fix(sctp): rebuild a Host Name parameter without a NUL terminator as captured (#1482)

[JarryShaw]

• Searched for similar pull requests
• Followed the coding style (make pylint, make mypy, make isort) — not run locally
• make test passes, and a test case covers the change — new tests cover it; targeted suites only, not the full make test
• Added a 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

The reader keeps a Host Name Address parameter's name as captured. _make_param_hostname rejected any name without a NUL terminator, so SCTP.from_data(info) raised ProtocolError: [Param 11] invalid format on a packet that parsed.

The fix follows the existing if <record> is not None: … else: <validate keyword> maker idiom (e.g. ipv4.py:1522). The terminator check now runs only on a user name keyword (pcapkit/protocols/transport/sctp.py:2970-2973), and a parsed record rebuilds as read. A hand-built make() without a terminator still raises. Docstrings in transport/sctp.py and data/transport/sctp.py are updated to match. schema/transport/sctp.py (#1481) is untouched.

New tests/protocols/transport/test_sctp_hostname_nul_unit.py covers the #1482 repro, a terminated name, every cut at offsets 44–66 of the #1481 multi-chunk packet, and make() with abcdefgh. Through both info and info.to_dict(), all rebuild cases fail on origin/main and pass here. Results: test_sctp*.py 66 passed; test_transport_edge_roundtrip_unit.py 6 passed; tests/project 419 passed, 1 skipped. repr(info.to_dict()) hashes over the 23 files in examples/captures are identical to origin/main.

Closes #1482

[JarryShaw]

Verdict: GOOD TO GO at dcc08bdc0. Cross-reviewed on Sonnet; the author ran on Opus.

• The fix: a captured Host Name now rebuilds as captured. I re-ran the fix(sctp): a Host Name parameter without a NUL terminator parses but cannot be rebuilt #1482 repro (abcdefgh, no terminator): it raises on main and rebuilds byte-exactly at head. The new tests give 25 failed on origin/main sources and 5 passed, 29 subtests at head.
• Names tried: abcde, abcdefgh, a\0b and empty all rebuild byte-exactly at head through .data, from_data(info) and from_data(info.to_dict()), with the captured length field. abcd\0 and ab\0\0\0 were already byte-exact on main and still are.
• The user path still checks: a hand-built make() with an unterminated or empty name still raises. When param is given, it takes precedence over the name keyword, as in _make_param_ipv4.
• Regression checks: the per-capture to_dict() hashes are identical across all 23 captures. The SCTP and edge tests give 72 passed, 286 subtests; tests/project gives 419 passed.
• Overlap: its files are disjoint from fix(sctp): accept a final parameter or cause short of its padding (#1479) #1481's.

Non-blocking: the comment on pcapkit/protocols/schema/transport/sctp.py:593 still says the name includes a NUL terminator. That file belongs to #1481, so I'll correct the comment in whichever of the two lands second.

[github-actions]

Coverage: 89.57% (unit tier, Python 3.14, dcc08bdc0, Unit Tests run success)

Package	Statements	Missed	Branches	Partial	Cover
pcapkit (top level)	104	4	20	4	93.55%
pcapkit/const	18795	958	2356	871	90.99%
pcapkit/corekit	2107	93	672	27	94.60%
pcapkit/dumpkit	242	2	88	2	98.79%
pcapkit/foundation	2648	98	930	48	94.80%
pcapkit/interface	112	7	40	5	92.11%
pcapkit/protocols	17086	239	4628	192	97.97%
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.