fix: resolve . and .. in terminal cd and prevent panic in path elide

`absolutize` now lexically normalizes paths so `cd ..` navigates to the
parent directory instead of appending `..` literally. Also guard against
`file_name()` returning `None` in `fmt_path_elide_ex`, which caused a
panic on paths containing unresolved `..` components.

Closes #402

src/utils/fmt.rs

@@ -67,8 +67,10 @@ pub fn fmt_path_elide_ex(p: &Path, width: usize, extra_len: usize) -> String {
             // If ancestors_len is bigger than 3, push '…' and parent too
             if ancestors_len > 3 {
                 elided_path.push("…");
-                if let Some(parent) = p.ancestors().nth(1) {
+                if let Some(parent) = p.ancestors().nth(1)
-                    elided_path.push(parent.file_name().unwrap());
+                    && let Some(name) = parent.file_name()
+                {
+                    elided_path.push(name);
                 }
             }
             // Push file_name

src/utils/path.rs

@@ -12,14 +12,34 @@ use std::path::{Component, Path, PathBuf};
 /// assert_eq!(absolutize(&Path::new("/home/omar"), &Path::new("/tmp/readme.txt")).as_path(), Path::new("/tmp/readme.txt"));
 /// ```
 pub fn absolutize(wrkdir: &Path, target: &Path) -> PathBuf {
-    match target.is_absolute() {
+    let raw = match target.is_absolute() {
         true => target.to_path_buf(),
         false => {
             let mut p: PathBuf = wrkdir.to_path_buf();
             p.push(target);
             p
         }
+    };
+    normalize(&raw)
+}
+
+/// Normalize a path by resolving `.` and `..` components lexically
+/// (without touching the filesystem).
+fn normalize(path: &Path) -> PathBuf {
+    let mut parts: Vec<Component> = Vec::new();
+    for component in path.components() {
+        match component {
+            Component::ParentDir => {
+                // Pop the last normal component; never pop past root
+                if let Some(Component::Normal(_)) = parts.last() {
+                    parts.pop();
                 }
+            }
+            Component::CurDir => {} // skip `.`
+            other => parts.push(other),
+        }
+    }
+    parts.iter().collect()
 }
 
 /// This function will get the difference from path `path` to `base`. Basically will remove `base` from `path`
@@ -99,6 +119,44 @@ mod test {
         );
     }
 
+    #[test]
+    fn absolutize_resolves_parent_dir() {
+        assert_eq!(
+            absolutize(Path::new("/home/omar"), Path::new("..")).as_path(),
+            Path::new("/home")
+        );
+        assert_eq!(
+            absolutize(Path::new("/home/omar"), Path::new("../docs")).as_path(),
+            Path::new("/home/docs")
+        );
+        assert_eq!(
+            absolutize(Path::new("/home"), Path::new("..")).as_path(),
+            Path::new("/")
+        );
+    }
+
+    #[test]
+    fn absolutize_resolves_current_dir() {
+        assert_eq!(
+            absolutize(Path::new("/home/omar"), Path::new(".")).as_path(),
+            Path::new("/home/omar")
+        );
+        assert_eq!(
+            absolutize(Path::new("/home/omar"), Path::new("./docs")).as_path(),
+            Path::new("/home/omar/docs")
+        );
+    }
+
+    #[test]
+    fn normalize_path() {
+        assert_eq!(normalize(Path::new("/a/b/../c")), Path::new("/a/c"));
+        assert_eq!(normalize(Path::new("/a/b/./c")), Path::new("/a/b/c"));
+        assert_eq!(normalize(Path::new("/a/b/c/../..")), Path::new("/a"));
+        assert_eq!(normalize(Path::new("/")), Path::new("/"));
+        // Parent beyond root stays at root
+        assert_eq!(normalize(Path::new("/..")), Path::new("/"));
+    }
+
     #[test]
     fn calc_diff_paths() {
         assert_eq!(