fix(studio): catch up the preview after missed file changes

packages/cli/src/server/fileWatcher.fs.test.ts

@@ -14,11 +14,10 @@ describe("createProjectWatcher on a real directory", () => {
     rmSync(dir, { recursive: true, force: true });
   });
 
-  const watchProject = async () => {
+  const watchProject = (projectDir = dir) => {
     const seen: string[] = [];
-    watcher = createProjectWatcher(dir);
+    watcher = createProjectWatcher(projectDir);
     watcher.addListener((path) => seen.push(path));
-    await new Promise((resolve) => setTimeout(resolve, 100));
     return seen;
   };
   const expectReported = async (seen: string[], path: string) => {
@@ -35,7 +34,7 @@ describe("createProjectWatcher on a real directory", () => {
     mkdirSync(join(dir, "compositions"));
     writeFileSync(join(dir, "index.html"), "v0");
     writeFileSync(join(dir, "compositions", "scene.html"), "v0");
-    const seen = await watchProject();
+    const seen = watchProject();
 
     for (const path of ["index.html", join("compositions", "scene.html")]) {
       replaceByRename(join(dir, path), "stamped");
@@ -47,10 +46,71 @@ describe("createProjectWatcher on a real directory", () => {
     }
   });
 
+  it.runIf(process.platform === "linux")(
+    "follows a project folder replaced by rename",
+    async () => {
+      dir = mkdtempSync(join(tmpdir(), "hf-watch-root-"));
+      const project = join(dir, "project");
+      const replacement = join(dir, "replacement");
+      mkdirSync(project);
+      mkdirSync(join(replacement, "scenes"), { recursive: true });
+      writeFileSync(join(project, "index.html"), "before");
+      writeFileSync(join(replacement, "index.html"), "after");
+      writeFileSync(join(replacement, "scenes", "intro.html"), "new scene");
+      const seen = watchProject(project);
+
+      renameSync(project, join(dir, "previous"));
+      renameSync(replacement, project);
+      await expectReported(seen, ".");
+      writeFileSync(join(project, "index.html"), "edited root");
+      await expectReported(seen, "index.html");
+      writeFileSync(join(project, "scenes", "intro.html"), "edited scene");
+      await expectReported(seen, join("scenes", "intro.html"));
+    },
+  );
+
+  it.runIf(process.platform === "linux")(
+    "re-arms after the project path is absent between replacements",
+    async () => {
+      dir = mkdtempSync(join(tmpdir(), "hf-watch-gap-"));
+      const project = join(dir, "project");
+      mkdirSync(project);
+      writeFileSync(join(project, "index.html"), "before");
+      const seen = watchProject(project);
+
+      renameSync(project, join(dir, "previous"));
+      await expectReported(seen, ".");
+      mkdirSync(project);
+      writeFileSync(join(project, "index.html"), "after");
+      await expectReported(seen, ".");
+      writeFileSync(join(project, "index.html"), "later edit");
+      await expectReported(seen, "index.html");
+    },
+  );
+
+  it.runIf(process.platform === "linux")(
+    "follows a replaced subdirectory's new inode",
+    async () => {
+      dir = mkdtempSync(join(tmpdir(), "hf-watch-subdir-"));
+      const scenes = join(dir, "scenes");
+      mkdirSync(scenes);
+      mkdirSync(join(dir, "replacement"));
+      writeFileSync(join(scenes, "intro.html"), "before");
+      writeFileSync(join(dir, "replacement", "intro.html"), "after");
+      const seen = watchProject();
+
+      renameSync(scenes, join(dir, "previous"));
+      renameSync(join(dir, "replacement"), scenes);
+      await expectReported(seen, "scenes");
+      writeFileSync(join(scenes, "intro.html"), "later edit");
+      await expectReported(seen, join("scenes", "intro.html"));
+    },
+  );
+
   it("reports Studio's manifest writes inside .hyperframes", async () => {
     dir = mkdtempSync(join(tmpdir(), "hf-watch-"));
     mkdirSync(join(dir, ".hyperframes"));
-    const seen = await watchProject();
+    const seen = watchProject();
 
     writeFileSync(join(dir, ".hyperframes", "studio-motion.json"), "{}");
     await expectReported(seen, join(".hyperframes", "studio-motion.json"));
@@ -60,7 +120,7 @@ describe("createProjectWatcher on a real directory", () => {
     dir = mkdtempSync(join(tmpdir(), "hf-watch-"));
     mkdirSync(join(dir, "scene"));
     mkdirSync(join(dir, "scenes"));
-    const seen = await watchProject();
+    const seen = watchProject();
 
