attempt ancestor canonicalization in get_normalized_path

helix-core/src/path.rs

@@ -40,6 +40,24 @@ pub fn expand_tilde(path: &Path) -> PathBuf {
 /// needs to improve on.
 /// Copied from cargo: <https://github.com/rust-lang/cargo/blob/070e459c2d8b79c5b2ac5218064e7603329c92ae/crates/cargo-util/src/paths.rs#L81>
 pub fn get_normalized_path(path: &Path) -> PathBuf {
+    // normalization strategy is to canonicalize first ancestor path that exists (i.e., canonicalize as much as possible),
+    // then run handrolled normalization on the non-existent remainder
+    let (base, path) = path
+        .ancestors()
+        .find(|path| path.exists())
+        .and_then(|path| Some((path, dunce::canonicalize(path).ok()?)))
+        .map(|(base, canonicalized)| {
+            (
+                canonicalized,
+                path.strip_prefix(base).unwrap(/* base is an ancestor of path */).into(),
+            )
+        })
+        .unwrap_or_else(|| (PathBuf::new(), PathBuf::from(path)));
+
+    if path.as_os_str().is_empty() {
+        return base;
+    }
+
     let mut components = path.components().peekable();
     let mut ret = if let Some(c @ Component::Prefix(..)) = components.peek().cloned() {
         components.next();
@@ -63,7 +81,7 @@ pub fn get_normalized_path(path: &Path) -> PathBuf {
             }
         }
     }
-    ret
+    base.join(ret)
 }
 
 /// Returns the canonical, absolute form of a path with all intermediate components normalized.
@@ -82,19 +100,13 @@ pub fn get_canonicalized_path(path: &Path) -> std::io::Result<PathBuf> {
 }
 
 pub fn get_relative_path(path: &Path) -> PathBuf {
-    let path = PathBuf::from(path);
     let path = if path.is_absolute() {
-        let cwdir = std::env::current_dir()
-            .and_then(dunce::canonicalize)
-            .expect("couldn't determine current directory");
-        dunce::canonicalize(&path)
-            .ok()
-            .and_then(|path| path.strip_prefix(cwdir).map(PathBuf::from).ok())
-            .unwrap_or(path)
+        let cwdir = std::env::current_dir().expect("couldn't determine current directory");
+        path.strip_prefix(cwdir).unwrap_or(path)
     } else {
         path
     };
-    fold_home_dir(&path)
+    fold_home_dir(path)
 }
 
 /// Returns a truncated filepath where the basepart of the path is reduced to the first