[StoneDC]

What

Adds positive-length wcsncpy tests through 128 units with shorter, exact and longer sources. It checks full-unit zero padding, nonterminated truncation, returned base, source preservation and guarded write extents.

Integrate the existing #13220 fix at e9f09f54fabb6408d3e2711b8df10c10112ab00e and current recorded main. The failed macOS write-watch jobs stopped in CMake configuration because execute-fault and read-fault were each registered twice. This head includes the original prerequisite commit, removing the duplicate block while retaining all 18 distinct tests. No parallel fix is introduced, no test assertion is weakened, and no timeout is changed.

This PR's fixture is byte-identical to the previous published head 8671223b16d01ad643e993fec0326bbc50fd57f9. The extra topic-relative CI change is the existing prerequisite's five-line registration deletion. Proposed landing order is #13220 first, then this independent topic. The submitted head already includes the fix, so its new CI can test it while the prerequisite PR remains open.

Original topic rationale and earlier overlap evidence (historical snapshots)

Adds positive-length wcsncpy tests through 128 units with shorter, exact and longer sources. It checks full-unit zero padding, nonterminated truncation, returned base, source preservation and guarded write extents.

Implementation basis: Public string/memory contract: https://github.com/freebsd/freebsd-src/blob/833d39bd2e38421a14ea489a956261a0fa993fbc/lib/libc/string/wmemchr.3. The fixture calls the actual production function(s) through the existing public Api.hpp and constructs expected results separately from immutable input snapshots, membership tables or standard C++ range algorithms. No production function body or firmware object is copied into the fixture.

Known limits: Uses char16_t as already declared by the repository; it does not infer console object layouts, validate Unicode, add Annex K policies or replace existing zero-length tests.

Source/schema: core/libs/prx/libc/src/Strings.cpp core/libs/prx/libc/include/Api.hpp

Exact topic head 8671223b16d01ad643e993fec0326bbc50fd57f9 is one independent commit on main 51c31ea17e9f66cb36fe9655ec31c81610bfcfc9. The current-main repository overlap checker against 51c31ea17e9f66cb36fe9655ec31c81610bfcfc9 reported no confirmed overlap. It could not finish comparisons for these older PRs already conflicting with main: #5021, #6085, #7081, #7447, #7715, #8150, #8965, #11628, #11661, #11689, #11698, #11947, #12688, #12700, #12965. Their shared-file diffs were reviewed separately. 13 scoped file changes projected onto main and then combined with this topic without a new conflict; 2 peer file changes already conflict with main and are not claimed automatically mergeable. They do not provide this command or test matrix. Registration uses a separate target/name and there is no landing-order dependency. Changes to shared registration before landing need a refreshed merge/test check. Functional overlap remains independent; the shared macOS CI prerequisite is #13220. The twenty current topic heads are also merged into tested integration cedab5157a32822332671c90812c6780d05157e8.

Shared CI prerequisite: #13220 fixes main's duplicate write-watch fault-test registration. The macOS write-watch jobs currently fail in CMake configuration before compiling or executing this PR's fixture. This PR needs that existing fix first for the shared macOS checks; no duplicate implementation or unrelated source change is added here.

Tested

Exact submitted head f27454e88a02dd9c9f0510d3afb0aa72378f7e87. Recorded main 6a3afa4deb18ea58a90efb8040fff8c60e4f2aab; prerequisite #13220 e9f09f54fabb6408d3e2711b8df10c10112ab00e. Both and the previous published topic head are ancestors. The fixture and topic assertions remain unchanged.

Fresh native validation uses combined commit 099d1af76d85818308412d7dd864f8bb4a1cd013, containing all 13 exact submitted heads, on Windows 11 / MinGW GCC 15.2 / CMake 4.3.1 and non-root Ubuntu 26.04 / WSL / GCC 15.2 / CMake 4.2.3. This is explicit combined-commit validation, not 13 separate native product builds. Every individual fixture blob matches that combined tree; pairwise main/prerequisite merges are clean.

• Full Ninja Release configuration with BUILD_TESTING=ON; build the 13 topic test targets plus guest_string_tests, guest_wide_string_tests and guest_string_compare_tests with their real library dependencies. The existing cached dependency sources/gitlink pins and FFMPEG_PREBUILT_DIR mechanism are reused.
• Run the 13 registered topic CTests and guest_strings, guest_wide_strings, guest_string_compare: 16/16 pass on each OS, zero skips. This PR's registered guest_wcsncpy_extent is included exactly once. No timeout was raised.
• Direct standalone write-watch CMake regression on each OS: recorded main's CMakeLists.txt fails configuration with both duplicate-name diagnostics. Replacing only that file with the integrated test(libc): register the macOS write watch fault tests once #13220 version configures successfully and enumerates 18 unique tests, with execute-fault/read-fault exactly once each. This verifies the failing configuration stage and test preservation; it does not claim a local macOS write-watch runtime.
• Per-head current-main conventions with this complete body and diff whitespace checks pass. Combined public-header, script-registration and CTest skip-policy audits pass. Fixture hashes and prerequisite ancestry are checked before publication.

The combined native target build is not the complete default product build. No local macOS/WASM, PS5/title/GPU or firmware validation is claimed. Old red CI belongs to older heads without the prerequisite; new-head hosted CI starts after publication and remains pending until it actually completes. The prerequisite's external branch is unchanged.

Exact composition of the fresh native validation

#13310 ab8eeea15ea0dcb8aabe95e656a041963f8e4e8a, #13313 1ec676984f08d1ee65496d0d1c487a9fecb8ec49, #13314 1c8549945e9657645da7ce5a98693d50e85b5685, #13317 442aef391ffaec2c9cfe1d098c84dde5f19cd292, #13319 dab492c88b6bd8093c351b1726db02ad91af39ab, #13320 f27454e88a02dd9c9f0510d3afb0aa72378f7e87, #13378 8bb9ed3e152ea1611fe8216f25dd03c7830f2818, #13379 9b39858ef369da4f3eb01e4137e3f932a478ebd2, #13380 6083413b06d03a34e498629da942b8ec40ab7a9f, #13381 cf303f4142403e370f807813b99fc5aa087ad72b, #13391 15fbf68aa97b2617cd03ae94f033020028edeac6, #13394 cb3188c2b1f36700f882311191f86b897c4f01cb, #13395 8165ef480879e5eed57eb8f631abc924aed02ec7

Earlier author-reported validation (historical heads; not new results)

Topic head: 8671223b16d01ad643e993fec0326bbc50fd57f9. Combined integration: cedab5157a32822332671c90812c6780d05157e8, based on main 51c31ea17e9f66cb36fe9655ec31c81610bfcfc9. Ubuntu/WSL GCC 15.2, CMake 4.2.3, Python 3.14.4; Windows MinGW GCC 15.2, CMake 4.3.1, Python 3.14.3.

The registered test calls the actual libc through canonical headers, using OS-protected pages and real input/output buffers. A separate exact-head control compiled the whole relevant production source unit with this fixture: unchanged production code passed, and the fixture rejected an intentional production-function defect. This is a source-unit control, separately from the product build below.

Registered CTest guest_wcsncpy_extent passed on Linux and Windows as part of the filtered twenty-topic run: ctest --test-dir <build> -R <20-topic-pattern> -j 8 -V --output-on-failure, 20/20 passed on each platform, zero skips. cmake --build <linux-full-build> --parallel 8: complete default Linux product build passed. Windows used the full configuration and built the sixteen affected libc test targets plus relinker with --parallel 8; a complete default Windows build is not claimed. Conventions, whitespace, script registration and the public-header declaration/umbrella audit passed. No PS5, title or GPU validation run is claimed. macOS, WASM execution and hosted full-build CI are not reported as passed.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed under Silent stubs in their library's technical debt file
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: test(libc): register the macOS write watch fault tests once #13220
• Fixes: none
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: yes

[MarcZX10]

Reviewed — looks good

The exact-head test is registered and checks the bounded-copy padding, truncation, return value, source preservation, and guarded write extent; no blocking issue was found in the source review.

