feat(alerts): add monolingual glossary alert

Things will not work as expected in this setup, so be clear in this.

See #11520

docs/changes.rst

@@ -7,6 +7,7 @@ Released on May 9th 2024.
 
 * Visually highlight explanation in :ref:`glossary`.
 * Add :ref:`addons` history tab in management.
+* New :ref:`alerts` when :ref:`glossary` might not work as expected.
 
 **Bug fixes**
 

weblate/templates/trans/alert/monolingualglossary.html

@@ -0,0 +1,6 @@
+{% load i18n %}
+{% load translations %}
+
+<p>{% trans "Using monolingual files as a glossary is not recommended because adding strings to target language only is not possible in monolingual files." %}</p>
+
+<p>{% trans "You can continue using the glossary this way, but some features will be unavailable." %}</p>

weblate/trans/models/alert.py

@@ -657,3 +657,14 @@ def check_component(component: Component) -> bool | None | dict:
         oldest_change = component.change_set.order_by("timestamp").first()
         # Weird, each component should have change
         return oldest_change is None or oldest_change.timestamp < cutoff
+
+
+@register
+class MonolingualGlossary(BaseAlert):
+    verbose = gettext_lazy("Glossary using monolingual files.")
+    doc_page = "user/glossary"
+    dismissable = True
+
+    @staticmethod
+    def check_component(component: Component) -> bool | None | dict:
+        return component.is_glossary and bool(component.template)