fixed #146: stopped panicking on multi-byte chars in config paths

* fix: avoid panic on multi-byte chars in config group names

to_target_path sliced the path component at byte index 1, which panics
when the first character is multi-byte (e.g. a folder named Übersicht).
Iterate chars instead of slicing bytes.

* fixed unit test for unicode in dotfile paths

---------

Co-authored-by: RaphGL <raphfl.dev@gmail.com>

Author: SAY-5

src/dotfiles.rs

@@ -275,12 +275,15 @@ impl Dotfile {
         while let Some(comp) = group_path_components.next() {
             let comp = comp.as_os_str().to_str().unwrap();
 
-            if comp.len() < 2 {
+            let mut comp_chars = comp.chars();
+            let Some(prefix) = comp_chars.next() else {
                 continue;
-            }
+            };
+            let comp = comp_chars.as_str();
 
-            let prefix = comp.chars().next().unwrap();
-            let comp = &comp[1..];
+            if comp.is_empty() {
+                continue;
+            }
 
             if prefix == '%' {
                 let Ok(comp) = env::var(comp) else {
@@ -345,7 +348,9 @@ pub fn get_potential_dotfiles_paths(profile: Option<String>) -> PotentialDotfile
     PotentialDotfilePaths {
         home: dirs::home_dir().unwrap().join(format!(".{dotfiles_dir}")),
         config: dirs::config_dir().unwrap().join(&dotfiles_dir),
-        env: std::env::var("TUCKR_HOME").map(|p| PathBuf::from(p).join(dotfiles_dir)).ok(),
+        env: std::env::var("TUCKR_HOME")
+            .map(|p| PathBuf::from(p).join(dotfiles_dir))
+            .ok(),
         test: std::env::temp_dir()
             .join(format!(
                 "tuckr-{}",
@@ -564,6 +569,27 @@ mod tests {
         );
     }
 
+    #[test]
+    fn dotfile_to_target_path_non_ascii_name() {
+        let stem = std::path::PathBuf::new()
+            .join(".config")
+            .join("übersicht")
+            .join("widgets")
+            .join("道具");
+
+        // Names with multi-byte characters must not panic on byte slicing.
+        let group = get_dotfiles_path(None)
+            .unwrap()
+            .join("Configs")
+            .join("übersicht")
+            .join(&stem);
+
+        assert_eq!(
+            Dotfile::try_from(group).unwrap().to_target_path().unwrap(),
+            super::get_dotfiles_target_dir_path().unwrap().join(stem)
+        );
+    }
+
     #[test]
     fn dotfile_targets_root() {
         let dotfiles_dir = super::get_dotfiles_path(None).unwrap().join("Configs");
@@ -672,9 +698,26 @@ mod tests {
         };
 
         let potential_paths = super::get_potential_dotfiles_paths(Some("whatever".into()));
-        assert_eq!(potential_paths.config.file_name().unwrap(), "dotfiles_whatever");
-        assert_eq!(potential_paths.home.file_name().unwrap(), ".dotfiles_whatever");
-        assert_eq!(potential_paths.env.unwrap().file_name().unwrap(), "dotfiles_whatever");
-        assert!(potential_paths.test.file_name().unwrap().to_str().unwrap().starts_with("dotfiles"));
+        assert_eq!(
+            potential_paths.config.file_name().unwrap(),
+            "dotfiles_whatever"
+        );
+        assert_eq!(
+            potential_paths.home.file_name().unwrap(),
+            ".dotfiles_whatever"
+        );
+        assert_eq!(
+            potential_paths.env.unwrap().file_name().unwrap(),
+            "dotfiles_whatever"
+        );
+        assert!(
+            potential_paths
+                .test
+                .file_name()
+                .unwrap()
+                .to_str()
+                .unwrap()
+                .starts_with("dotfiles")
+        );
     }
 }