variable/function collision detection

src/ytdl_sub/config/overrides.py

@@ -76,7 +76,6 @@ class Overrides(DictFormatterValidator, Scriptable):
                     " built-in ytdl-sub function name."
                 )
 
-
         self.unresolvable.add(VARIABLES.entry_metadata.variable_name)
 
     def initial_variables(

src/ytdl_sub/config/validators/variable_validation.py

@@ -88,6 +88,15 @@ class VariableValidation:
             resolved_variables=self.resolved_variables,
         )
 
+        for added_variable in added_variables:
+            if added_variable in overrides.keys:
+                # pylint: disable=protected-access
+                raise overrides._validation_exception(
+                    f"Override variable with name {added_variable} cannot be used since it is a"
+                    " built-in ytdl-sub variable added by a plugin."
+                )
+                # pylint: enable=protected-access
+
         # Set unresolved as variables that are added but do not exist as entry/override variables
         # Then update resolved variables to reflect that
         self.unresolved_variables = added_variables | modified_variables
@@ -113,15 +122,6 @@ class VariableValidation:
         ).get(plugin_op, set())
         modified_variables = options.modified_variables().get(plugin_op, set())
 
-        if added_variables:
-            for added_variable in added_variables:
-                if added_variable in self.resolved_variables:
-                    # pylint: disable=protected-access
-                    raise options._validation_exception(
-                        f"Tried added the variable '{added_variable}', but it already "
-                        f"exists as a defined variable."
-                    )
-
         resolved_variables = added_variables | modified_variables
 
         self.script.add(_add_dummy_variables(resolved_variables))

tests/unit/config/test_preset.py

@@ -260,13 +260,36 @@ class TestPreset:
                 },
             )
 
+    def test_preset_error_override_variable_collides_added_variable(
+        self, config_file, output_options, youtube_video
+    ):
+        with pytest.raises(
+            ValidationException,
+            match=re.escape(
+                f"Override variable with name subtitles_ext cannot be used since"
+                " it is a built-in ytdl-sub variable added by a plugin."
+            ),
+        ):
+            _ = Preset(
+                config=config_file,
+                name="test",
+                value={
+                    "download": youtube_video,
+                    "output_options": {"output_directory": "dir", "file_name": "ack"},
+                    "subtitles": {
+                        "embed_subtitles": True,
+                    },
+                    "overrides": {"subtitles_ext": "collide"},
+                },
+            )
+
     @pytest.mark.parametrize(
         "function_name",
         [
             "%extract_field_from_siblings",
             "%extract_field_from_metadata_array",
             "%sanitize",
-            "%array"
+            "%array",
         ],
     )
     def test_preset_error_override_variable_collides_with_custom_function(