Apply normcase to line from easy-install.pth (#3451)

Thanks for the suggestion from
https://github.com/astral-sh/uv/pull/3415#discussion_r1591772942

Also it looks like you improved `egg-link` parsing in
e23c91f52e
so copying the changes over to the other parse site (happy to move this
to a helper too, if so lmk where to put it)

crates/distribution-types/src/installed.rs

@@ -142,9 +142,14 @@ impl InstalledDist {
             // https://setuptools.pypa.io/en/latest/deprecated/python_eggs.html#egg-links
             // https://github.com/pypa/pip/blob/946f95d17431f645da8e2e0bf4054a72db5be766/src/pip/_internal/metadata/importlib/_envs.py#L86-L108
             let contents = fs::read_to_string(path)?;
-            let target = if let Some(line) = contents.lines().find(|line| !line.is_empty()) {
-                PathBuf::from(line.trim())
-            } else {
+            let Some(target) = contents.lines().find_map(|line| {
+                let line = line.trim();
+                if line.is_empty() {
+                    None
+                } else {
+                    Some(PathBuf::from(line))
+                }
+            }) else {
                 warn!("Invalid `.egg-link` file: {path:?}");
                 return Ok(None);
             };

crates/install-wheel-rs/src/uninstall.rs

@@ -211,6 +211,14 @@ pub fn uninstall_egg(egg_info: &Path) -> Result<Uninstall, Error> {
     })
 }
 
+fn normcase(s: &str) -> String {
+    if cfg!(windows) {
+        s.replace('/', "\\").to_lowercase()
+    } else {
+        s.to_owned()
+    }
+}
+
 static EASY_INSTALL_PTH: Lazy<Mutex<i32>> = Lazy::new(Mutex::default);
 
 /// Uninstall the legacy editable represented by the `.egg-link` file.
@@ -233,6 +241,9 @@ pub fn uninstall_legacy_editable(egg_link: &Path) -> Result<Uninstall, Error> {
         })
         .ok_or_else(|| Error::InvalidEggLink(egg_link.to_path_buf()))?;
 
+    // This comes from `pkg_resources.normalize_path`
+    let target_line = normcase(target_line);
+
     match fs::remove_file(egg_link) {
         Ok(()) => {
             debug!("Removed file: {}", egg_link.display());

crates/uv/tests/pip_uninstall.rs

@@ -474,6 +474,14 @@ fn uninstall_egg_info() -> Result<()> {
     Ok(())
 }
 
+fn normcase(s: &str) -> String {
+    if cfg!(windows) {
+        s.replace('/', "\\").to_lowercase()
+    } else {
+        s.to_owned()
+    }
+}
+
 /// Uninstall a legacy editable package in a virtual environment.
 #[test]
 fn uninstall_legacy_editable() -> Result<()> {
@@ -502,7 +510,7 @@ Version: 0.22.0
 
     site_packages.child("easy-install.pth").write_str(&format!(
         "something\n{}\nanother thing\n",
-        target.path().to_str().unwrap()
+        normcase(target.path().to_str().unwrap())
     ))?;
 
     // Run `pip uninstall`.