     rmSync(join(dir, "scene"), { recursive: true });
     await expectReported(seen, "scene");
@@ -70,7 +130,7 @@ describe("createProjectWatcher on a real directory", () => {
 
   it("reports files in a directory created after it started", async () => {
     dir = mkdtempSync(join(tmpdir(), "hf-watch-"));
-    const seen = await watchProject();
+    const seen = watchProject();
 
     mkdirSync(join(dir, "scenes"));
     await expectReported(seen, "scenes");

packages/cli/src/server/fileWatcher.test.ts

@@ -97,6 +97,29 @@ describe("createProjectWatcher", () => {
     },
   );
 
+  it.runIf(process.platform === "linux")("closes every watch it opened, its parent's too", () => {
+    const projectWatcher = createProjectWatcher("/fake/project/dir");
+    const opened = vi.mocked(watch).mock.calls.map(([path]) => path);
+    expect(opened).toContain("/fake/project");
+    projectWatcher.close();
+    expect(mockWatcher.close).toHaveBeenCalledTimes(opened.length);
+  });
+
+  it.runIf(process.platform === "linux")(
+    "keeps reporting project files when its parent cannot be watched",
+    () => {
+      vi.useFakeTimers();
+      fakeDirs.unwatchable = "/fake/project";
+      const projectWatcher = createProjectWatcher("/fake/project/dir");
+      const listener = vi.fn();
+      projectWatcher.addListener(listener);
+      mockWatcher.emit("change", "change", "index.html");
+      vi.advanceTimersByTime(30);
+      expect(listener).toHaveBeenCalledExactlyOnceWith("index.html");
+      projectWatcher.close();
+    },
+  );
+
   it("degrades to no live reload when the project root cannot be watched", () => {
     fakeDirs.unwatchable = "/fake/project/dir";
     let projectWatcher: ReturnType<typeof createProjectWatcher> | null = null;

packages/cli/src/server/fileWatcher.ts

@@ -1,7 +1,10 @@
-import { lstatSync, readdirSync, watch, type FSWatcher } from "node:fs";
-import { join, relative, sep } from "node:path";
+import { lstatSync, readdirSync, watch, type Dirent, type FSWatcher } from "node:fs";
+import { basename, dirname, join, relative, sep } from "node:path";
 import { isAtomicTempPath } from "@hyperframes/core/atomic-file";
-import { affectsProjectSignature } from "@hyperframes/studio-server";
+import {
+  affectsProjectSignature,
+  STUDIO_SIGNATURE_MANIFEST_PATHS,
+} from "@hyperframes/studio-server";
 
 export type FileChangeListener = (relativePath: string) => void;
 
@@ -70,43 +73,63 @@ function watchProjectTree(
       }
     }
   };
-  const watchDirectory = (dir: string) => {
-    if (directories.has(dir)) return;
+  const watchDirectory = (dir: string, movedIn = false) => {
+    if (directories.has(dir)) unwatch(dir);
     let watcher: FSWatcher;
     try {
       watcher = watch(dir, { persistent: true }, (event, name) => {
         if (!name) return;
         const path = join(dir, name.toString());
         onChange(relative(projectDir, path));
         if (event !== "rename") return;
-        if (isDirectory(path)) descend(path);
+        if (isDirectory(path)) descend(path, true);
         else unwatch(path);
       });
-    } catch (error) {
-      // One unwatchable subdirectory (EACCES, inotify limit) must not cost the rest of the tree.
-      if (dir === projectDir) throw error;
+    } catch {
+      // A directory can vanish during replacement; its parent reports its return.
       return;
     }
     watcher.on("error", () => unwatch(dir));
     directories.set(dir, watcher);
-    let entries: string[] = [];
+    walkChildren(dir, movedIn);
+  };
+  const walkChildren = (dir: string, movedIn: boolean) => {
+    let entries: Dirent[] = [];
     try {
-      entries = readdirSync(dir, { withFileTypes: true })
-        .filter((entry) => entry.isDirectory())
-        .map((entry) => join(dir, entry.name));
+      entries = readdirSync(dir, { withFileTypes: true });
     } catch {
       // Gone before we could list it; its parent reports the removal.
     }
-    for (const child of entries) descend(child);
+    for (const entry of entries) {
+      const child = join(dir, entry.name);
+      // A folder moved in brings files that never get an event of their own, and drops others.
+      if (entry.isDirectory()) descend(child, movedIn);
+      else if (movedIn) onChange(relative(projectDir, child));
+    }
+    if (movedIn && relative(projectDir, dir) === ".hyperframes") {
+      for (const manifest of STUDIO_SIGNATURE_MANIFEST_PATHS) onChange(manifest);
+    }
   };
   // `.hyperframes/` itself holds the two manifests the signature reads; nothing below it matters.
-  const descend = (dir: string) => {
+  const descend = (dir: string, movedIn = false) => {
     const rel = relative(projectDir, dir);
-    if (shouldWatchProjectFile(rel) || rel === ".hyperframes") watchDirectory(dir);
+    if (shouldWatchProjectFile(rel) || rel === ".hyperframes") watchDirectory(dir, movedIn);
   };
 
