Merge pull request #306 from ggozad/fix/read-only-inits-on-empty-folder

Prevent read-only mode from creating tables in empty directories

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 ## [Unreleased]
 
+### Fixed
+
+- **Read-only mode table creation**: `--read-only` no longer creates lance tables when pointed at an empty directory. `Store._init_tables()` now raises `ReadOnlyError` when tables are missing in read-only mode.
+
 ## [0.33.2] - 2026-03-11
 
 ### Changed

haiku_rag_slim/haiku/rag/cli.py

@@ -23,7 +23,10 @@ from haiku.rag.config import (  # noqa: E402
     set_config,
 )
 from haiku.rag.logging import configure_cli_logging  # noqa: E402
-from haiku.rag.store.exceptions import MigrationRequiredError  # noqa: E402
+from haiku.rag.store.exceptions import (  # noqa: E402
+    MigrationRequiredError,
+    ReadOnlyError,
+)
 from haiku.rag.utils import is_up_to_date  # noqa: E402
 
 _cli = typer.Typer(
@@ -34,7 +37,7 @@ _cli = typer.Typer(
 def cli():
     try:
         _cli()
-    except MigrationRequiredError as e:
+    except (MigrationRequiredError, ReadOnlyError) as e:
         typer.echo(f"Error: {e}", err=True)
         sys.exit(1)
 

haiku_rag_slim/haiku/rag/store/engine.py

@@ -333,10 +333,17 @@ class Store:
 
     def _init_tables(self):
         """Initialize database tables (create if they don't exist)."""
-        # Get list of existing tables
         existing_tables = self.db.table_names()
+        required_tables = {"documents", "chunks", "settings"}
+        missing_tables = required_tables - set(existing_tables)
 
-        # Create or get documents table
+        if missing_tables and self._read_only:
+            raise ReadOnlyError(
+                "Cannot create tables in read-only mode. "
+                "Use 'haiku-rag init' to create a new database."
+            )
+
+        # Create or open documents table
         if "documents" in existing_tables:
             self.documents_table = self.db.open_table("documents")
         else:
@@ -344,7 +351,7 @@ class Store:
                 "documents", schema=get_documents_arrow_schema()
             )
 
-        # Create or get chunks table
+        # Create or open chunks table
         if "chunks" in existing_tables:
             self.chunks_table = self.db.open_table("chunks")
         else:
@@ -354,7 +361,7 @@ class Store:
                 "content_fts", replace=True, with_position=True, remove_stop_words=False
             )
 
-        # Create or get settings table
+        # Create or open settings table
         if "settings" in existing_tables:
             self.settings_table = self.db.open_table("settings")
         else:

tests/store/test_read_only.py

@@ -28,6 +28,21 @@ class TestReadOnlyError:
 
 
 class TestStoreReadOnly:
+    def test_store_read_only_raises_on_empty_directory(self, tmp_path):
+        """Opening an empty directory in read-only mode raises ReadOnlyError."""
+        empty_dir = tmp_path / "empty_db"
+        empty_dir.mkdir()
+
+        with pytest.raises(
+            ReadOnlyError, match="Cannot create tables in read-only mode"
+        ):
+            Store(
+                empty_dir,
+                read_only=True,
+                skip_validation=True,
+                skip_migration_check=True,
+            )
+
     def test_store_default_is_not_read_only(self, temp_db_path):
         """Store defaults to not read-only."""
         store = Store(temp_db_path, create=True)