enable backward compat for loading the best model

TTS/utils/arguments.py

@@ -86,24 +86,34 @@ def get_last_checkpoint(path):
     last_models = {}
     last_model_nums = {}
     for key in ['checkpoint', 'best_model']:
-        last_model_num = 0
+        last_model_num = None
         last_model = None
+        # pass all the checkpoint files and find
+        # the one with the largest model number suffix.
         for file_name in file_names:
-            try:
-                model_num = int(re.search(
-                    f"{key}_([0-9]+)", file_name).groups()[0])
-                if model_num > last_model_num:
+            match = re.search(f"{key}_([0-9]+)", file_name)
+            if match is not None:
+                model_num = int(match.groups()[0])
+                if model_num > last_model_num or last_model_num is None:
                     last_model_num = model_num
                     last_model = file_name
-            except AttributeError:  # if there's no match in the filename
-                continue
-        last_models[key] = last_model
-        last_model_nums[key] = last_model_num
+
+        # if there is not checkpoint found above
+        # find the checkpoint with the latest
+        # modification date.
+        key_file_names = [fn for fn in file_names if key in fn]
+        if last_model is None and len(key_file_names) > 0:
+            last_model = max(key_file_names, key=os.path.getctime)
+            last_model_num = os.path.getctime(last_model)
+
+        if last_model is not None:
+            last_models[key] = last_model
+            last_model_nums[key] = last_model_num
 
     # check what models were found
     if not last_models:
         raise ValueError(f"No models found in continue path {path}!")
-    elif 'checkpoint' not in last_models:  # no checkpoint just best model
+    if 'checkpoint' not in last_models:  # no checkpoint just best model
         last_models['checkpoint'] = last_models['best_model']
     elif 'best_model' not in last_models:  # no best model
         # this shouldn't happen, but let's handle it just in case