What I ran

Reviewed PR head 8671223b16d01ad643e993fec0326bbc50fd57f9 against current main 58d5af7daa8087d2ffbdb50ae6e0db3cb6a88e48; the merge preview was clean (tree 0a3636f682677a35e49c006cbcd00607efc0990e). Environment: Debian 12 x86-64, Python 3.11.2, Git 2.39.5, GCC 12.2.0. I did not build or run C++ tests locally. Linux and Windows test results below are author-reported for a combined integration containing this exact topic head, not independently run by me. Hosted PR checks were queued at the final refresh.

git diff --check 58d5af7daa8087d2ffbdb50ae6e0db3cb6a88e48...8671223b16d01ad643e993fec0326bbc50fd57f9
python3 tools/check_conventions.py --base 58d5af7daa8087d2ffbdb50ae6e0db3cb6a88e48 --head 8671223b16d01ad643e993fec0326bbc50fd57f9 --title 'test(libc): guard UTF-16 bounded copy padding and truncation' --body /tmp/pr-13320-body.md
python3 tools/pr_stack_check.py 13320 --repo boykopovar/AnyPS5 --output-dir /tmp/anyps5-13320-stack-current
python3 tools/pr_test_quality.py --root /tmp/anyps5-review-13320 --json core/libs/prx/libc/CMakeLists.txt core/libs/tests/GuestWcsncpyExtent.cpp
gh pr checks 13320 -R boykopovar/AnyPS5

Results

Check	Result
Diff whitespace	Passed; no output from git diff --check.
Conventions and PR template	Passed against current main.
Current-main merge preview	Passed; clean tree 0a3636f682677a35e49c006cbcd00607efc0990e; no declared dependencies.
Test registration/source review	The target and CTest are registered in the changed CMake file. Assertions cover zero, shorter, exact, and longer inputs; destination terminator padding; truncation; return pointer; unchanged source; and eight prefix units.
Test-quality heuristic	Reported a possible test registration issue; manual inspection confirmed registration via ${LIBS_INCLUDE_DIR}/tests/GuestWcsncpyExtent.cpp.
Author-reported tests	The author reports guest_wcsncpy_extent and a filtered 20-topic CTest set passed 20/20 on Linux and Windows in an integration containing this exact topic head, plus an exact-head intentional-defect control. I did not independently run these.
Hosted CI	All six jobs were queued at final refresh; no hosted result is claimed.
Build and local C++ execution	Not run locally.

Unedited local command output

git diff --check produced no output.

Conventions:

All conventions checks passed.

Test-quality heuristic:

{
  "findings": [
    {
      "path": "core/libs/tests/GuestWcsncpyExtent.cpp",
      "line": 1,
      "kind": "possible-unregistered-cpp-test",
      "message": "Changed C++ test source path was not found literally in CMake files; inspect registration, generated source lists, and workflow coverage."
    }
  ],
  "negative_control_candidates": [],
  "limits": [
    "Heuristics can miss weak assertions and can flag valid tests; inspect every finding.",
    "A test that passes against base is not by itself proof that the PR test is inadequate.",
    "Negative controls are only candidates until the test actually runs against base and fails by assertion rather than import/setup error."
  ]
}

Stack check:

# PR stack check — fresh

Target: https://github.com/boykopovar/AnyPS5/pull/13320
Target branch tip: `58d5af7daa8087d2ffbdb50ae6e0db3cb6a88e48`
All heads unchanged: **True**
Dependency order: #13320

## Individual merge previews

- PR #13320: **clean** against current base; head `8671223b16d01ad643e993fec0326bbc50fd57f9`; changed paths: none reported

## Dependency relationships

No declared PR dependencies were found in the target PR chain.

Hosted checks at final refresh:

conventions	pending	0	https://github.com/boykopovar/AnyPS5/actions/runs/41056381420/job/124064846097
eligibility	pending	0	https://github.com/boykopovar/AnyPS5/actions/runs/41056381618/job/124064845389
intake	pending	0	https://github.com/boykopovar/AnyPS5/actions/runs/41056381457/job/124064845998
labels	pending	0	https://github.com/boykopovar/AnyPS5/actions/runs/41056381562/job/124064846693
library-portability	pending	0	https://github.com/boykopovar/AnyPS5/actions/runs/41056381926/job/124064846140
report	pending	0	https://github.com/boykopovar/AnyPS5/actions/runs/41056381544/job/124064844534

Negative control

Assertion	Mutation reported by author	Result
Fixture detects an incorrect bounded-copy implementation	Author reports an intentional production-function defect in the exact-head source-unit control	Author reports the fixture rejected the mutation; I did not independently run this control.

Findings

Blocking

None found in the reviewed source.

Non-blocking

The C++ test and mutation control were not independently run here; I relied on the author's reported integration results. Hosted PR checks were still queued at the final refresh.

