The dominant merge-blocking flake was the "Set up Android SDK" step
(android-actions/setup-android v4.0.1) dying BEFORE the emulator starts:
Wrong version in preinstalled sdkmanager
Warning: ... preparing SDK package Android Emulator: Error reading Zip
content from a SeekableByteChannel.
Error: The process '.../sdkmanager' failed with exit code 1
Root cause: the action's default cmdline-tools version (20.0) rarely matches the
runner image's preinstalled one, so it logs "Wrong version in preinstalled
sdkmanager" and re-fetches cmdline-tools with NO checksum; it then runs its
default `sdkmanager tools platform-tools` install. Any of those downloads can be
a corrupt/truncated zip, which sdkmanager turns into an un-retried exit 1. v4.0.1
is the latest release, so this is fixed by configuration + hardening, not a bump.
Harden with verify -> reject -> retry, never trusting sdkmanager's exit code
alone, via a new stdlib-only helper .github/scripts/setup_android_sdk.py:
- bootstrap: download the pinned cmdline-tools zip, verify size + SHA-256
(authoritative pin, cross-checked against Google's published SHA-1), and
install it to $ANDROID_SDK_ROOT/cmdline-tools/20.0 -- the exact path
setup-android probes first, so the action reuses the verified tree and never
does its own unverified "Wrong version" re-download. A mismatch (corrupt OR
wrong version) deletes the bad zip + any half-extracted dir and re-downloads.
- install: sdkmanager --install with retry + backoff; on a corrupt package zip it
purges the partial/corrupt package dir (and sdkmanager's temp dirs) before
retrying, forcing a fresh download instead of a re-read.
- setup-android now runs with packages: "" (no flaky tools/platform-tools
install) and cmdline-tools-version: "14742923" (reuse the verified bootstrap).
- actions/cache restore + success-gated save so only a verified SDK is ever
cached (integrity gates the cache); shrinks the re-download/corruption surface.
Applied to every SDK-setup job (debug-build, unit-tests, static-analysis, e2e
matrix, e2e-preview). Emulator BOOT logic, #372 API-37 sharding, and #388
diagnostics are untouched. Pure-logic helpers are unit-tested
(test_setup_android_sdk.py, run by the traffic-control-tests job).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
JMR-devandClaude Opus 4.8
aa628831be