Always fallback to the DEFAULT_MODEL_FAMILY

The code attempted to fallback to this, but if no model_path was given
then we were not actually falling back to
DEFAULT_MODEL_FAMILY (merlinite). This ensures we always fallback to
it, even if no model_path is given.

Signed-off-by: Ben Browning <bbrownin@redhat.com>

Author: bbrowning

src/instructlab/sdg/utils/models.py

@@ -22,5 +22,10 @@ def get_model_family(model_family, model_path):
         return model_family
 
     # Try to guess the model family based on the model's filename
-    guess = re.match(r"^\w*", os.path.basename(model_path)).group(0).lower()
-    return guess if guess in registry else DEFAULT_MODEL_FAMILY
+    if model_path:
+        guess = re.match(r"^\w*", os.path.basename(model_path)).group(0).lower()
+        if guess in registry:
+            return guess
+
+    # Nothing was found, so just return the default
+    return DEFAULT_MODEL_FAMILY

tests/test_models.py

@@ -64,3 +64,8 @@ def test_unknown_model_family(self):
                 "foobar", "./models/mixtral-8x7b-instruct-v0.1.Q4_K_M.gguf"
             )
         assert "Unknown model family: foobar" in str(exc.value)
+
+    def test_none_args(self):
+        assert (
+            models.get_model_family(None, None) == "merlinite"
+        )