BRIEF-P5E section 3 item 4 calls for three negative controls. Running them showed E1
(MOBILEGL_IPC_VERB_BARRIER=0) had THREE problems stacked, with the first two hiding the third.
This fixes the first two and narrows the third into something executable.
1. It selected a case that can never run in this lane.
E1's selection regex is (Triangle|ClearThenReadPixels), and the positive control gl added
under ID-115, TriangleScenario.TheServerStampedAVerbBoundaryOnThisDrawingFrame, matches it.
That case reads a PipeStats window out of the lane's OWN private log, so it runs only in the
strict-arming lane and skips everywhere else BY DESIGN, whatever this knob is set to. ID-62
makes a SKIPPED SELECTED entry a hard failure - correctly, because a control that silently
loses its subjects proves nothing. So E1 reported "the knob killed the pre-flight, not the
entry" while the knob was in fact working: four other selected entries went red with the
abort in the same run.
The fix excludes a case that can never run here, rather than teaching E1 to tolerate skips,
which would have thrown ID-62 away. ctest -R is POSIX ERE with no negative lookahead, so
run_control gains a fifth positional: a real ctest -E.
2. ctest and the log helper disagreed about who was selected.
run_control passed -E to ctest, but split_log_paths.py still filtered on -R alone, so it
counted the excluded entry as selected and then reported it as "did not run". The helper now
reads the same exclusion (SPLIT_LOG_EXCLUDE). An env var rather than another positional
because the helper's positional layout differs per mode - and a control whose two halves
disagree about its own subject set is exactly the class of bug this script exists to
prevent.
3. The real defect. ID-122 was right, and there is now a sharper statement of it.
With the first two fixed E1 is still red, and red on "10 selected entries did not fail": 4
of 14 went red, AND Fatal{BarrierViolation} appears ZERO times in the entire run - those 4
are red for other reasons. The evidence E1 demands has never appeared. The Fatal at
ClientSession.cpp:878 asserts an overlap OBSERVED BY THE APPLY THREAD, and at
MOBILEGL_IPC_BATCH_WAITS's default of 1 the barrier is taken at the next residual-reading
verb, so that overlap does not happen.
Further: with run-ahead armed, VERB_BARRIER=0 ALSO disarms run-ahead (it is the first
conjunct of RunAheadArmed(), ID-114), so the arm this knob produces is neither lockstep nor
run-ahead - it cannot serve as the negative control for either side.
E1 needs its falsification target REDEFINED, not its threshold adjusted. Left as a named
outstanding item, recorded in ID-122 and the open items.
E1's counting rule ("every selected entry must go red") is deliberately NOT relaxed here: it
was set to block the "any non-zero exit counts" false green, and loosening it before knowing
what E1 should falsify would only trade one false green for another.
swung0x48