Fix zh-Hant locale fallback

Author: qaijuang

crates/edit/src/bin/edit/localization.rs

@@ -12,6 +12,14 @@ static mut S_LANG: LangId = LangId::en;
 pub fn init() {
     let scratch = scratch_arena(None);
     let langs = sys::preferred_languages(&scratch);
+    let lang = select_language(langs);
+
+    unsafe {
+        S_LANG = lang;
+    }
+}
+
+fn select_language<'a>(langs: impl IntoIterator<Item = &'a str>) -> LangId {
     let mut lang = LangId::en;
 
     'outer: for l in langs {
@@ -23,11 +31,30 @@ pub fn init() {
         }
     }
 
-    unsafe {
-        S_LANG = lang;
-    }
+    lang
 }
 
 pub fn loc(id: LocId) -> &'static str {
     TRANSLATIONS[unsafe { S_LANG as usize }][id as usize]
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn assert_lang(langs: &[&str], expected: LangId) {
+        assert!(select_language(langs.iter().copied()) == expected);
+    }
+
+    // Regression test for https://github.com/microsoft/edit/issues/832.
+    #[test]
+    fn chinese_region_aliases_select_expected_script() {
+        assert_lang(&["zh-CN.UTF-8"], LangId::zh_hans);
+        assert_lang(&["zh-SG.UTF-8"], LangId::zh_hans);
+        assert_lang(&["zh-TW.UTF-8"], LangId::zh_hant);
+        assert_lang(&["zh-HK.UTF-8"], LangId::zh_hant);
+        assert_lang(&["zh-MO.UTF-8"], LangId::zh_hant);
+        assert_lang(&["zh-Hant.UTF-8"], LangId::zh_hant);
+        assert_lang(&["zh"], LangId::zh_hans);
+    }
+}

i18n/edit.toml

@@ -15,6 +15,11 @@ __default__ = [
 
 [__alias__]
 sr = "sr-cyrl"
+zh-cn = "zh-hans"
+zh-hk = "zh-hant"
+zh-mo = "zh-hant"
+zh-sg = "zh-hans"
+zh-tw = "zh-hant"
 zh = "zh-hans"
 
 # The keyboard key