fix(rag): handle None metadata in get_all_indexed_paths and non-empty numpy in dim check

Two bugs in src/rag_engine.py were causing 'NoneType object has no attribute get'
in the live_gui RAG tests (test_rag_phase4_final_verify,
test_rag_phase4_stress):

1. _validate_collection_dim_result:148
   Old:  if not embeddings or len(embeddings) == 0:
   New:  if embeddings is None or len(embeddings) == 0:
   The 'if not embeddings' check raises ValueError('The truth value of an
   array with more than one element is ambiguous. Use a.any() or a.all()')
   when 'embeddings' is a non-empty numpy array (which is the normal case
   after documents are upserted). The exception is caught by the outer
   'except Exception' which returns a non-ok Result, causing __init__ to
   set self.collection = None. Subsequent 'get_all_indexed_paths()' then
   fails with 'NoneType has no attribute get' on self.collection.get().

2. get_all_indexed_paths:334
   Old:  return list(set(m.get('path') for m in res['metadatas'] if m.get('path')))
   New:  return list(set(m['path'] for m in res['metadatas'] if m is not None and m.get('path')))
   When chromadb returns 'metadatas=[None, ...]' (documents upserted
   without metadata), 'm.get('path')' fails with AttributeError on the
   first None element. Adds 'm is not None' guard.

Both fixes are defensive: the conditions that trigger them (orphan docs
without metadata, non-empty embeddings arrays) are normal valid
states that the old code couldn't handle.

New file: tests/test_rag_sync_none_error.py
   3 unit tests covering both bugs:
   - test_dim_check_does_not_raise_on_non_empty_ndarray
   - test_get_all_indexed_paths_handles_none_metadata
   - test_get_all_indexed_paths_returns_paths_with_metadata

Verified:
- 3/3 focused tests pass
- test_rag_phase4_final_verify.py::test_phase4_final_verify PASSES (was failing)
- test_rag_phase4_stress.py::test_rag_large_codebase_verification_sim PASSES (was failing)
- test_rag_visual_sim.py::test_rag_full_lifecycle_sim PASSES (still passing)

src/rag_engine.py

@@ -147,7 +147,7 @@ class RAGEngine:
    if not res:
     return Result(data=None)
    embeddings = res.get("embeddings") if isinstance(res, dict) else None
-   if not embeddings or len(embeddings) == 0:
+   if embeddings is None or len(embeddings) == 0:
     return Result(data=None)
    existing_dim = len(embeddings[0])
    expected_dim = len(self.embedding_provider.embed(["__rag_dim_check__"])[0])
@@ -331,7 +331,7 @@ class RAGEngine:
   res = self.collection.get(include=["metadatas"])
   if not res or not res["metadatas"]:
    return []
-  return list(set(m.get("path") for m in res["metadatas"] if m.get("path")))
+  return list(set(m["path"] for m in res["metadatas"] if m is not None and m.get("path")))
 
  def delete_documents_by_path(self, file_paths: List[str]):
   if not self.config.enabled or self.collection == "mock":

tests/test_rag_sync_none_error.py

@@ -0,0 +1,81 @@
+from __future__ import annotations
+import os
+import shutil
+import tempfile
+import pytest
+
+from src.rag_engine import RAGEngine
+from src.models import RAGConfig, VectorStoreConfig
+
+
+LOCAL_EMBED_DIM = 384
+
+
+@pytest.fixture
+def temp_workspace():
+ tmp = tempfile.mkdtemp()
+ try:
+  yield tmp
+ finally:
+  for _ in range(5):
+   try:
+    shutil.rmtree(tmp, ignore_errors=False)
+    break
+   except (OSError, PermissionError):
+    import time
+    time.sleep(0.2)
+  else:
+   shutil.rmtree(tmp, ignore_errors=True)
+
+
+def _make_chroma_collection_with_orphan_no_metadata(db_path, collection_name, dim=LOCAL_EMBED_DIM):
+ from src.rag_engine import _get_chromadb
+ chromadb_module, _ = _get_chromadb()
+ client = chromadb_module.PersistentClient(path=db_path)
+ col = client.get_or_create_collection(name=collection_name)
+ emb = [[0.01 * i for i in range(dim)]]
+ col.upsert(ids=["orphan"], embeddings=emb, documents=["orphan doc"])
+ return client, col
+
+
+def _build_engine(workspace, collection_name):
+ cfg = RAGConfig(
+  enabled=True,
+  embedding_provider="local",
+  vector_store=VectorStoreConfig(provider="chroma", collection_name=collection_name),
+ )
+ return RAGEngine(cfg, workspace)
+
+
+def test_dim_check_does_not_raise_on_non_empty_ndarray(temp_workspace):
+ db_path = os.path.abspath(os.path.join(temp_workspace, ".slop_cache", "chroma_test_dim"))
+ os.makedirs(db_path, exist_ok=True)
+ _make_chroma_collection_with_orphan_no_metadata(db_path, "test_dim")
+
+ engine = _build_engine(temp_workspace, "test_dim")
+ assert engine.collection is not None
+
+
+def test_get_all_indexed_paths_handles_none_metadata(temp_workspace):
+ db_path = os.path.abspath(os.path.join(temp_workspace, ".slop_cache", "chroma_test_orphan"))
+ os.makedirs(db_path, exist_ok=True)
+ _make_chroma_collection_with_orphan_no_metadata(db_path, "test_orphan")
+
+ engine = _build_engine(temp_workspace, "test_orphan")
+ paths = engine.get_all_indexed_paths()
+ assert paths == []
+
+
+def test_get_all_indexed_paths_returns_paths_with_metadata(temp_workspace):
+ db_path = os.path.abspath(os.path.join(temp_workspace, ".slop_cache", "chroma_test_with_meta"))
+ os.makedirs(db_path, exist_ok=True)
+ from src.rag_engine import _get_chromadb
+ chromadb_module, _ = _get_chromadb()
+ client = chromadb_module.PersistentClient(path=db_path)
+ col = client.get_or_create_collection(name="test_with_meta")
+ emb = [[0.01 * i for i in range(LOCAL_EMBED_DIM)]]
+ col.upsert(ids=["doc1"], embeddings=emb, documents=["doc1"], metadatas=[{"path": "f.txt", "chunk": 0}])
+
+ engine = _build_engine(temp_workspace, "test_with_meta")
+ paths = engine.get_all_indexed_paths()
+ assert "f.txt" in paths