldTryRecursive = watchPath === repoWatchPath && allowRecursiveRepoWatch;
+      const watcherIsRecursive = this.addWatcher(target, watchPath, shouldTryRecursive);
       if (watchPath === repoWatchPath && watcherIsRecursive) {
         hasRecursiveRepoCoverage = true;
       }
@@ -358,4 +333,148 @@ export class CheckoutDiffManager {
     this.targets.set(targetKey, target);
     return target;
   }
+
+  private addWatcher(
+    target: CheckoutDiffWatchTarget,
+    watchPath: string,
+    shouldTryRecursive: boolean,
+  ): boolean {
+    if (target.watchedPaths.has(watchPath)) {
+      return false;
+    }
+
+    const { cwd, compare } = target;
+    const onChange = () => {
+      if (process.platform === "linux" && target.repoWatchPath) {
+        void this.refreshLinuxRepoTreeWatchers(target);
+      }
+      this.scheduleTargetRefresh(target);
+    };
+    const createWatcher = (recursive: boolean): FSWatcher =>
+      watch(watchPath, { recursive }, () => {
+        onChange();
+      });
+
+    let watcher: FSWatcher | null = null;
+    let watcherIsRecursive = false;
+    try {
+      if (shouldTryRecursive) {
+        watcher = createWatcher(true);
+        watcherIsRecursive = true;
+      } else {
+        watcher = createWatcher(false);
+      }
+    } catch (error) {
+      if (shouldTryRecursive) {
+        try {
+          watcher = createWatcher(false);
+          this.logger.warn(
+            { err: error, watchPath, cwd, compare },
+            "Checkout diff recursive watch unavailable; using non-recursive fallback",
+          );
+        } catch (fallbackError) {
+          this.logger.warn(
+            { err: fallbackError, watchPath, cwd, compare },
+            "Failed to start checkout diff watcher",
+          );
+        }
+      } else {
+        this.logger.warn(
+          { err: error, watchPath, cwd, compare },
+          "Failed to start checkout diff watcher",
+        );
+      }
+    }
+
+    if (!watcher) {
+      return false;
+    }
+
+    watcher.on("error", (error) => {
+      this.logger.warn({ err: error, watchPath, cwd, compare }, "Checkout diff watcher error");
+    });
+    target.watchers.push(watcher);
+    target.watchedPaths.add(watchPath);
+    return watcherIsRecursive;
+  }
+
+  private async ensureLinuxRepoTreeWatchers(
+    target: CheckoutDiffWatchTarget,
+    rootPath: string,
+  ): Promise<boolean> {
+    const directories = await this.listLinuxWatchDirectories(rootPath);
+    let complete = true;
+    for (const directory of directories) {
+      const watcherWasRecursive = this.addWatcher(target, directory, false);
+      if (!watcherWasRecursive && !target.watchedPaths.has(directory)) {
+        complete = false;
+      }
+    }
+    return complete && target.watchedPaths.has(rootPath);
+  }
+
+  private async refreshLinuxRepoTreeWatchers(target: CheckoutDiffWatchTarget): Promise<void> {
+    if (process.platform !== "linux" || !target.repoWatchPath) {
+      return;
+    }
+    const rootPath = target.repoWatchPath;
+    if (target.linuxTreeRefreshPromise) {
+      target.linuxTreeRefreshQueued = true;
+      return;
+    }
+
+    target.linuxTreeRefreshPromise = (async () => {
+      do {
+        target.linuxTreeRefreshQueued = false;
+        try {
+          await this.ensureLinuxRepoTreeWatchers(target, rootPath);
+        } catch (error) {
+          this.logger.warn(
+            {
+              err: error,
+              cwd: target.cwd,
+              compare: target.compare,
+              rootPath,
+            },
+            "Failed to refresh Linux checkout diff tree watchers",
+          );
+        }
+      } while (target.linuxTreeRefreshQueued);
+    })();
+
+    try {
+      await target.linuxTreeRefreshPromise;
+    } finally {
+      target.linuxTreeRefreshPromise = null;
+    }
+  }
+
+  private async listLinuxWatchDirectories(rootPath: string): Promise<string[]> {
+    const directories: string[] = [];
+    const pending = [rootPath];
+
+    while (pending.length > 0) {
+      const directory = pending.pop();
+      if (!directory) {
+        continue;
+      }
+      directories.push(directory);
+
+      let entries;
+      try {
+        entries = await readdir(directory, { withFileTypes: true });
+      } catch {
+        continue;
+      }
+
+      for (const entry of entries) {
+        if (!entry.isDirectory() || entry.name === ".git") {
+          continue;
+        }
+        pending.push(join(directory, entry.name));
+      }
+    }
+
+    return directories;
+  }
 }