The ticket asked for two things. One of them is not reachable from the JVM, and saying
so is most of the value here.
**probeForConcat's catch arm cannot be provoked on this runtime.** Robolectric's
MediaExtractor never throws from setDataSource -- measured across four input shapes: an
unregistered content:// authority, a missing file://, a file of garbage bytes, and an
http:// URL. All four returned normally with trackCount = 0. So a failed read arrives as
an empty track list rather than as an exception and reaches the same
ConcatInput(null, null, 0, 0, 0) by the other road. The catch stays covered only by
ConcatEngineTest on a device. The test file says this rather than implying the arm is
handled.
**What is reachable, and was genuinely missing, is the span.** Both halves were already
covered and neither reached the other: MediaProbeTrackWalkTest pins what concatInputFrom
makes of a track list, ConcatPlannerTest's `an unknown codec is not treated as a match`
pins what the planner does with a hand-built ConcatInput(video = null). The planner's
safety rests on the probe really producing that shape, and the hand-built fixture would
go on passing if it stopped.
Measured rather than claimed: mutating concatInputFrom's initial `video` to a non-null
placeholder leaves ConcatPlannerTest green and turns this red. Dropping the planner's
video null guard turns both red -- so that half was already held, and this file does not
claim credit for it.
The coupling itself is worth writing down: ConcatPlanner guards video against a null codec
and audio not at all, and that asymmetry is correct rather than an oversight --
MediaProbe.shortName returns a non-null String, so a null audioCodec means the track is
absent and two clips with no audio really do match, while a null videoCodec means absent
*or* unreadable. The audio check is safe because the video guard fires first on a clip
nothing could read. Nothing held that.
555 -> 556 JVM tests, 0 failures. No production code changed.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
JMR-devandClaude Opus 5
5761faced6