VideoEngine uses unguarded POSIX stat in native Windows build

[localai-bot]

Defect

Current main at cefacd2d00cb9b4776331cd213116773cd97f811 adds src/vllm/multimodal/video_engine.cpp with an unconditional <sys/stat.h> include and two ::stat calls. The configured Windows portability checker rejects all three sites, so the native MSVC release lanes cannot compile this shared VideoEngine surface.

Reproduction

python3 scripts/check-windows-portability.py --root . --build-dir build-review-fix
ERROR: src/vllm/multimodal/video_engine.cpp:21: unguarded POSIX include/call reaches Windows
ERROR: src/vllm/multimodal/video_engine.cpp:59: unguarded POSIX include/call reaches Windows
ERROR: src/vllm/multimodal/video_engine.cpp:64: unguarded POSIX include/call reaches Windows

Required outcome

Use the standard C++ filesystem surface for directory/existence queries, preserving error behavior and detector semantics. Do not guard or exempt the POSIX path. Add/port focused behavior coverage if existing VideoEngine tests do not distinguish regular files, directories, missing paths, and filesystem errors.

This regression blocks the Windows binary release work in PR #524.

[localai-bot]

Cross-link: #646 was filed ~3 minutes before this one for the same break, from the reviewer side. I have scoped #646 down to the part this issue does not cover — check-windows-portability.py runs in no CI job, hook, or preflight — so the two do not overlap.

This issue owns the fix (the _WIN32 path in video_engine.cpp:21,59,64); #646 owns wiring the orphaned checker in, with cefacd2d0 as its red-before evidence and your fix as the green-after.

One datum that may help scope yours: CMakeLists.txt:919 puts video_engine.cpp in the main source list with no WIN32 guard, so it reaches everything linking the library, including the server target on both Windows lanes. The load-bearing symbol is S_ISDIR — MSVC does ship <sys/stat.h> and _stat, so the include alone would survive.

Timing evidence that it is a compile break rather than the pre-existing #584 runtime crash: PRs based pre-#641 fail windows-msvc-cpu after ~22 min having built; PRs based on cefacd2d0 fail in ~1 min.