+  let parent: FSWatcher | null = null;
+  try {
+    parent = watch(dirname(projectDir), { persistent: true }, (event, name) => {
+      if (event !== "rename" || name?.toString() !== basename(projectDir)) return;
+      watchDirectory(projectDir);
+      onChange(".");
+    });
+    parent.on("error", () => parent?.close());
+  } catch {
+    // The project can remain watchable even when its parent is not.
+  }
   watchDirectory(projectDir);
   return () => {
+    parent?.close();
     for (const watcher of directories.values()) watcher.close();
     directories.clear();
   };
@@ -121,11 +144,8 @@ export function createProjectWatcher(projectDir: string): ProjectWatcher {
 
   try {
     closeTree = watchProjectTree(projectDir, (relativePath) => {
-      // The reload filter excludes all of `.hyperframes/`, but two files in
-      // there feed the preview signature and Studio writes one of them at
-      // runtime — dropping those at ingest left the CLI server's ETag stale
-      // until restart. Admit them here and let the reload listener re-apply
-      // its own filter, so what triggers a browser reload is unchanged.
+      // Studio's two manifests affect the signature despite the .hyperframes exclusion.
+      // Admit them here; the reload listener still applies its own filter.
       if (
         !shouldWatchProjectFile(relativePath) &&
         !affectsProjectSignature(projectDir, join(projectDir, relativePath))

