fix. Handle missing trailing slash for the Windows drive path.

url/src/lib.rs

@@ -3170,7 +3170,22 @@ fn file_url_segments_to_pathbuf_windows(
             estimated_capacity
         );
     }
+
+    // NOTE: when url got broken into segments, it loses the trailing slash `\`
+    // however, on windows, rust lang regards `c:\` as a valid absolute path rather than `c:`
+    // thus, this if-else add this '\' back for this ad-hoc case.
+    if string.len() == 2
+        && matches!(
+            string.chars().nth(0).map(|c| c.is_ascii_alphabetic()),
+            Some(true)
+        )
+        && matches!(string.chars().nth(1), Some(':'))
+    {
+        string.push('\\');
+    }
+
     let path = PathBuf::from(string);
+
     debug_assert!(
         path.is_absolute(),
         "to_file_path() failed to produce an absolute Path"

url/tests/unit.rs

@@ -541,6 +541,27 @@ fn append_empty_segment_then_mutate() {
     assert_eq!(url.to_string(), "http://localhost:6767/foo/bar?a=b");
 }
 
+#[test]
+#[cfg(feature = "std")]
+#[cfg(windows)]
+fn extend_empty_segment_to_win_driver() {
+    let path_str = r"C:\";
+    let prefix_path = PathBuf::from(r"C:\");
+    let prefix_path = std::fs::canonicalize(prefix_path).expect("Failed to canonicalize path");
+    let mut url = Url::from_file_path(prefix_path).expect("Failed to parse path");
+    let empty_segment: [&str; 0] = [];
+
+    url.path_segments_mut()
+        .expect("url path")
+        .pop_if_empty()
+        .extend(empty_segment);
+
+    let path = url
+        .to_file_path()
+        .expect("Failed to parse the windows driver path");
+    assert_eq!(path.to_str(), Some(path_str));
+}
+
 #[test]
 /// https://github.com/servo/rust-url/issues/243
 fn test_set_host() {