From d7f4638157a9d8e17a506dd8b1bae96e768fb9db Mon Sep 17 00:00:00 2001
From: Legion345 <harelasaraf@gmail.com>
Date: Tue, 28 Apr 2026 13:08:04 -0700
Subject: [PATCH] fix(storage): stop ChromaDB from crashing when reopening an
 existing palace

---
 mempalace/backends/chroma.py | 22 +++++++++++++---------
 tests/test_backends.py       | 26 ++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 9 deletions(-)

diff --git a/mempalace/backends/chroma.py b/mempalace/backends/chroma.py
index 048f760..85684ac 100644
--- a/mempalace/backends/chroma.py
+++ b/mempalace/backends/chroma.py
@@ -8,6 +8,7 @@ from pathlib import Path
 from typing import Any, Optional
 
 import chromadb
+from chromadb.errors import NotFoundError as _ChromaNotFoundError
 
 from .base import (
     BaseBackend,
@@ -1037,15 +1038,18 @@ class ChromaBackend(BaseBackend):
         ef_kwargs = {"embedding_function": ef} if ef is not None else {}
 
         if create:
-            collection = client.get_or_create_collection(
-                collection_name,
-                metadata={
-                    "hnsw:space": hnsw_space,
-                    "hnsw:num_threads": 1,
-                    **_HNSW_BLOAT_GUARD,
-                },
-                **ef_kwargs,
-            )
+            try:
+                collection = client.get_collection(collection_name, **ef_kwargs)
+            except _ChromaNotFoundError:
+                collection = client.create_collection(
+                    collection_name,
+                    metadata={
+                        "hnsw:space": hnsw_space,
+                        "hnsw:num_threads": 1,
+                        **_HNSW_BLOAT_GUARD,
+                    },
+                    **ef_kwargs,
+                )
         else:
             collection = client.get_collection(collection_name, **ef_kwargs)
         _pin_hnsw_threads(collection)
diff --git a/tests/test_backends.py b/tests/test_backends.py
index b48b69f..5efa71b 100644
--- a/tests/test_backends.py
+++ b/tests/test_backends.py
@@ -372,6 +372,32 @@ def test_chroma_backend_create_collection_sets_hnsw_bloat_guard(tmp_path):
     assert col.metadata.get("hnsw:sync_threshold") == 50_000
 
 
+def test_get_collection_create_true_is_idempotent(tmp_path):
+    """Calling get_collection(create=True) twice on the same name must not crash.
+
+    ChromaDB 1.5.x's Rust bindings SIGSEGV when get_or_create_collection is
+    called with metadata that differs from the stored collection metadata. The
+    fix splits the call into get_collection -> fallback create_collection so the
+    metadata-comparison codepath in chromadb_rust_bindings is never reached for
+    existing collections. Regression guard for issue #1089.
+    """
+    palace = str(tmp_path / "palace")
+    backend = ChromaBackend()
+    backend.get_collection(palace, collection_name="mempalace_drawers", create=True)
+    col2 = backend.get_collection(palace, collection_name="mempalace_drawers", create=True)
+    assert isinstance(col2, ChromaCollection)
+
+
+def test_get_collection_create_true_preserves_existing_metadata(tmp_path):
+    """Existing collection metadata is not overwritten when reopened with create=True."""
+    palace = str(tmp_path / "palace")
+    backend = ChromaBackend()
+    backend.get_collection(palace, collection_name="mempalace_drawers", create=True)
+    col = backend.get_collection(palace, collection_name="mempalace_drawers", create=True)
+    assert col._collection.metadata["hnsw:space"] == "cosine"
+    assert col._collection.metadata.get("hnsw:batch_size") == 50_000
+
+
 def test_fix_blob_seq_ids_converts_blobs_to_integers(tmp_path):
     """Simulate a ChromaDB 0.6.x database with BLOB seq_ids and verify repair."""
     db_path = tmp_path / "chroma.sqlite3"