forked from unom/punktfunk
enricobuehler
ed4bbc6b0b
`video_vulkan.rs` was fenced with the other thirteen GPU/FFI backends, but it never belonged with them: its four sites are not ash calls, they are RAW POINTER DEREFERENCES inside the two FFmpeg `lock_queue`/`unlock_queue` callback trampolines — exactly the case where the lint pays, and where a proof carries an argument instead of restating a signature. Both bodies had none at all. They keep `unsafe extern "C"`: FFmpeg invokes them with a `*mut AVHWDeviceContext`, which is a real contract, now written down. What was missing is why the dereference chain is sound, and it is worth stating because it is not obvious — the trampoline casts between pf_ffvk's `AVHWDeviceContext` and ffmpeg-sys's (the same C struct declared twice), reads `user_opaque`, and dereferences it as a `QueueLock`. That pointer borrows `VkCtxStorage::_queue_lock`, an `Arc<QueueLock>` whose field doc already says it exists to outlive every call the context can make. The proof now connects those two facts, so a future edit to the storage's lifetime has something to contradict. With that, the file needs no exemption and the workspace `deny` covers it: 14 fenced files -> 13. This is what removing a fence is supposed to look like — the sites that are worth narrowing get narrowed, and the exemption disappears rather than being renewed. Verified on .21: fmt + `clippy --workspace --all-targets -- -D warnings` + the feature-gated `-p pf-encode` step, all rc=0 with no allow in the file.