oops

allennlp/commands/train.py

@@ -179,7 +179,7 @@ def create_serialization_dir(params: Params, serialization_dir: str, recover: bo
         the directory doesn't exist, or doesn't match the configuration we're given.
     """
     if os.path.exists(serialization_dir) and os.listdir(serialization_dir):
-        if recover:
+        if not recover:
             raise ConfigurationError(f"Serialization directory ({serialization_dir}) already exists and is "
                                      f"not empty. Specify --recover to recover training from existing output.")
 

tests/commands/train_test.py

@@ -47,7 +47,7 @@ def test_train_model(self):
         os.makedirs(serialization_dir2)
         train_model(params(), serialization_dir=serialization_dir2)
 
-        # It's not OK if serialization dir exists and is non-empty:
+        # It's not OK if serialization dir exists and has junk in it non-empty:
         serialization_dir3 = os.path.join(self.TEST_DIR, 'non_empty_directory')
         assert not os.path.exists(serialization_dir3)
         os.makedirs(serialization_dir3)
@@ -57,6 +57,10 @@ def test_train_model(self):
         with pytest.raises(ConfigurationError):
             train_model(params(), serialization_dir=serialization_dir3)
 
+        # It's also not OK if serialization dir is a real serialization dir:
+        with pytest.raises(ConfigurationError):
+            train_model(params(), serialization_dir=os.path.join(self.TEST_DIR, 'test_train_model'))
+
     def test_train_with_test_set(self):
         params = Params({
                 "model": {