From 04cc62ea0669dbd9b93a2930f81bec14fe4cac77 Mon Sep 17 00:00:00 2001
From: Sven Geboers <geboers.sven@gmail.com>
Date: Thu, 30 Apr 2026 23:59:02 +0200
Subject: [PATCH] refactor: tighten exception handling in database.py and add
 BLE lint rule

- Wrap duckdb.connect() in try/except with specific duckdb.Error
- Replace bare  with  in _init_database
- Replace broad  with  for ALTER TABLE
- Add ruff BLE (blind except) lint rule to prevent regressions
- Add tests verifying graceful error handling for connect, insert, query

P2-002: Fix broad exception handling
---
 database.py                       | 20 +++++++++++-----
 pyproject.toml                    |  2 +-
 tests/test_database_exceptions.py | 38 +++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 7 deletions(-)
 create mode 100644 tests/test_database_exceptions.py

diff --git a/database.py b/database.py
index c0e346e..a9ee544 100644
--- a/database.py
+++ b/database.py
@@ -39,12 +39,17 @@ class MotionDatabase:
                         fh.write("[]")
             return
 
-        conn = duckdb.connect(self.db_path)
+        try:
+            conn = duckdb.connect(self.db_path)
+        except (duckdb.Error, OSError) as e:
+            _logger.warning("Could not connect to DuckDB at %s: %s. Operating in file mode.", self.db_path, e)
+            self._file_mode = True
+            return
 
         # Create sequence for auto-incrementing IDs
         try:
             conn.execute("CREATE SEQUENCE IF NOT EXISTS motions_id_seq START 1")
-        except:
+        except duckdb.Error:
             pass
 
         # Create tables with proper ID handling
@@ -72,7 +77,7 @@ class MotionDatabase:
                 "ALTER TABLE motions ADD COLUMN IF NOT EXISTS externe_identifier TEXT"
             )
             conn.execute("ALTER TABLE motions ADD COLUMN IF NOT EXISTS body_text TEXT")
-        except Exception:
+        except duckdb.Error:
             # Best-effort: if ALTER fails for any reason, continue without stopping app startup
             _logger.debug(
                 "Could not ALTER motions table to add new columns (may already exist or unsupported)."
@@ -188,7 +193,10 @@ class MotionDatabase:
             )
         """)
 
-        conn.close()
+        try:
+            conn.close()
+        except duckdb.Error:
+            pass
 
     def reset_database(self):
         """Development helper: drop known tables and re-run initialization.
@@ -201,7 +209,7 @@ class MotionDatabase:
             for t in ("party_results", "user_sessions", "motions"):
                 try:
                     conn.execute(f"DROP TABLE IF EXISTS {t}")
-                except Exception:
+                except duckdb.Error:
                     pass
             # Recreate schema
             conn.close()
@@ -209,7 +217,7 @@ class MotionDatabase:
         finally:
             try:
                 conn.close()
-            except Exception:
+            except duckdb.Error:
                 pass
 
     def append_audit_event(
diff --git a/pyproject.toml b/pyproject.toml
index bebd2c2..d1a2cc7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,7 +28,7 @@ dev = [
 ]
 
 [tool.ruff.lint]
-select = ["T20"]
+select = ["T20", "BLE"]
 ignore = []
 
 [tool.ruff.lint.per-file-ignores]
diff --git a/tests/test_database_exceptions.py b/tests/test_database_exceptions.py
new file mode 100644
index 0000000..a34e2ca
--- /dev/null
+++ b/tests/test_database_exceptions.py
@@ -0,0 +1,38 @@
+import logging
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from database import MotionDatabase
+
+
+class TestMotionDatabaseExceptionHandling:
+    @patch("database.duckdb")
+    def test_init_database_catches_duckdb_connect_errors(self, mock_duckdb, tmp_path):
+        mock_duckdb.Error = Exception
+        mock_duckdb.connect.side_effect = mock_duckdb.Error("db locked")
+        db = MotionDatabase(db_path=str(tmp_path / "test.db"))
+        assert db._file_mode is True
+
+    @patch("database.duckdb")
+    def test_insert_motion_catches_errors_and_returns_false(self, mock_duckdb, tmp_path):
+        mock_duckdb.Error = Exception
+        mock_conn = MagicMock()
+        mock_duckdb.connect.return_value = mock_conn
+
+        db = MotionDatabase(db_path=str(tmp_path / "test.db"))
+        # Now make insert_motion fail
+        mock_conn.execute.side_effect = mock_duckdb.Error("constraint violation")
+        result = db.insert_motion({"title": "Test", "date": "2024-01-01", "url": "http://test"})
+        assert result is False
+
+    @patch("database.duckdb")
+    def test_query_motions_catches_errors_and_returns_empty_list(self, mock_duckdb, tmp_path):
+        mock_duckdb.Error = Exception
+        mock_conn = MagicMock()
+        mock_duckdb.connect.return_value = mock_conn
+
+        db = MotionDatabase(db_path=str(tmp_path / "test.db"))
+        mock_conn.execute.side_effect = mock_duckdb.Error("syntax error")
+        result = db.get_filtered_motions()
+        assert result == []