Fix translation fall backs thanks @lache

Author: jmbrunskill

server/service/src/localisations.rs

@@ -76,15 +76,22 @@ impl Localisations {
         let default_namespace = "common".to_string();
         let default_language = "en".to_string();
 
-        let language = language.to_string();
+        let language_with_dialect = language.to_string();
+        // e.g. if language is "en-GB" then base_language is "en"
+        let base_language = language.split('-').next().unwrap_or(language).to_string();
+
         let namespace = namespace.unwrap_or(default_namespace.clone());
 
         // make cascading array of fallback options:
         for (language, namespace, key) in [
             // first look for key in nominated namespace
-            (&language, &namespace, &key),
+            (&language_with_dialect, &namespace, &key),
             // then look for key in common.json
-            (&language, &default_namespace, &key),
+            (&language_with_dialect, &default_namespace, &key),
+            // then look for key in nominated namespace in base lang
+            (&base_language, &namespace, &key),
+            // then look for key in common.json in base lang
+            (&base_language, &default_namespace, &key),
             // then look for key in nominated namespace in en
             (&default_language, &namespace, &key),
             // then look for key in common.json in en
@@ -182,13 +189,22 @@ mod test {
         };
         let translated_value = localisations.get_translation(args, lang).unwrap();
         assert_eq!("fallback wrong key", translated_value);
+        // // test missing translation in dialect falls back to base language
+        let args = GetTranslation {
+            namespace: Some("common".to_string()),
+            fallback: Some("fallback".to_string()),
+            key: "button.close".to_string(),
+        };
+        let lang = "fr-MISSING_DIALECT";
+        let translated_value = localisations.get_translation(args, lang).unwrap();
+        assert_eq!("Fermer", translated_value);
         // // test wrong language dir falls back to english translation
         let args = GetTranslation {
             namespace: Some("common".to_string()),
             fallback: Some("fallback wrong key".to_string()),
             key: "button.close".to_string(),
         };
-        let lang = "fr-non-existent-lang";
+        let lang = "non_existent_lang";
         let translated_value = localisations.get_translation(args, lang).unwrap();
         assert_eq!("Close", translated_value);
         // test no translation in namespace falls back to common.json namespace