The spike commits already implemented the N=2 shard matrix (numShards/
shardIndex via -Pandroid.testInstrumentationRunnerArguments.*), per-shard
test-retry parity, adb start-server before the boot loop, and shard-suffixed
artifact names. This drops the SPIKE / DRAFT "do not merge as-is" framing from
the ci.yml comments and reframes docs/perf/api37-e2e-sharding-spike.md from a
feasibility spike into the adopted design, so the change is mergeable as-is.
Also fixes the doc's section 3a example, which showed 1-based shardIndex values
[1, 2]; shardIndex is 0-based (0..numShards-1) and the implementation correctly
uses matrix.shard: [0, 1] -- [1, 2] would run an empty bucket and silently drop
half the suite.
Fan-in unchanged and verified: ci-passed still lists e2e-preview once; GHA
matrix aggregation makes its result `failure` if either shard fails, so both
shards must pass for the gate to go green. Branch protection requires the
"CI passed" context (not the per-leg "E2E (API 37 preview) (N)" check names),
so no branch-protection change is needed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Folds the #370 root-cause finding into the spike. The stable `e2e` matrix
retries its test run once; `e2e-preview` runs connectedDebugAndroidTest exactly
once, so a flaky test self-heals on API 29-36 but wedges the required gate on
API 37 (e.g. #370's SignaturesScreenTest teardown race).
Doc: adds risk item 9 (retry-parity gap + its sharding interaction — per-test
flake is NOT amplified by sharding unlike boot flake, and a per-shard retry
costs only B + T/N; framed mitigation-not-fix) and two §6 recommendations
(retry parity, mirrored into api37_e2e.py; adb start-server before the boot
loop).
PoC (ci.yml): per-shard single test retry (::warning:: on retried-but-passed)
+ adb start-server before the boot loop. The api37_e2e.py retry mirror stays a
documented recommendation (local path needs a real-emulator validation this
spike did not boot). Still DRAFT, not auto-merged.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Feasibility spike for sharding the e2e-preview job (the hand-provisioned
API 37 / google_apis_ps16k 16 KB-page emulator), CI's longest leg
(~16.4-17.6 min). docs/perf/api37-e2e-sharding-spike.md breaks the leg into
fixed overhead B ~8.3 min (setup + boot + Gradle daemon/config/compile/install)
vs parallelizable test execution T ~8.8 min, models B + T/N for N=2/3/4, and
recommends N=2 (~17.1 -> ~12.7 min, ~28% off the critical path) capped by the
API 30 matrix wall (~12.0 min) beyond N=3.
DRAFT PoC (do NOT merge as-is): converts e2e-preview to a strategy.matrix.shard
[0, 1] fan-out passing AndroidJUnitRunner numShards/shardIndex through the
existing -Pandroid.testInstrumentationRunnerArguments.* channel (no GMD, no
orchestrator, no Gradle change). Artifact names gain a shard suffix;
ci-passed still lists e2e-preview once (matrix fan-in keeps the single gate).
Local preflight stays single-emulator. Relates to #258.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
JMR-devandClaude Opus 4.8