Fix: use synced hash table + sha256_cbor for token-based lookup (same process NONE_HASH)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

third_party/vllm/vllm/distributed/kv_transfer/kv_connector/v1/mooncake/mooncake_utils.py

@@ -225,27 +225,19 @@ class MooncakeBootstrapServer:
     def _lookup_by_tokens(
         self, token_ids: list[int], num_tokens: int | None
     ) -> tuple[list[int | None], list[int]]:
-        """Look up cached blocks by computing hashes on C's side."""
+        """Look up cached blocks by computing hashes using the synced hash table.
+
+        Computes block hashes from token_ids using the same hash function
+        as the scheduler, then looks up in the synced _hash_table.
+        """
         from vllm.v1.core.kv_cache_utils import (
+            BlockHash,
             hash_block_tokens,
-            make_block_hash_with_group_id,
             NONE_HASH,
         )
+        from vllm.utils.hashing import sha256_cbor
 
-        bp = self._block_pool
+        block_size = self._kv_info.get("block_size", 512) if self._kv_info else 512
-        block_size = bp.block_size if hasattr(bp, 'block_size') else 512
-        # Use C's own hash function
-        hash_fn = bp._hash_fn if hasattr(bp, '_hash_fn') else None
-        if hash_fn is None:
-            # Fallback: try to get from coordinator
-            coord = bp.coordinator if hasattr(bp, 'coordinator') else None
-            if coord and hasattr(coord, '_caching_hash_fn'):
-                hash_fn = coord._caching_hash_fn
-
-        if hash_fn is None:
-            logger.warning("Cannot find hash function on block pool")
-            return [], []
-
         n = num_tokens or len(token_ids)
         n = min(n, len(token_ids))
         num_blocks = n // block_size
@@ -256,18 +248,16 @@ class MooncakeBootstrapServer:
 
         for i in range(num_blocks):
             block_tokens = tuple(token_ids[i * block_size:(i + 1) * block_size])
-            block_hash = hash_block_tokens(hash_fn, prev_hash, block_tokens, None)
+            block_hash = hash_block_tokens(sha256_cbor, prev_hash, block_tokens, None)
             prev_hash = block_hash
 
-            # Look up in C's block pool
+            bid = self._hash_table.get(block_hash.hex())
-            key = make_block_hash_with_group_id(block_hash, 0)
+            if bid is not None:
-            block = bp.cached_block_hash_to_block.get_one_block(key)
+                block_ids.append(bid)
-            if block is not None:
+                pinned_ids.append(bid)
-                block_ids.append(block.block_id)
-                pinned_ids.append(block.block_id)
             else:
                 block_ids.append(None)
-                break  # prefix match stops
+                break
 
         return block_ids, pinned_ids