[JarryShaw]

• Searched for similar pull requests
• Followed the coding style (make pylint, make mypy, make isort)
• make test passes, and a test case covers the change
• Changelog entry: N/A — centralised in docs(changelog): shared 1.5.0 changelog — long-lived, merges last (#610, #616, #617, #618, #620) #657

What is the purpose of your pull request?

• fix — corrects a defect

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Description of your pull request and other information

TCP reassembly used sys.maxsize as the open bound of its hole descriptor list. On GraalPy and 32-bit builds that is 2**31 - 1, which lies inside TCP's sequence space. So holes went wrong past 2**31, and a FIN'd stream was never seen as whole (#1959).

• New pcapkit.foundation.reassembly.data.tcp.HOLE_OPEN_BOUND (2**63 - 1). It stays an int, as HoleDescriptor is typed, and is JSON- and plist-safe in both signs. It equals 64-bit sys.maxsize, so nothing changes where it already worked.
• It and its negation replace every former sys.maxsize site in reassembly/tcp.py. It is documented on HoleDescriptor and the TCP reassembly page.
• New regression tests patch sys.maxsize to 2**31 - 1 and drive sequence numbers above 2**31. They fail without the fix.

Closes #1959

[JarryShaw]

GOOD TO GO at c6c370fda. A Sonnet review checked the bound against the sequence space. _unwrap keeps each step within 2**31 of its reference, and every hole first/last is a PSN plus a payload length, so 2**63 - 1 is unreachable in practice. No sys.maxsize remains in pcapkit/, and the four sites use the bound symmetrically. The hole list is never dumped. versionadded:: 1.5.0 matches the unreleased 1.5.0b13. Without the fix, the tests fail on the reported symptom ([(3235779125, 2147483647)]). With it, 320 passed across reassembly, traceflow, tier guard, docstring and public-API tests.

[github-actions]

Coverage: 90.07% (unit tier, Python 3.15, c6c370fda, Unit Tests run success)

Package	Statements	Missed	Branches	Partial	Cover
pcapkit (top level)	104	2	20	2	96.77%
pcapkit/const	19597	881	2618	867	92.11%
pcapkit/corekit	2504	70	792	36	96.54%
pcapkit/dumpkit	276	3	100	3	98.40%
pcapkit/foundation	2916	164	1016	34	93.59%
pcapkit/interface	138	7	52	5	93.68%
pcapkit/protocols	17411	224	4580	189	98.10%
pcapkit/toolkit	872	177	298	8	77.18%
pcapkit/utilities	522	2	158	4	99.12%
pcapkit/vendor	4431	2341	1018	156	43.64%

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