[jiaran-king]

Problem

When the EPD proxy cannot rewrite raw media, the decoder can receive a different source UUID from the encoder. A video with use_audio_in_video=True also produces multiple feature entries, which singleton response matching can discard. Mooncake can prepare additional transfers without reporting their actual IDs, and request cleanup can cancel a transfer another request is loading.

Changes

• Prepare source UUIDs on a request copy shared by encoding and raw fallback, preserving user UUIDs and --no-rewrite. Collect every EC handle independently of placeholder rewriting. Supported metadata rewrites remain enabled; inputs that cannot be reconstructed safely use whole-request raw fallback.
• Report actual prepared transfer bindings, including distinct transfers with the same hash. Track requests that prepare or reuse a binding while preserving transfer-ID deduplication.
• Protect in-flight loads during request completion/free callbacks, retaining the existing load deadline. Track pending unallocated feature demand separately from allocated cache entries so staggered features can accumulate READY results. Retire only outputs with neither allocation nor pending demand through the existing resident pool and reclamation path.

This is a correctness fix. It does not add complete audiovisual metadata-only input support, eliminate decoder raw-media preprocessing, or claim a performance improvement.

Validation

Rebased onto upstream main 5efbf0886a7110ae0801b9540e3072e89a23eb36 and reran:

.venv/bin/python ../EPD_RAW_FALLBACK_R4_20260917/cpu_bootstrap.py \
  tests/v1/ec_connector/unit/test_mooncake_scheduler.py \
  tests/v1/ec_connector/unit/test_epd_proxy_retry.py \
  tests/v1/ec_connector/unit/test_epd_proxy_round_robin.py -q

52 passed total: 34 Proxy + 18 scheduler/worker cases. The bootstrap is a local evidence harness outside this PR: it loads whole production modules, substitutes unused GPU/runtime imports, and uses mocked native registration/control calls. Lifecycle cases execute real CPU tensors, reservation/memory-pool classes and worker load methods. This is component validation, not native Mooncake/CUDA E2E. The committed test files can be run normally in a configured vLLM test environment.

Coverage includes raw identity and request immutability, multi-feature handle retention, shared-binding completion in both orders, borrowed primary/extra transfers during finish/free, timeout cleanup, staggered readiness, pending borrowers, and bounded resident reclamation after abort or eviction.

Default pre-commit hooks, manual mypy-3.12, and git diff --check passed on the changed files. Earlier component evidence on baseline 3bb782621492711485dc86791b5978128783814a also exercised production hashing and ECExample file I/O: fixed synthetic decoded video/audio inputs missed both output keys before the fix and loaded equal test tensors afterward. No real-model evaluation or native audiovisual GPU smoke has been completed.

Draft status

Remaining validation: real audiovisual E/PD identity and output reuse, native Mooncake load/cancel behavior under overlapping requests, and staggered feature readiness. Human review and relevant test execution remain required before readiness.

Open-PR searches did not identify the same fix. #57095 addresses proxy HTTP batching, #56242 cross-encoder Store caching, and #47302 a separate Store connector; this patch is based directly on main and includes none of those PRs' changes.

AI assistance was used.

[mergify]

Documentation preview: https://vllm--57275.org.readthedocs.build/en/57275/

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[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @jiaran-king.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork