Add an explicit call to merge_wtih_defaults() when loading a config f…

…rom a model directory. (#2226)

* Add call to merge_wtih_defaults in api.py.

* Add a test that loads an old model (from S3) and uses it to run prediction.

* Use zipped file + wget to load old Ludwig model from a zipped file, hosted on S3.

ludwig/api.py

@@ -1369,6 +1369,9 @@ def load(
 
         config = backend.broadcast_return(lambda: load_json(os.path.join(model_dir, MODEL_HYPERPARAMETERS_FILE_NAME)))
 
+        # Upgrades deprecated fields and adds new required fields, in case the config loaded from disk is old.
+        config = merge_with_defaults(config)
+
         if backend_param is None and "backend" in config:
             # Reset backend from config
             backend = initialize_backend(config.get("backend"))

requirements_test.txt

@@ -1,5 +1,6 @@
 pytest
 pytest-timeout
+wget
 six>=1.13.0
 aim
 wandb<0.12.11

tests/regression_tests/model/test_old_models.py

@@ -0,0 +1,34 @@
+import os
+import zipfile
+
+import pandas as pd
+import wget
+
+from ludwig.api import LudwigModel
+
+
+def test_model_loaded_from_old_config_prediction_works(tmpdir):
+    # Titanic model based on 0.5.3.
+    old_model_url = "https://predibase-public-us-west-2.s3.us-west-2.amazonaws.com/ludwig_unit_tests/old_model.zip"
+    old_model_filename = wget.download(old_model_url, tmpdir)
+    with zipfile.ZipFile(old_model_filename, "r") as zip_ref:
+        zip_ref.extractall(tmpdir)
+    example_data = {
+        "PassengerId": 892,
+        "Pclass": 3,
+        "Name": "Kelly, Mr. James",
+        "Sex": "male",
+        "Age": 34.5,
+        "SibSp": 0,
+        "Parch": 0,
+        "Ticket": "330911",
+        "Fare": 7.8292,
+        "Cabin": None,
+        "Embarked": "Q",
+    }
+    test_set = pd.DataFrame(example_data, index=[0])
+
+    ludwig_model = LudwigModel.load(os.path.join(tmpdir, "old_model/model"))
+    predictions, _ = ludwig_model.predict(dataset=test_set)
+
+    assert predictions.to_dict()["Survived_predictions"] == {0: False}