🐛 useValidLang rule incorrectly rejects valid BCP 47 language tags that include script subtags, such as zh-Hans-CN #8117
Description
Environment information
CLI:
Version: 2.3.5
Color support: true
Platform:
CPU Architecture: aarch64
OS: macos
Environment:
BIOME_LOG_PATH: unset
BIOME_LOG_PREFIX_NAME: unset
BIOME_CONFIG_PATH: unset
BIOME_THREADS: unset
NO_COLOR: unset
TERM: xterm-256color
JS_RUNTIME_VERSION: v24.3.0
JS_RUNTIME_NAME: node
NODE_PACKAGE_MANAGER: bun/1.3.2
Biome Configuration:
Status: Loaded successfully
Path: biome.json
Formatter enabled: true
Linter enabled: true
Assist enabled: true
VCS enabled: true
Workspace:
Open Documents: 0
What happened?
The useValidLang rule incorrectly rejects valid BCP 47 language tags that include script subtags, such as zh-Hans-CN (Simplified Chinese as used in China).
Expected result
According to BCP 47 and IANA Language Subtag Registry, these tags should be valid:
<html lang="zh-Hans-CN" /> // ✅ Should be valid (Simplified Chinese, China)
<html lang="zh-Hant-TW" /> // ✅ Should be valid (Traditional Chinese, Taiwan)
<html lang="sr-Cyrl-RS" /> // ✅ Should be valid (Serbian, Cyrillic script, Serbia)
Valid BCP 47 Language Tag Format
BCP 47 language tags follow this structure:
language [-script] [-region] [-variant] [-extension] [-privateuse]
Root Cause
The current implementation in use_valid_lang.rs only supports the simple language-country format:
let mut split_value = attribute_text.split('-');
match (split_value.next(), split_value.next()) {
(Some(language), Some(country)) => {
// Validates as language-country only
if !is_valid_language(language) { /* ... */ }
else if !is_valid_country(country) { /* ... */ }
else if split_value.next().is_some() {
// Rejects any additional subtags
return Some(UseValidLangState {
invalid_kind: InvalidKind::Value,
});
}
}
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