[EncoderCacheManager] Remove unnecessary copy

[lgeiger]

Purpose

#13173 introduced this copy. Since then self.get_cached_input_ids changed to always return a new set so no need to copy it again.

vllm/vllm/v1/core/encoder_cache_manager.py

Lines 196 to 208 in 180fba6

	def get_cached_input_ids(self, request: Request) -> set[int]:
	"""Get all cached multimodal input IDs for a request.
	Returns the set of input IDs whose `mm_hash` exists in the cache map.
	This includes entries that are currently unreferenced (and thus present
	in `freeable`); for such entries, freeing for this request will be a
	no-op.
	"""
	return {
	input_id
	for input_id in range(len(request.mm_features))
	if request.mm_features[input_id].identifier in self.cached
	}

vllm/vllm/v1/core/encoder_cache_manager.py

Lines 392 to 393 in 180fba6

	def get_cached_input_ids(self, request: Request) -> set[int]:
	return set(range(len(request.mm_features)))

Test Plan

CI

[gemini-code-assist]

Code Review

This pull request removes a redundant .copy() call when getting cached input IDs within the EncoderCacheManager.free method. The get_cached_input_ids method already constructs and returns a new set, so an additional copy is unnecessary. The change is correct and safely improves efficiency by avoiding an extra object allocation. I have reviewed the changes and found no issues.