[Cosmos] [Embedding V0] _resolve_embeddings helper on hybrid-search aggregator (sync + async)

[ananth7592]

Embedding-resolution helper on the hybrid-search aggregator (sync + async)

Parent: 46729
Depends on: 46730, 46731

Goal

Add a single helper that takes the embeddingParameterMap from the plan, calls the customer-provided generator once with the full batch, and returns the augmented parameter list. No mutation of caller state.

Scope

Add (sync) on _HybridSearchContextAggregator:

def _resolve_embeddings(self):
    embedding_map = self._partitioned_query_ex_info.get_embedding_parameter_map()
    if not embedding_map:
        return
    generator = self._options.get("embeddingGenerator")
    if generator is None:
        raise ValueError(
            "Query requires embedding generation but no embedding_generator "
            "was passed to query_items."
        )
    keys, texts = zip(*sorted(embedding_map.items()))   # stable order
    vectors = generator.generate_embeddings(list(texts))
    if len(vectors) != len(texts):
        raise ValueError(
            f"embedding_generator returned {len(vectors)} vectors for {len(texts)} texts"
        )
    for i, v in enumerate(vectors):
        if v is None:
            raise ValueError(f"embedding_generator returned a null vector at index {i}")
    extra = [{"name": k, "value": list(v)} for k, v in zip(keys, vectors)]
    base = list(self._parameters or [])
    self._parameters = base + extra

Mirror in aio/hybrid_search_aggregator.py:

async def _resolve_embeddings_async(self):
    ...
    vectors = await generator.generate_embeddings_async(list(texts))
    ...

Add a type guard at the async entry point: if a sync EmbeddingGenerator is passed (no generate_embeddings_async), raise TypeError early with an actionable message.

Non-goals

• Do NOT yet call this from _run_hybrid_search; that lives in 46733.
• Do NOT add the diagnostics span here; that lives in 46734 (but the call-site for the span will be inside this helper).

Files touched

• sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/hybrid_search_aggregator.py
• sdk/cosmos/azure-cosmos/azure/cosmos/_execution_context/aio/hybrid_search_aggregator.py

Acceptance

• Helper is non-mutating for the no-op case (no map → no parameter changes).
• Sort-stable (same map → same parameter order).
• Raises ValueError with clear messages on cardinality mismatch / null entry / missing generator.
• Async path raises TypeError if a sync generator is passed.
• 100 % unit-test coverage of the helper (covered by 46735).