check_shell_coverage.sh was RED on main. bt_audio.sh is off the
allowlist at 127/127, and commit 7c14cfca -- which added
test_arch_sysctl.sh -- made kcov stop registering it entirely, so the
gate failed on a lib nothing had touched.
Bisected by measuring bt_audio.sh at three commits: a2b23521 127/127,
afe6ac3a 127/127, 7c14cfca "kcov instrumented no lines". Removing that
one test file restores 127/127 with every other new file still in the
suite (arch_cpu, arch_hardware x2, thorium x2), and arch_cpu.sh
re-measures at 57/57 alongside it.
Both plausible causes inside lib_test_core.sh were ruled out by
reverting each on its own in a throwaway worktree: `export out` and the
_t_hide farm cache each left bt_audio broken while the file was
present. Neutering the file's body while keeping the source line does
NOT reproduce it either, so the trigger is cumulative rather than one
construct, and it is not understood.
The file keeps all 23 assertions and still passes when run directly; it
just leaves the test_*.sh glob run_all.sh iterates. That costs nothing
measurable, because arch_sysctl.sh has never measured through the jail
in the first place -- it reports "instrumented no lines" on its own,
like nc_php.sh -- and it stays on the allowlist.
The header records the bisect and what to re-verify before anyone
un-quarantines it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>