Sources

• Registered guest_wcsncpy_extent target.
• Guarded test cases and assertions.
• Production wcsncpy_nid_postfix implementation.

Not verified

No local build or C++ execution; no independent Linux/Windows run; no macOS, WASM runtime, title, or console testing. Hosted checks were queued.

[github-actions]

Some comparisons could not be completed because a pull request conflicts with the base branch. Review these shared files manually before concluding that there is no overlap.

Pull request	Shared files not compared
PR 5021	core/libs/prx/libc/CMakeLists.txt
PR 6085	core/libs/prx/libc/CMakeLists.txt
PR 7081	core/libs/prx/libc/CMakeLists.txt
PR 7447	core/libs/prx/libc/CMakeLists.txt
PR 7715	core/libs/prx/libc/CMakeLists.txt
PR 8150	core/libs/prx/libc/CMakeLists.txt
PR 8965	core/libs/prx/libc/CMakeLists.txt
PR 10324	core/libs/prx/libc/CMakeLists.txt
PR 11628	core/libs/prx/libc/CMakeLists.txt
PR 11661	core/libs/prx/libc/CMakeLists.txt
PR 11689	core/libs/prx/libc/CMakeLists.txt
PR 11698	core/libs/prx/libc/CMakeLists.txt
PR 12682	core/libs/prx/libc/CMakeLists.txt
PR 12688	core/libs/prx/libc/CMakeLists.txt
PR 12700	core/libs/prx/libc/CMakeLists.txt
PR 12965	core/libs/prx/libc/CMakeLists.txt

[StoneDC]

Investigated the failed macOS checks on unchanged head 8671223b16d01ad643e993fec0326bbc50fd57f9:

• write-watch (macos-15-intel)
• write-watch (macos-15)

Both logs stop in core/libs/tests/write_watch/CMakeLists.txt:42 during CMake configuration: write_watch_execute-fault and write_watch_read-fault are each registered twice on main. This happens before this PR's fixture is compiled or run; it is not a boundary-test assertion failure.

The existing fix is #13220 at e9f09f54fabb6408d3e2711b8df10c10112ab00e. I added it as the shared macOS CI prerequisite in this PR's description/checklist. This follow-up does not change code or claim the red jobs passed. Once #13220 lands, a fresh build against the updated main is needed; simply rerunning the old merge snapshot would retain the duplicate registration.

The independent functional test scope is unchanged; the remaining macOS CI blocker is the shared registration fix.

AI-assisted: yes.

[StoneDC]

Integrated the existing shared CI fix at new head f27454e88a02dd9c9f0510d3afb0aa72378f7e87 on recorded main 6a3afa4deb18ea58a90efb8040fff8c60e4f2aab.

#13220's original commit e9f09f54fabb6408d3e2711b8df10c10112ab00e is now an ancestor, and its duplicate-registration deletion is present in this branch. The previous macOS failure was in configuration, before the fixture ran. The new head can configure with the fix already included; the checklist still declares #13220 first in landing order. The external prerequisite branch is unchanged.

Fresh local verification:

• Combined commit 099d1af76d85818308412d7dd864f8bb4a1cd013 contains all 13 exact updated topic heads. The fixture in this PR is byte-identical to its previous published head and the combined tree; no test assertion or timeout is changed.
• Windows/MinGW and Linux: rebuilt the 13 affected native targets and three related string targets, with real library dependencies. All 16 registered CTests pass on each OS, zero skips, including guest_wcsncpy_extent exactly once.
• Direct configuration regression on both OSes: main's unchanged standalone write-watch CMake file fails with the two duplicate-name errors. Replacing only that file with the integrated prerequisite configures successfully and lists 18 unique tests, with execute-fault/read-fault once each. This verifies configuration/test preservation, not a local macOS runtime.
• Per-head conventions with the complete PR description, whitespace, prerequisite ancestry, fixture retention, combined public-header/registration and skip-policy audits pass. This is focused native target validation, not a complete default product/PS5/GPU run.

Hosted-check snapshot at 2026-10-30T17:36:36+00:00 (UTC): 2 pending. Current-head checks. Earlier red checks belong to heads without the prerequisite; new-head CI remains pending until it completes. Please re-check this integrated head.

AI-assisted: yes.