Root cause: intermittently the launched activity window has has-window-focus=false
for the WHOLE instrumented run, so Espresso's RootViewPicker (onView().check(),
Intents.intended(), pressBack(), focus-dependent clipboard) times out after 10s and
fails EVERY focus-dependent test at once while the ~280 pure-Compose semantics tests
(which don't need window focus) pass. A failing E2E (35) leg's logcat (PR #470, run
28985259521) shows has-window-focus=true ZERO times across the whole session and both
the first attempt and the once-retry fail identically -- a persistent environmental
state, not a per-test transient. The prior mitigation, a single fire-and-forget
`adb shell input keyevent 82` (MENU) right after boot, is too weak: MENU no longer
dismisses the modern (API 30+) keyguard and, delivered before SystemUI/keyguard comes
up, is simply dropped -- so the insecure keyguard / non-interactive display persists
and no app window ever takes focus.
Fix: a single shared helper, .github/scripts/emulator_focus_gate.py, invoked
identically by BOTH E2E jobs (the e2e API 29-36 matrix AND e2e-preview API 37) and by
the local preflight runners (local_instrumented.py / api37_e2e.py), so it cannot drift.
It wakes the display (KEYCODE_WAKEUP), dismisses + disables the keyguard
(wm dismiss-keyguard, locksettings set-disabled true), keeps the screen on
(svc power stayon true + max screen_off_timeout), zeroes the animation scales, then
polls dumpsys power/window until the device is interactive AND a real window holds
input focus (mCurrentFocus non-null) -- re-nudging each iteration -- before the suite
runs. Applied uniformly, this also gives e2e-preview the animation-disable the matrix
already had. The gate is soft (bounded wait, then proceeds with a ::warning:: and the
final device state) and non-fatal (`|| true`), preserving #454's guarantee that the
unlock never aborts the boot; it leaves #454's manual boot, #460's path-filter and
#464's wedge-capture untouched.
The pure readiness parser is unit-tested by test_emulator_focus_gate.py (run by the
traffic-control-tests job). Determinism is validated by this PR's own matrix run.
Closes#468
JMR-dev