Real-world plant() crashed with OSError [Errno 7] Argument list too
long when an artifact (honeydoc HTML / DOCX / PDF) base64-encoded
into the sh -c script body exceeded the kernel's argv limit (typically
128KB-2MB depending on the host).
Fix: keep the script trivial ('mkdir -p ... && base64 -d > path && ...')
and stream the encoded bytes through 'docker exec -i ... sh -c'
stdin instead. _run() grew an optional stdin_bytes parameter that's
piped into proc.communicate(input=...). The stdin path covers
arbitrarily large artifacts.
Tests updated:
- test_plant_argv_and_base64_round_trip now asserts the docker -i
flag is present and the base64 payload reaches stdin (and notably
is NOT in the script body).
- _FakeProc.communicate accepts input=None across the board so the
patched fast path no longer trips on the new kwarg.