feat(add-ons): improved LINGUAS detection

Gracefully handle situation when POT file is placed differently than PO
and LINGUAS files.

Author: nijel

docs/changes.rst

@@ -10,6 +10,7 @@ Weblate 2026.7
 * Management interface access control is now more fine-grained with dedicated site-wide permissions.
 * Default commit and merge request message templates now use Conventional Commits, and settings forms can restore installation defaults for individual message templates.
 * Documented :ref:`legal` customizations and added options to hide legal pages or disable document numbering.
+* :ref:`addon-weblate.gettext.linguas` better detects ``LINGUAS`` file presence.
 
 .. rubric:: Bug fixes
 

weblate/addons/gettext.py

@@ -61,7 +61,7 @@
 )
 POT_BLANK_COPYRIGHT_RE = re.compile(r"^# Copyright \(C\)(?: [0-9– -]*)?$")
 if TYPE_CHECKING:
-    from collections.abc import Callable, Generator
+    from collections.abc import Callable, Generator, Iterator
 
     from weblate.addons.base import CompatDict
     from weblate.formats.ttkit import PoFormat
@@ -139,22 +139,28 @@ class UpdateLinguasAddon(GettextBaseAddon):
     )
 
     @staticmethod
-    def get_linguas_path(component: Component) -> str:
-        base = component.get_new_base_filename()
-        if not base:
-            base = os.path.join(
-                component.full_path, component.filemask.replace("*", "x")
-            )
-        return os.path.join(os.path.dirname(base), "LINGUAS")
+    def get_linguas_paths(component: Component) -> Iterator[str]:
+        # First look at the POT file location
+        try:
+            base = component.get_new_base_filename()
+        except ValidationError:
+            base = None
+        if base:
+            yield os.path.join(os.path.dirname(base), "LINGUAS")
+        # Fallback to PO file location
+        base = os.path.join(component.full_path, component.filemask.replace("*", "x"))
+        yield os.path.join(os.path.dirname(base), "LINGUAS")
 
     @classmethod
     def get_validated_linguas_path(cls, component: Component) -> str | None:
-        try:
-            path = cls.get_linguas_path(component)
-            component.check_file_is_valid(path)
-        except ValidationError:
-            return None
-        return path
+        for path in cls.get_linguas_paths(component):
+            try:
+                component.check_file_is_valid(path)
+            except ValidationError:
+                continue
+            if os.path.exists(path):
+                return path
+        return None
 
     @classmethod
     def can_install(
@@ -171,7 +177,7 @@ def can_install(
         if component is None:
             return True
         path = cls.get_validated_linguas_path(component)
-        return path is not None and os.path.exists(path)
+        return path is not None
 
     @staticmethod
     def update_linguas(lines: list[str], codes: set[str]) -> tuple[bool, list[str]]:

weblate/addons/tests.py

@@ -936,6 +936,24 @@ def test_update_linguas(self) -> None:
         self.assertIn("LINGUAS", commit)
         self.assertIn("\n+cs de it", commit)
 
+    def test_update_linguas_uses_po_path_when_new_base_elsewhere(self) -> None:
+        translation = self.get_translation()
+        pot_path = Path(self.component.full_path) / "pot" / "hello.pot"
+        pot_path.parent.mkdir()
+        source_path = cast("str", self.component.get_new_base_filename())
+        shutil.copy(source_path, pot_path)
+        self.component.new_base = "pot/hello.pot"
+        self.component.save(update_fields=["new_base"])
+
+        self.assertTrue(UpdateLinguasAddon.can_install(component=self.component))
+        addon = UpdateLinguasAddon.create(component=self.component)
+        commit = self.component.repository.show(self.component.repository.last_revision)
+        self.assertIn("po/LINGUAS", commit)
+        self.assertIn("\n+cs\n", commit)
+
+        addon.post_add(translation)
+        self.assertEqual(translation.addon_commit_files, [])
+
     def test_update_linguas_rejects_symlink(self) -> None:
         translation = self.get_translation()
         addon = UpdateLinguasAddon.create(component=translation.component)
@@ -960,7 +978,7 @@ def test_update_linguas_rejects_symlink(self) -> None:
             Path(handle.name).read_text(encoding="utf-8"), "outside repository\n"
         )
 
-    def test_update_linguas_invalid_new_base_returns_false(self) -> None:
+    def test_update_linguas_invalid_new_base_uses_po_path(self) -> None:
         translation = self.get_translation()
         addon = UpdateLinguasAddon.create(component=self.component)
 
@@ -972,7 +990,12 @@ def test_update_linguas_invalid_new_base_returns_false(self) -> None:
         os.unlink(new_base_path)
         os.symlink(handle.name, new_base_path)
 
-        self.assertFalse(UpdateLinguasAddon.can_install(component=self.component))
+        linguas_path = os.path.join(self.component.full_path, "po", "LINGUAS")
+        self.assertEqual(
+            UpdateLinguasAddon.get_validated_linguas_path(self.component),
+            linguas_path,
+        )
+        self.assertTrue(UpdateLinguasAddon.can_install(component=self.component))
         addon.post_add(translation)
         self.assertEqual(translation.addon_commit_files, [])