NOT_BUILT is documented as the opt-out that narrows to nothing, and a change to
one of those devices' defconfigs does exactly that. Anything else in the same
directory did the opposite: targets_in() only ever returns devices CI builds, so
a directory holding nothing but opted-out devices came back empty and fell
through to the "is in no directory CI builds" widen. Touching a device CI
deliberately skips cost a full 107-device run.
$ echo devices/gk7205v200_rubyfpv_generic/br-ext-chip-goke/board/\
gk7205v200/gk7205v200.generic-fpv.config | python3 .github/scripts/ci-matrix.py --stdin
ci-matrix: 107/107 devices (needs_build=True) --- ... is in no directory CI builds
$ echo devices/gk7205v200_rubyfpv_generic/br-ext-chip-goke/configs/\
gk7205v200_rubyfpv_generic_defconfig | python3 .github/scripts/ci-matrix.py --stdin
ci-matrix: 0/107 devices (needs_build=False) --- nothing that reaches a build
Same device, same opt-out, opposite answers. #126 touches three NOT_BUILT
devices and is building all 107 because of it.
The empty result was carrying two meanings: "every device here is opted out" and
"this directory is not one I know". Only the second should widen. devices_in()
answers the second question -- it reads directory_of, which is built from every
defconfig in the tree rather than the built subset -- so an unrecognised
directory still widens, which is the half of the rule worth keeping.
Three self-test cases, one per meaning: a kernel config and an overlay file in a
NOT_BUILT device reach nothing, and a devices/ directory with no defconfig at
all still widens. With this, #126's own file list narrows from 107 to 23.
