web/playwright-native fails to install Chromium on Ubuntu 26.04 ("OS too new") — workaround via PLAYWRIGHT_HOST_PLATFORM_OVERRIDE

[basementbot]

Informational / workaround — not a blocker. Everything works after the steps below. Filing this to help anyone else on a very new (just-released or non-LTS) Linux distro who hits the same wall bringing up the web/playwright-native device.

Environment

• OS: Ubuntu 26.04 LTS ("resolute"), x86_64, kernel 7.0.0-27-generic
• Hardware: 2014 Intel MacBook Pro — worth noting the OS is newer than the tooling expects, not the hardware
• Trailblaze: 2026.07.02.2, installed via Homebrew on Linux (brew install block/tap/trailblaze)
• Java: none installed system-wide; the brew formula's bundled runtime was used (nice — no separate JDK needed)

Install (brew path worked cleanly)

brew install block/tap/trailblaze

All dependencies came in as prebuilt bottles (including ffmpeg). trailblaze --version and trailblaze device list both worked immediately.

The problem

Connecting the web device:

trailblaze device connect web/playwright-native

fails while Trailblaze installs Chromium:

Installing Playwright (this may take up to 2 minutes)...
  Downloading Chromium
  Error: ERROR: Playwright does not support chromium on ubuntu26.04-x64

It retries 3× with the same error and the device bind fails.

Root cause: Playwright ships prebuilt browser binaries only for OS versions in its known list. Ubuntu 26.04 is newer than the bundled Playwright knows about, so it refuses rather than hand over a possibly-incompatible binary.

Workaround

Point Playwright at the nearest supported build with PLAYWRIGHT_HOST_PLATFORM_OVERRIDE. The download happens inside the Trailblaze daemon, so the env var must be set when the daemon starts:

trailblaze app --stop
PLAYWRIGHT_HOST_PLATFORM_OVERRIDE=ubuntu24.04-x64 trailblaze app --headless
trailblaze snapshot --device web/playwright-native

Notes:

• The value must include the arch suffix — ubuntu24.04-x64. Bare ubuntu24.04 fails with does not support chromium on ubuntu24.04.
• Playwright then logs BEWARE: your OS is not officially supported by Playwright; downloading fallback build for ubuntu24.04-x64 and pulls Chrome for Testing 147.0.7727.15 (chromium v1217), which runs fine on 26.04 (all required libs are present — system Google Chrome already runs there).
• Once cached (~/.cache/ms-playwright/chromium-1217), the override is only needed again if a future version bump requires a new Chromium revision. Adding export PLAYWRIGHT_HOST_PLATFORM_OVERRIDE=ubuntu24.04-x64 to your shell profile makes it durable.

Result: trailblaze snapshot --device web/playwright-native → Snapshot captured, Browser: Chromium (desktop), viewport 1280×800. ✅

Two small observations (optional, for maintainers)

1. First-install race: the device connect / snapshot install-wait wrapper printed ✗ Device bind failed while the daemon was still downloading the (large, 3-part ~280 MB) browser bundle. A retry after the cache populated succeeded. The wrapper's timeout appears to race the daemon's actual install completion rather than tracking it.
2. Possible auto-fallback: Playwright already has the "unsupported OS → nearest build" path — it just needs the override set. Trailblaze could catch the does not support chromium on <os> error and auto-retry with the nearest ubuntuXX.04-x64, making this transparent for anyone on a brand-new or non-LTS distro.

Happy to provide full daemon logs if useful.

[basementbot]

One more thought now that I've poked at this a bit more — the env var is a fine band-aid on the user side, but the real fix probably lives in Trailblaze's build.

That does not support chromium on ubuntu26.04-x64 message comes straight out of Playwright's own bundled platform list, so whatever Playwright version we pin (the com.microsoft.playwright dependency in the Maven/Gradle setup) is what decides which distros get recognized. Newer Playwright releases keep adding entries to that table — plus they point at fresher Chrome-for-Testing builds — so just bumping the dependency to a more recent version would very likely make 26.04 work out of the box, no override needed.

Might be worth checking what version we're currently on and whether a newer one already lists ubuntu26.04. If it does, a dependency bump fixes this at the root and the whole workaround above becomes unnecessary. Happy to build off a branch with the bump and test a snapshot against my 26.04 machine to confirm before it goes anywhere.