c2patool exits non-zero both when an asset carries no manifest and when the
binary itself fails, and run_optional_tools only ever substring-matched the
output. A probe that died before main() produced has_manifest: False with no
other signal, so inspect reported has_c2pa: false -- the same answer it gives
for a genuinely clean asset.
Reproduced on Apple Silicon: service/Dockerfile pins a multi-arch base digest,
so an arm64 host builds an arm64 image while still installing the
x86_64-unknown-linux-gnu c2patool release (upstream publishes no linux-aarch64
build). c2patool dies with "rosetta error: failed to open elf at
/lib64/ld-linux-x86-64.so.2" and exit -5, and /capabilities kept reporting
c2patool: true because which() only finds the file.
Exposure is largest for PDF, where inspect_pdf documents exiftool and c2patool
as the more reliable detectors. For JPEG/PNG the native APP11 and PNG-chunk
scans still catch hard-bound C2PA, so there it costs corroboration rather than
the only signal.
- run_optional_tools marks a run conclusive only when it found a manifest or
said in so many words that there is none; anything else sets ok: False
- inspect_image and inspect_pdf surface that as an inconclusive note, worded
to land in the informational confidence bucket
- /capabilities probes each tool's version flag instead of trusting which()
Issues #1 and #3 fixed the opposite direction of this same function ("No claim
found" matching "claim"). This closes the false-negative side.
Co-authored-by: Italo Rodrigues <italo@pvwi.com.br>
Co-authored-by: Guillaume Meyer (The Opinionated Man) <1385518+guillaumemeyer@users.noreply.github.com>
