fix(browser-preview): detect any cached Playwright Chromium revision

apps/server/src/browser-preview/browser-preview-manager.test.ts

@@ -1,7 +1,7 @@
 import { ThreadId } from "@t3tools/contracts";
 import { describe, expect, it } from "vitest";
 
-import { BrowserPreviewManager } from "./browser-preview-manager.ts";
+import { BrowserPreviewManager, playwright_chrome_candidates } from "./browser-preview-manager.ts";
 
 const threadId = ThreadId.make("thread-browser-preview");
 
@@ -75,3 +75,31 @@ describe("BrowserPreviewManager", () => {
     expect(tickets.map((ticket) => manager.resolve_ticket(ticket))).toEqual([null, null]);
   });
 });
+
+describe("playwright_chrome_candidates", () => {
+  it("prefers the newest revision and ignores unrelated cache entries", async () => {
+    const fs = await import("node:fs/promises");
+    const os = await import("node:os");
+    const path = await import("node:path");
+    const cacheDir = await fs.mkdtemp(path.join(os.tmpdir(), "gits-playwright-cache-"));
+    try {
+      for (const entry of ["chromium-1208", "chromium-1228", "firefox-1489", ".links"]) {
+        await fs.mkdir(path.join(cacheDir, entry), { recursive: true });
+      }
+
+      const candidates = playwright_chrome_candidates(cacheDir);
+
+      expect(candidates[0]).toBe(path.join(cacheDir, "chromium-1228", "chrome-linux64", "chrome"));
+      expect(candidates).toContain(
+        path.join(cacheDir, "chromium-1208", "chrome-linux64", "chrome"),
+      );
+      expect(candidates.join(" ")).not.toContain("firefox");
+    } finally {
+      await fs.rm(cacheDir, { recursive: true, force: true });
+    }
+  });
+
+  it("returns nothing when the cache directory is absent", () => {
+    expect(playwright_chrome_candidates("/nonexistent/ms-playwright")).toEqual([]);
+  });
+});

apps/server/src/browser-preview/browser-preview-manager.ts

@@ -1,6 +1,7 @@
 // @effect-diagnostics nodeBuiltinImport:off globalDate:off - external CLI boundary and expiring viewer tickets.
 import { execFile } from "node:child_process";
-import { existsSync } from "node:fs";
+import { existsSync, readdirSync } from "node:fs";
+import { join } from "node:path";
 import { randomUUID } from "node:crypto";
 import { promisify } from "node:util";
 
@@ -55,6 +56,36 @@ export interface BrowserPreviewManagerOptions {
   readonly run?: BrowserPreviewRun;
 }
 
+// Playwright installs each Chromium build under its own `chromium-<revision>` directory and
+// prunes old ones, so pinning revisions goes stale on the next `playwright install`.
+const PLAYWRIGHT_CHROME_RELATIVE_PATHS = [
+  "chrome-linux64/chrome",
+  "chrome-linux/chrome",
+  "chrome-mac/Chromium.app/Contents/MacOS/Chromium",
+] as const;
+
+export function playwright_chrome_candidates(cache_dir: string): ReadonlyArray<string> {
+  let entries: ReadonlyArray<string>;
+  try {
+    entries = readdirSync(cache_dir);
+  } catch {
+    return [];
+  }
+
+  return (
+    entries
+      .flatMap((entry) => {
+        const revision = /^chromium(?:_headless_shell)?-(\d+)$/u.exec(entry)?.[1];
+        return revision === undefined ? [] : [{ entry, revision: Number(revision) }];
+      })
+      // Newest revision first: Playwright keeps older builds around until they are pruned.
+      .sort((left, right) => right.revision - left.revision)
+      .flatMap(({ entry }) =>
+        PLAYWRIGHT_CHROME_RELATIVE_PATHS.map((relative) => join(cache_dir, entry, relative)),
+      )
+  );
+}
+
 function resolve_browser_path(): string | undefined {
   if (process.env.GSD_BROWSER_BROWSER_PATH) {
     return process.env.GSD_BROWSER_BROWSER_PATH;
@@ -64,8 +95,9 @@ function resolve_browser_path(): string | undefined {
     "/usr/bin/google-chrome",
     "/usr/bin/google-chrome-stable",
     "/usr/bin/chromium",
-    `${process.env.HOME ?? ""}/.cache/ms-playwright/chromium-1223/chrome-linux64/chrome`,
-    `${process.env.HOME ?? ""}/.cache/ms-playwright/chromium-1208/chrome-linux64/chrome`,
+    ...(process.env.HOME
+      ? playwright_chrome_candidates(join(process.env.HOME, ".cache", "ms-playwright"))
+      : []),
   ];
   return candidates.find((candidate) => existsSync(candidate));
 }