openvax / topiary / 34803217055-1

92%

master: 92%

Pull #309

github

Report a missing input file's message, not its errno (5.56.0 regression)

Reviewing 5.56.0's own diff turned up a bug it introduced. Its CLI
handler unwrapped e.args[0] for every exception it caught, to strip the
extra layer of repr quoting str() puts on a KeyError subclass:

    message = e.args[0] if e.args else str(e)

The version before it guarded that unwrap with isinstance(e, KeyError).
Dropping the guard applied it to OSError too, whose args are
(errno, strerror) - so args[0] on a missing input file is the bare
integer 2. A user passing a nonexistent --peptide-csv got

    topiary: error: 2

instead of

    topiary: error: [Errno 2] No such file or directory: '...'

Reproduced through main() before changing anything. The unwrap is now
scoped to CachedPredictorCoverageError specifically, the only exception
on this path whose str() needs it; everything else renders through
str() exactly as it did before 5.56.0, which is correct by construction
rather than by enumeration.

The test gap that let this through is closed too:
test_main_reports_a_missing_input_file_readably asserts the strerror
text and the path both reach stderr, and explicitly pins the errno-only
output this regressed to. Confirmed failing against 5.56.0.

Claude-Session: https://claude.ai/code/session_015pMD1uiTztbB2bTQ1FkY8m

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