[JarryShaw]

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• Followed the coding style (make pylint, make mypy, make isort)

• make test passes, and a test case covers the change — tests added; ran tests/corekit, tests/foundation/test_extraction*.py, the PyPCAPFile engine, tests/project, the docstring contract and the tier guard, not the full suite

• Added a changelog entry under docs/source/changelog/ and regenerated CHANGELOG.md, if the change is user-visible — N/A — centralised in docs(changelog): shared 1.5.0 changelog — long-lived, merges last (#610, #616, #617, #618, #620) #657

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copy and pickle build a PeekableStream without __init__. __getattr__ then forwarded __setstate__ to an unset _stream, whose own lookup re-entered __getattr__ until RecursionError. It now refuses _stream and every dunder, so the proxy's protocols are never the stream's.

Semantics: copy.copy shares the stream (one position); copy.deepcopy and pickle copy it, so they succeed exactly when the stream's own do — BytesIO from protocol 2, an open file never. NamedStream and SeekableReader were already sound and are unchanged.

tests/corekit/test_io_peekable_stream_copy_1524_unit.py: 7 tests; 9 of 11 results fail on 945c3c3d8 (8 RecursionError, 1 forwarded __setstate__).

Closes #1524

[JarryShaw]

Verdict: GOOD TO GO at 696cf1a26. Cross-reviewed on Sonnet; the author ran Opus.

• Fail-before: with main's corekit/io.py, the new test file gives 9 failed, 2 passed; at the head, 7 passed, 12 subtests passed. I re-ran both myself. Each guard clause (dunder, _stream) has its own failing test under mutation.
• No forwarding lost: implicit dunder lookups never went through __getattr__, and no code in pcapkit/, tests/, docs/ or examples/ calls a forwarded dunder explicitly. extract(fin=BytesIO) matches extract(fin=path) on 8 captures (default, dpkt) and 6 (pypcapfile, 3.11).
• Semantics: copy shares the stream and position; deepcopy gives an independent stream at the same position; pickle 2–5 round-trips; 0/1 fail with the stream's own TypeError.
• Based on current main (b6b95bc8e), no conflict; CI 27 ok / 0 fail, 7 still running.

Nits, not blocking: the __getattr__ comment could name __getstate__ (3.10 and older) and __deepcopy__ as the reachable cases rather than __setstate__; and test_pickle_below_protocol_2_fails_as_the_stream_does passes on main too, so it is a guard, not a regression test.

[github-actions]

Coverage: 90.09% (unit tier, Python 3.14, 696cf1a26, Unit Tests run success)

Package	Statements	Missed	Branches	Partial	Cover
pcapkit (top level)	104	4	20	4	93.55%
pcapkit/const	18795	842	2356	756	92.09%
pcapkit/corekit	2204	67	712	34	96.26%
pcapkit/dumpkit	258	2	90	2	98.85%
pcapkit/foundation	2650	98	934	42	94.98%
pcapkit/interface	112	7	40	5	92.11%
pcapkit/protocols	17009	229	4574	189	98.04%
pcapkit/toolkit	539	74	168	3	84.58%
pcapkit/utilities	431	4	124	4	98.56%
pcapkit/vendor	4409	2342	1006	157	43.25%

Per-file detail: the coverage-html artifact of this run.