use a constant for the lang config filename

Author: kirawi

book/src/languages.md

@@ -14,4 +14,4 @@ auto-format = false
 
 # Project-level Configuration
 
-You can create a `.helix` directory either in the current working directory or in the same directory as `.git`. Then you can write a `languages.toml` file that will overwrite both global and default language settings.
+You can create a `.helix` folder containing a `languages.toml` folder in either the CWD or root directory. If `.helix` exists in both folders, the CWD config will override the root config. The local config overrides both global and default language settings.

helix-core/src/lib.rs

@@ -95,9 +95,8 @@ pub fn config_dir() -> std::path::PathBuf {
     path
 }
 
-/// First looks for the local `.helix` directory in CWD. If it can't find it, then
-/// it searches for it within the root `.git` directory. Otherwise, it uses the CWD
-/// to avoid an unwrap.
+/// Looks for the `.helix` config directory in the root directory, or otherwise in the
+/// current working directory.
 pub fn local_config_dir() -> std::path::PathBuf {
     let root = find_root(None)
         .unwrap_or_else(|| std::env::current_dir().expect("unable to determine current directory"));

helix-term/src/application.rs

@@ -92,15 +92,18 @@ impl Application {
             Err(err) => return Err(Error::new(err)),
         };
 
+        const LANG_CONFIG_FILENAME: &str = "languages.toml";
+
         // Config override order: local (cwd) -> local (root) -> global -> default.
         // Read and parse the `languages.toml` files as TOML objects.
         let default_lang_config: toml::Value =
-            toml::from_slice(include_bytes!("../../languages.toml"))
-                .expect("failed to read the default `languages.toml`");
+            toml::from_slice(include_bytes!("../../languages.toml")).unwrap_or_else(|_| {
+                panic!("failed to read the default `{}`", LANG_CONFIG_FILENAME)
+            });
         let lang_config: toml::Value = {
-            let local_cwd_config = load_lang_config(cwd.join(".helix/languages.toml"))?;
-            let local_root_config = load_lang_config(local_config_dir.join("languages.toml"))?;
-            let global_config = load_lang_config(config_dir.join("languages.toml"))?;
+            let local_cwd_config = load_lang_config(cwd.join(".helix").join(LANG_CONFIG_FILENAME))?;
+            let local_root_config = load_lang_config(local_config_dir.join(LANG_CONFIG_FILENAME))?;
+            let global_config = load_lang_config(config_dir.join(LANG_CONFIG_FILENAME))?;
             [
                 local_root_config,
                 global_config,
@@ -113,7 +116,7 @@ impl Application {
         // Convert previous `toml::Value`s into the config type.
         let default_syn_loader_config: helix_core::syntax::Configuration = default_lang_config
             .try_into()
-            .expect("failed to parse the default `languages.toml`");
+            .unwrap_or_else(|_| panic!("failed to parse the default `{}`", LANG_CONFIG_FILENAME));
         let syn_loader_config: helix_core::syntax::Configuration =
             lang_config.try_into().unwrap_or_else(|err| {
                 eprintln!("Bad language config: {}", err);