ci: run e2e-browser inside Playwright Docker image (#2053)

* ci: cache Playwright browsers in e2e-browser job

`playwright install` repeatedly hung post-download on GitHub Actions
runners (Chromium zip finished in <1s, then ~15min of silence until
the step timeout). Restoring `~/.cache/ms-playwright` from a
yarn.lock-keyed cache makes the install step a no-op on warm runs and
sidesteps the hang entirely. First run on a new lockfile still has to
populate the cache, but subsequent shards/runs reuse it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* ci: run e2e-browser inside Playwright Docker image

`yarn install:browsers` (i.e. `playwright install --with-deps`)
repeatedly hung post-download on plain ubuntu-latest runners — the
Chromium zip finished in <1s, then ~15min of total silence until the
step timeout fired. An earlier attempt to cache `~/.cache/ms-playwright`
didn't help because every shard starts cold simultaneously and
`actions/cache` only saves on workflow success.

Use the official `mcr.microsoft.com/playwright` image (the same approach
e2e-react already uses via its `run-in-docker.sh`): browsers and system
deps are pre-installed at /ms-playwright, so the `install:browsers`
step becomes unnecessary and the flake disappears.

The image tag must match `@playwright/test` in
packages/browser/e2e-tests/package.json; bump alongside any Playwright
upgrade.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* ci: set HOME=/root for Playwright tests in Docker

Inside `mcr.microsoft.com/playwright` we run as root, but GH Actions
overrides `\$HOME` to `/github/home` (owned by `pwuser`). Firefox
refuses to launch under those conditions ("Running Nightly as root in
a regular user's session is not supported"). Playwright surfaces the
exact workaround in its error message: set `HOME=/root`.

Chromium and webkit shards passed; only Firefox tests were affected.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: whitphx

.changeset/e2e-browser-docker.md

@@ -0,0 +1,4 @@
+---
+---
+
+CI-only: run the e2e-browser Playwright job inside the official Playwright Docker image (`mcr.microsoft.com/playwright`) so the `yarn install:browsers` step is no longer needed. Sidesteps an intermittent post-download hang in Playwright's `install --with-deps` that had been timing out shards.

.github/workflows/e2e.yml

@@ -76,6 +76,21 @@ jobs:
 
     runs-on: ubuntu-latest
 
+    # `yarn install:browsers` (i.e. `playwright install --with-deps`)
+    # repeatedly hung post-download on plain ubuntu-latest runners: the
+    # Chromium zip finished in <1s, then ~15min of silence until the step
+    # timeout fired. Running the job inside Playwright's official Docker
+    # image — which ships browsers pre-installed at /ms-playwright with
+    # all system deps already there — sidesteps that install step
+    # entirely. (Same approach as e2e-react below.)
+    #
+    # Image tag must match `@playwright/test` in
+    # packages/browser/e2e-tests/package.json — bump alongside any
+    # Playwright upgrade.
+    container:
+      image: mcr.microsoft.com/playwright:v1.57.0
+      options: --ipc=host # Recommended by Playwright for Chromium shared memory.
+
     strategy:
       fail-fast: false
       matrix:
@@ -94,14 +109,10 @@ jobs:
           node-version-file: ${{ env.node-version-file }}
 
       - name: Set up the e2e-tests environment
-        # `yarn install` (registry) and `yarn install:browsers` (Playwright CDN)
-        # have intermittently hung in GitHub Actions runners and burned the
-        # whole 6h job timeout. Cap the step so a hang fails fast and the
-        # shard can be rerun.
+        # Cap as a safety net; browsers come from the container image,
+        # so this is just `yarn install`.
         timeout-minutes: 15
-        run: |
-          yarn install
-          yarn install:browsers
+        run: yarn install
         working-directory: packages/browser/e2e-tests
 
       - name: Build demos
@@ -125,6 +136,11 @@ jobs:
         working-directory: packages/browser/e2e-tests
         env:
           BUILD_DIR: ${{ runner.temp }}/artifacts/browser/package/build
+          # Inside the Playwright container we run as root, but GH Actions
+          # overrides $HOME to /github/home (owned by pwuser). Firefox
+          # refuses to launch in that state; restore HOME=/root.
+          # Playwright's own error message points at this exact fix.
+          HOME: /root
 
       - name: Upload blob report to GitHub Actions Artifacts
         if: ${{ !cancelled() }}