fix: add error logging for failed detectors and update regex to return None for empty patterns

Author: saichandrapandraju

garak/detectors/function.py

@@ -142,6 +142,10 @@ def detect(self, attempt: garak.attempt.Attempt) -> List[float]:
         """
         # If detection_function failed to load, return None for all outputs
         if self.detection_function is None:
+            logging.error(
+                "function.FunctionDetector: Failed to load function %s",
+                self.function_name
+            )
             return [None] * len(attempt.outputs)
 
         results = []

garak/detectors/regex.py

@@ -145,14 +145,16 @@ def detect(self, attempt: garak.attempt.Attempt) -> List[float]:
             List of scores (0.0 or 1.0) for each output
         """
         results = [None] * len(attempt.outputs)
+        if not self.compiled_patterns:
+            logging.error(
+                "regex.RegexDetector: No compiled patterns found, returning None for all outputs"
+            )
+            return results
+        
         for idx, output in enumerate(attempt.outputs):
             output_text = output.text if output else None
             if output_text is None:
                 continue
-            
-            if not self.compiled_patterns:
-                results[idx] = 0.0  # default to safe if no patterns are provided
-                continue
 
             # Check patterns based on match_type
             matched = False

tests/detectors/test_detectors_regex.py

@@ -159,7 +159,7 @@ def test_none_output_handling(self):
         assert results[2] == 0.0
 
     def test_empty_patterns_returns_safe(self):
-        """Test that RegexDetector with no patterns returns 0.0 (safe)"""
+        """Test that RegexDetector with no patterns returns None"""
         config = {
                 'detectors': {
                     'regex': {
@@ -176,7 +176,7 @@ def test_empty_patterns_returns_safe(self):
         attempt.outputs = [garak.attempt.Message("any text here")]
 
         results = detector.detect(attempt)
-        assert results[0] == 0.0  # Safe with no patterns
+        assert results[0] is None  # None with no patterns
 
     def test_multiline_flag(self):
         """Test MULTILINE flag for matching at line boundaries"""
@@ -442,7 +442,7 @@ def test_single_string_re_flags_normalized(self):
         assert 'MULTILINE' in detector.re_flags
 
     def test_all_invalid_patterns_returns_safe(self):
-        """Test that if all patterns are invalid, detector returns 0.0 (safe)"""
+        """Test that if all patterns are invalid, detector returns None"""
         config = {
                 'detectors': {
                     'regex': {
@@ -459,9 +459,9 @@ def test_all_invalid_patterns_returns_safe(self):
         # No valid patterns compiled
         assert len(detector.compiled_patterns) == 0
 
-        # Should return safe (0.0)
+        # Should return None
         attempt = garak.attempt.Attempt(prompt=garak.attempt.Message())
         attempt.outputs = [garak.attempt.Message("any text")]
 
         results = detector.detect(attempt)
-        assert results[0] == 0.0  # Safe when no valid patterns
+        assert results[0] is None  # None when no valid patterns