When a file is truncated between fstat and the snapshot read, we now return
(None, data, actual_size) instead of (None, None, actual_size). This preserves
the captured bytes so the body path serves the immutable snapshot instead of
re-reading the fd after headers are committed.
This closes the second-order TOCTOU window: if the file shrinks AGAIN between
the first read and body transmission, Content-Length (from actual_size) and
body length (from snapshot) can never diverge.
Changes:
- api/routes.py:18494: return None, data, actual_size (preserve snapshot)
- tests: remove unused original_read (ruff F841)
- test_shrink_again_during_body_transmission_200: 200 advertised 6 / wrote 6
- test_shrink_again_during_body_transmission_range_206: 206 advertised 4 / wrote 4
happy5318
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