GH-162: fix serialization issue for legacy models

flair/embeddings.py

@@ -462,13 +462,16 @@ def embedding_length(self) -> int:
 
     def _add_embeddings_internal(self, sentences: List[Sentence]) -> List[Sentence]:
 
-        cache_path = '{}-tmp-cache.sqllite'.format(self.name) if self.cache_directory is None else os.path.join(
-            self.cache_directory, '{}-tmp-cache.sqllite'.format(os.path.basename(self.name)))
-
-        # by default, use_cache is false (for older pre-trained models TODO: remove in version 0.4)
-        if 'cache' not in self.__dict__ or 'cache_directory' not in self.__dict__ or not os.path.exists(cache_path):
+        # this whole block is for compatibility with older serialized models  TODO: remove in version 0.4
+        if 'cache' not in self.__dict__ or 'cache_directory' not in self.__dict__:
             self.use_cache = False
             self.cache_directory = None
+        else:
+            cache_path = '{}-tmp-cache.sqllite'.format(self.name) if not self.cache_directory else os.path.join(
+                self.cache_directory, '{}-tmp-cache.sqllite'.format(os.path.basename(self.name)))
+            if not os.path.exists(cache_path):
+                self.use_cache = False
+                self.cache_directory = None
 
         # if cache is used, try setting embeddings from cache first
         if self.use_cache: