Avoid trigger of useless rules consequences

guessit/rules/processors.py

@@ -34,7 +34,9 @@ def when(self, matches, context):
             for match in matches.ending(group.end - 1):
                 ending.append(match)
 
-        return starting, ending
+        if starting or ending:
+            return starting, ending
+        return False
 
     def then(self, matches, when_response, context):
         starting, ending = when_response

guessit/rules/properties/bit_rate.py

@@ -69,4 +69,6 @@ def when(self, matches, context):
                     else:
                         to_rename.append(match)
 
-        return to_rename, to_remove
+        if to_rename or to_remove:
+            return to_rename, to_remove
+        return False

guessit/rules/properties/episodes.py

@@ -438,7 +438,9 @@ def when(self, matches, context):
                 if to_append:
                     to_remove.extend(weak_dup_matches)
 
-        return to_remove, to_append
+        if to_remove or to_append:
+            return to_remove, to_append
+        return False
 
 
 class CountValidator(Rule):
@@ -464,7 +466,9 @@ def when(self, matches, context):
                     season_count.append(count)
             else:
                 to_remove.append(count)
-        return to_remove, episode_count, season_count
+        if to_remove or episode_count or season_count:
+            return to_remove, episode_count, season_count
+        return False
 
 
 class SeePatternRange(Rule):
@@ -499,7 +503,9 @@ def when(self, matches, context):
 
             to_remove.append(separator)
 
-        return to_remove, to_append
+        if to_remove or to_append:
+            return to_remove, to_append
+        return False
 
 
 class AbstractSeparatorRange(Rule):
@@ -555,7 +561,9 @@ def when(self, matches, context):
 
             previous_match = next_match
 
-        return to_remove, to_append
+        if to_remove or to_append:
+            return to_remove, to_append
+        return False
 
 
 class RenameToAbsoluteEpisode(Rule):
@@ -683,7 +691,9 @@ def when(self, matches, context):
                             pass
 
                     to_remove.extend(weaks)
-        return to_remove, to_append
+        if to_remove or to_append:
+            return to_remove, to_append
+        return False
 
 
 class RemoveWeakIfSxxExx(Rule):
@@ -897,4 +907,6 @@ def when(self, matches, context):
             markers.append(marker)
             discs.extend(sorted(marker.initiator.children.named('episode'), key=lambda m: m.value))
 
-        return discs, markers, to_remove
+        if discs or markers or to_remove:
+            return discs, markers, to_remove
+        return False

guessit/rules/properties/language.py

@@ -390,7 +390,9 @@ def when(self, matches, context):
                 to_remove.extend(matches.conflicting(lang))
                 if prefix in to_remove:
                     to_remove.remove(prefix)
-        return to_rename, to_remove
+        if to_rename or to_remove:
+            return to_rename, to_remove
+        return False
 
     def then(self, matches, when_response, context):
         to_rename, to_remove = when_response
@@ -427,7 +429,9 @@ def when(self, matches, context):
                 to_append.append(lang)
                 if suffix in to_remove:
                     to_remove.remove(suffix)
-        return to_append, to_remove
+        if to_append or to_remove:
+            return to_append, to_remove
+        return False
 
     def then(self, matches, when_response, context):
         to_rename, to_remove = when_response

guessit/rules/properties/release_group.py

@@ -195,7 +195,8 @@ def when(self, matches, context):  # pylint:disable=inconsistent-return-statemen
 
                 if releasegroup.value:
                     to_append.append(releasegroup)
-                return to_remove, to_append
+                if to_remove or to_append:
+                    return to_remove, to_append
 
 
 class SceneReleaseGroup(Rule):
@@ -312,11 +313,11 @@ def when(self, matches, context):
 
         # If a release_group is found before, ignore this kind of release_group rule.
         if matches.named('release_group'):
-            return to_remove, to_append
+            return False
 
         if not matches.named('episode') and not matches.named('season') and matches.named('release_group'):
             # This doesn't seems to be an anime, and we already found another release_group.
-            return to_remove, to_append
+            return False
 
         for filepart in marker_sorted(matches.markers.named('path'), matches):
 
@@ -340,4 +341,7 @@ def when(self, matches, context):
                 to_append.append(group)
                 to_remove.extend(matches.range(empty_group.start, empty_group.end,
                                                lambda m: 'weak-language' in m.tags))
-        return to_remove, to_append
+
+        if to_remove or to_append:
+            return to_remove, to_append
+        return False

guessit/rules/properties/source.py

@@ -171,7 +171,9 @@ def when(self, matches, context):
                 to_remove.append(match)
                 to_append.append(new_source)
 
-        return to_remove, to_append
+        if to_remove or to_append:
+            return to_remove, to_append
+        return False
 
 
 class ValidateSource(Rule):

guessit/rules/properties/title.py

@@ -251,7 +251,7 @@ def when(self, matches, context):
         to_remove = []
 
         if matches.named(self.match_name, lambda match: 'expected' in match.tags):
-            return ret, to_remove
+            return False
 
         fileparts = [filepart for filepart in list(marker_sorted(matches.markers.named('path'), matches))
                      if not self.filepart_filter or self.filepart_filter(filepart, matches)]
@@ -284,7 +284,9 @@ def when(self, matches, context):
                 ret.extend(titles)
                 to_remove.extend(to_remove_c)
 
-        return ret, to_remove
+        if ret or to_remove:
+            return ret, to_remove
+        return False
 
 
 class TitleFromPosition(TitleBaseRule):