[JarryShaw]

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• Searched for similar pull requests
• Followed the coding style (make pylint, make mypy, make isort) — run on the touched files: isort clean; mypy/pylint report nothing in the changed lines
• make test passes, and a test case covers the change — only the modules listed below, not the full suite
• Added a changelog entry — N/A, added centrally after the wave

What is the purpose of your pull request?

• fix — corrects a defect

---

Description of your pull request and other information

Closes #1148. SchemaField.unpack passed its "undeclared" -1 on as the nested schema's length, so __length__ started negative and every sub-field warned. It now measures what is left in the buffer and passes that as a declared length. Passing None would be simpler, but prepare() would then turn a buffer that has run out into its quiet StreamEOFError ("end of capture"). Measured: that would change a truncated LOCATOR_SET from FieldValueError to StreamEOFError. Fixed-length items are unchanged.

Also rewrites the stale ContextRequestOption note in pcapkit/protocols/schema/internet/mh.py (docstring only; code AST unchanged), which justified the opaque requests run with the -1 warnings this PR removes. The opaque run is kept because a nested-schema list would only warn on an entry that overruns the option and zero-pad its value, where MH._read_opt_cr raises ProtocolError.

probe (SchemaWarning count)	before	after
HIP LOCATOR_SET, 2 / 3 locators	12 / 18	0 / 0
MH CGA Parameters, 1 item	6	0
HIP LOCATOR_SET, truncated by 10	FieldValueError + 17	FieldValueError + 6
MH CGA, truncated by 3	FieldValueError + 11	FieldValueError + 7
fixed-length item declared 3 < schema 4	2	2 (unchanged)

New tests/corekit/test_fields_misc_schema_length_1148_unit.py: 5 passed. Without the fix, 3 tests fail (5 subfailures). With the None variant, the truncation test fails with StreamEOFError. Passing (one module per process): test_fields_misc, _misc_packet_context, _collections, _field, test_option_roundtrip_unit, test_hip_unit, test_hip_locator_set_length_unit, test_mh_unit, test_ipv4_unit, test_httpv2_payload_length_unit, plus tests/project (385 passed, 1 skipped).

[JarryShaw]

Cross-review verdict on 1e78f8acf: NEEDS CHANGES (ran on Sonnet; author Opus). One stale comment needs fixing.

The note at pcapkit/protocols/schema/internet/mh.py:1371-1383 (ContextRequestOption) says a length-less SchemaField is passed -1 and warns once per field. After this PR that is false. Reword it to describe the new behaviour, or remove it.

Everything else checks out:

• Buffers: the remainder is measured with tell/seek exactly as prepare already does. Parsed items and the final position are identical on bytes, BytesIO, a real file and SeekableReader.
• Fixed lengths: a declared length takes the unchanged path.
• Truncation: truncated input still raises FieldValueError. Swapping in a None sentinel fails the guard test.
• Tests: 19 protocol modules give identical pass counts. Every frame's info hash is identical across 7 captures.
• Speed: neutral. A 44,100-frame capture took 16.63 s before and 16.56 s after, and its 7,200 warnings per run drop to 0.

[JarryShaw]

Cross-review verdict on e233a7390: GOOD TO GO (ran on Sonnet; author Opus, round 2)

The reviewer's round 1 was GOOD TO GO with the stale mh.py note as a nit. I made it NEEDS CHANGES myself, because the PR made that comment false. It is now fixed.

• Note claims, both probed. A valid ContextRequestOption with type 22 and type 19 entries parses with 0 warnings. A length-less nested list that overruns only warns and zero-pads, while _read_opt_cr raises ProtocolError (mh.py:4497-4502). So the opaque-run design still has a reason.
• AST guard: mh.py is equal to round 1 once bare strings are stripped. The delta is docstring-only, and misc.py and the tests are unchanged.

[github-actions]

Coverage: 88.75% (unit tier, Python 3.14, e233a7390, Unit Tests run success)

Package	Statements	Missed	Branches	Partial	Cover
pcapkit (top level)	104	4	20	4	93.55%
pcapkit/const	18757	1035	2342	846	90.23%
pcapkit/corekit	1878	91	580	22	94.34%
pcapkit/dumpkit	136	0	40	0	100.00%
pcapkit/foundation	2425	145	842	34	92.56%
pcapkit/interface	112	7	40	5	92.11%
pcapkit/protocols	15659	188	3944	163	98.18%
pcapkit/toolkit	487	65	144	1	85.42%
pcapkit/utilities	429	4	122	4	98.55%
pcapkit/vendor	4409	2359	1006	158	42.84%

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