W2: the join state mapping, and a crash the seam exposed #163

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JMR-dev merged 2 commits from test/join-state-mapping into main 2026-08-29 15:49:04 +00:00
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Author SHA1 Message Date
JMR-dev 1ff5c4463c Merge remote-tracking branch 'origin/main' into test/join-state-mapping 2026-08-29 10:39:55 -05:00
JMR-devandClaude Opus 5 fea480b000 W2 (#155): the join state mapping, and a crash the seam exposed
The join-side twin of W1, deliberately the same shape -- one refactor done twice,
and letting the two diverge would cost more than the duplication. Five arms had
never been chosen by any test, for the same reason: a real ConcatWorker only ever
reaches a terminal state with well-formed output.

WHAT THE SEAM TURNED UP. This line was in the SUCCEEDED arm:

    info.outputData.getString(ConcatWorker.KEY_STRATEGY)
        ?.let(ConcatStrategy::valueOf) ?: ConcatStrategy.REENCODE

`valueOf` throws IllegalArgumentException on a name this build does not define,
and this runs inside a `viewModelScope` collect with no handler -- so it is not a
Failed state, it takes the process down.

Not theoretical. WorkManager keeps finished work about a week, so a downgrade or
rollback hands this build a job enqueued by another one -- the premise
`WorkerEnumFallbackTest` and `JobTags` are both written on. `ConcatWorker` writes
`result.strategy.name`, so a build that added a third strategy would leave this
one crashing on its own completed joins.

The codebase had already made this exact fix one file over, and said why:

    // Looked up rather than `valueOf` -- see the same three reads in
    // ConversionWorker. This one is above the try as well, so a format name this
    // build does not define used to throw past the catch

The matching read on the ViewModel side had not been changed with it. It is now
`ConcatStrategy.entries.firstOrNull { it.name == name } ?: REENCODE`.

PROVEN RATHER THAN ASSERTED. Restoring `valueOf` and running the new test:

    RED: an unknown strategy name is read as a re-encode rather than thrown
      java.lang.IllegalArgumentException: No enum constant
      org.libremediaconverter.model.ConcatStrategy.SMART_CONCAT_V2

REENCODE is the conservative default rather than an arbitrary one: it is the
answer for inputs that do not match, so a job whose strategy cannot be read is
described as the more cautious of the two rather than claimed as a lossless
stream copy. The mutation to STREAM_COPY reddens two tests.

Eight mutations, all red:

  unknown strategy -> STREAM_COPY            | 2 tests
  runAttemptCount ignored, both directions   | 2 tests
  success with no path -> empty Joined       | 1 test
  BLOCKED unfolded from RUNNING              | 1 test
  blank error no longer falls back           | 1 test
  cancellation ignores the caller's state    | 1 test

516 -> 530 tests, 87.7% -> 88.0% line, 70.4% -> 71.3% branch. Gate green:
assembleDebug, testDebugUnitTest, compileDebugAndroidTestKotlin, ktlintCheck,
detekt, lintDebug.

Stacked on W1 (#162), which this mirrors and should not land before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-29 10:37:13 -05:00