Fix a fatal error in the commands to create and update an extension's…

… translations

betty/cli/commands/extension_new_translation.py

@@ -10,7 +10,7 @@
 from betty.cli.commands import command, parameter_callback, Command
 from betty.locale import translation
 from betty.locale.localizable import _
-from betty.locale.translation import assert_extension_assets_directory_path
+from betty.locale.translation import assert_extension_has_assets_directory_path
 from betty.plugin import ShorthandPluginBase
 from betty.project import extension
 
@@ -53,7 +53,7 @@ async def click_command(self) -> click.Command:
             "extension",
             required=True,
             callback=parameter_callback(
-                lambda extension_id: assert_extension_assets_directory_path(
+                lambda extension_id: assert_extension_has_assets_directory_path(
                     extension_id_to_type_map.get(extension_id)
                 )
             ),

betty/cli/commands/extension_update_translations.py

@@ -15,7 +15,7 @@
 from betty.cli.commands import command, Command, parameter_callback
 from betty.locale import translation
 from betty.locale.localizable import _
-from betty.locale.translation import assert_extension_assets_directory_path
+from betty.locale.translation import assert_extension_has_assets_directory_path
 from betty.plugin import ShorthandPluginBase
 from betty.project import extension
 
@@ -59,7 +59,7 @@ async def click_command(self) -> click.Command:
             "extension",
             required=True,
             callback=parameter_callback(
-                lambda extension_id: assert_extension_assets_directory_path(
+                lambda extension_id: assert_extension_has_assets_directory_path(
                     extension_id_to_type_mapping.get(extension_id)
                 )
             ),

betty/locale/translation.py

@@ -8,7 +8,7 @@
 from contextlib import redirect_stdout
 from io import StringIO
 from pathlib import Path
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, TypeVar
 
 from aiofiles.os import makedirs
 from aiofiles.ospath import exists
@@ -18,11 +18,14 @@
 from betty.locale import get_data
 from betty.locale.babel import run_babel
 from betty.locale.localizable import _
+from betty.project.extension import Extension
 
 if TYPE_CHECKING:
     from collections.abc import Iterable
     from betty.project import Project
-    from betty.project.extension import Extension
+
+
+ExtensionT = TypeVar("ExtensionT", bound=Extension)
 
 
 def assert_extension_assets_directory_path(extension: type[Extension]) -> Path:
@@ -39,6 +42,16 @@ def assert_extension_assets_directory_path(extension: type[Extension]) -> Path:
     return assets_directory_path
 
 
+def assert_extension_has_assets_directory_path(
+    extension: type[ExtensionT],
+) -> type[ExtensionT]:
+    """
+    Check that the given extension has an assets directory, and return it.
+    """
+    assert_extension_assets_directory_path(extension)
+    return extension
+
+
 async def new_extension_translation(locale: str, extension: type[Extension]) -> None:
     """
     Create a new translation for the given extension.

betty/tests/locale/test_translation.py

@@ -10,6 +10,7 @@
 from betty.locale.translation import (
     update_dev_translations,
     assert_extension_assets_directory_path,
+    assert_extension_has_assets_directory_path,
 )
 from betty.test_utils.locale import PotFileTestBase
 from betty.test_utils.project.extension import DummyExtension
@@ -35,6 +36,26 @@ def test_with_assets_directory(self) -> None:
         )
 
 
+class TestAssertExtensionHasAssetsDirectoryPath:
+    class _DummyExtensionWithAssetsDirectory(DummyExtension):
+        @override
+        @classmethod
+        def assets_directory_path(cls) -> Path | None:
+            return Path(__file__)
+
+    def test_without_assets_directory(self) -> None:
+        with pytest.raises(UserFacingError):
+            assert_extension_has_assets_directory_path(DummyExtension)
+
+    def test_with_assets_directory(self) -> None:
+        assert (
+            assert_extension_has_assets_directory_path(
+                self._DummyExtensionWithAssetsDirectory
+            )
+            == self._DummyExtensionWithAssetsDirectory
+        )
+
+
 class TestPotFile(PotFileTestBase):
     @override
     def assets_directory_path(self) -> Path: