Review follow-up on the previous two commits.
Widening the control-message except tuple put the callback dispatch
inside it, so an _on_new_cycle() that raised ValueError, TypeError or
AttributeError sent a perfectly good control packet to the legacy PNG
decoder -- which reported it as an image decode error and buried the
real fault. Split the two: whether the payload parses as JSON decides
frame vs control message, a second guard covers reading the fields of an
attacker-shaped body, and the callback fires outside both. It still
cannot kill the receive thread; the loop's own handler catches it, and
now says what actually went wrong.
The logo download's temp file was a fixed "<name>.part". Two plugins
asking for the same logo at once would interleave writes into it,
publish the mixture, or delete each other's partial. mkstemp gives each
download its own name in the same directory, so os.replace stays atomic.
Its descriptor is adopted by fdopen before the request runs, since a
request that raises before the write would otherwise leak the fd --
quietly, because load_logo_with_download swallows that.
Two test fixes: the oversized-frame test replaced PIL.Image.open
process-wide, the same hazard the clock helper documents, and Ruff B007
on an unused loop variable.
Full suite: 3355 passed, coverage 54%.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NohXi78cwsAKtN1sCfxjUh
Claude
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