packages/cli/src/server/studioServer.folderReplacement.test.ts

@@ -0,0 +1,132 @@
+import { mkdirSync, readFileSync, renameSync, writeFileSync } from "node:fs";
+import { join } from "node:path";
+import { afterEach, expect, it, vi } from "vitest";
+import { compositionsAffectedBy } from "@hyperframes/studio-server";
+import { createStudioServer, type StudioServer } from "./studioServer.js";
+import { cleanupStudioServerRoot, makeStudioServerRoot } from "./studioServerTestFixture.js";
+
+let root: string;
+let server: StudioServer | undefined;
+let reader: ReadableStreamDefaultReader<Uint8Array> | undefined;
+
+afterEach(async () => {
+  await reader?.cancel();
+  if (server) cleanupStudioServerRoot(server, root);
+});
+
+it.runIf(process.platform === "linux")(
+  "refreshes every composition and cached preview when its project directory is replaced",
+  async () => {
+    const fixture = makeStudioServerRoot("hf-preview-replace-");
+    root = fixture.root;
+    const { projectDir } = fixture;
+    const rootHtml = (label: string) => `<html><head></head><body>
+    <div data-composition-id="main" data-width="320" data-height="180">
+      <p>${label}</p><div data-composition-id="intro" data-composition-src="scenes/intro.html" data-start="0" data-duration="1"></div>
+    </div></body></html>`;
+    const scene = (
+      text: string,
+    ) => `<template><div data-composition-id="intro" data-width="320" data-height="180">
+    <h1>${text}</h1></div></template>`;
+    mkdirSync(join(projectDir, "scenes"));
+    writeFileSync(join(projectDir, "index.html"), rootHtml("Initial"));
+    writeFileSync(join(projectDir, "scenes/intro.html"), scene("Original"));
+    expect(compositionsAffectedBy(projectDir, "index.html")).toBeNull();
+    writeFileSync(join(projectDir, "index.html"), rootHtml("Unchanged root"));
+    server = createStudioServer({ projectDir, projectName: "film" });
+    expect(compositionsAffectedBy(projectDir, "index.html")).toEqual(["index.html"]);
+    const app = server.app;
+    const endpoint = "/api/projects/film/preview/comp/scenes/intro.html";
+    const before = await app.request(endpoint);
+    expect(before.status).toBe(200);
+    expect(await before.text()).toContain("Original");
+    const beforeTag = before.headers.get("etag");
+    expect(beforeTag).toBeTruthy();
+
+    const response = await app.request("/api/events");
+    reader = response.body!.getReader();
+    const deliveries: string[] = [];
+    const consume = async () => {
+      while (true) {
+        const next = await reader!.read();
+        if (next.done) return;
+        deliveries.push(new TextDecoder().decode(next.value));
+      }
+    };
+    const consuming = consume();
+    try {
+      const replacement = join(root, "replacement");
+      mkdirSync(join(replacement, "scenes"), { recursive: true });
+      writeFileSync(join(replacement, "index.html"), readFileSync(join(projectDir, "index.html")));
+      writeFileSync(join(replacement, "scenes/intro.html"), scene("Replacement"));
+      renameSync(projectDir, join(root, "previous"));
+      renameSync(replacement, projectDir);
+
+      await vi.waitFor(() => {
+        const event = deliveries
+          .join("")
+          .split("\n")
+          .find((line) => line.startsWith("data:") && line.includes('"path":"."'));
+        expect(event).toBeDefined();
+        expect(JSON.parse(event!.slice(5))).toMatchObject({
+          path: ".",
+          projectId: "film",
+          affectsPreview: true,
+          affectedCompositions: null,
+        });
+      });
+      const after = await app.request(endpoint, { headers: { "If-None-Match": beforeTag! } });
+      expect(after.status).toBe(200);
+      expect(after.headers.get("etag")).not.toBe(beforeTag);
+      expect(await after.text()).toContain("Replacement");
+
+      writeFileSync(join(projectDir, "scenes/intro.html"), scene("Later edit"));
+      await vi.waitFor(async () => {
+        const later = await app.request(endpoint);
+        expect(later.status).toBe(200);
+        expect(await later.text()).toContain("Later edit");
+      });
+    } finally {
+      await reader.cancel();
+      await consuming;
+    }
+  },
+);
+
+it.runIf(process.platform === "linux").each([
+  { kept: "a changed manifest", file: "studio-motion.json", content: '{"intro":{"opacity":0.5}}' },
+  { kept: "no manifest", file: "arbitrary.txt", content: "not a manifest" },
+])(
+  "refreshes the cached preview when a populated .hyperframes folder is replaced by one with $kept",
+  async ({ file, content }) => {
+    const fixture = makeStudioServerRoot("hf-preview-replace-manifests-");
+    root = fixture.root;
+    const { projectDir } = fixture;
+    writeFileSync(
+      join(projectDir, "index.html"),
+      `<html><body><div data-composition-id="main" data-width="320" data-height="180"></div></body></html>`,
+    );
+    mkdirSync(join(projectDir, ".hyperframes"));
+    writeFileSync(join(projectDir, ".hyperframes/studio-motion.json"), "{}");
+    server = createStudioServer({ projectDir, projectName: "film" });
+    const endpoint = "/api/projects/film/preview/comp/index.html";
+    const before = await server.app.request(endpoint);
+    expect(before.status).toBe(200);
+    const beforeTag = before.headers.get("etag");
+    expect(beforeTag).toBeTruthy();
+
+    const replacement = join(root, "next-manifests");
+    mkdirSync(replacement);
+    writeFileSync(join(replacement, file), content);
+    renameSync(join(projectDir, ".hyperframes"), join(root, "previous-manifests"));
+    renameSync(replacement, join(projectDir, ".hyperframes"));
+
+    await vi.waitFor(async () => {
+      const after = await server!.app.request(endpoint, {
+        headers: { "If-None-Match": beforeTag! },
+      });
+      expect(after.status).toBe(200);
+      expect(after.headers.get("etag")).not.toBe(beforeTag);
+    });
+  },
+);

packages/cli/src/server/studioServer.ts

@@ -425,7 +425,7 @@ export function createStudioServer(options: StudioServerOptions): StudioServer {
   const project: ResolvedProject = { id: projectId, dir: projectDir, title: projectId };
   let cachedProjectSignature: string | null = null;
   watcher.addListener((changedPath) => {
-    if (affectsProjectSignature(projectDir, join(projectDir, changedPath))) {
+    if (changedPath === "." || affectsProjectSignature(projectDir, join(projectDir, changedPath))) {
       cachedProjectSignature = null;
     }
   });