Fix absolute windows file urls with extra slash

For more context see d6f90be.

We however no longer implement the backslash to forward slash
conversion. There is no good reason for why Git does that conversion
and we do not need it to stay compatible (Git can handle both versions
just fine). Additionally, the logic for the conversion was very involved
and to implement it proper we would need to detect the shell we are
executing in (Git performs the conversion only in bash, not in cmd/ps).

Author: niklaswimmer

gix-url/src/parse/mod.rs

@@ -183,6 +183,14 @@ fn parse_file_url(input: &BStr, protocol_colon: usize) -> Result<crate::Url, Err
 
     // TODO: implement UNC path special case
     let windows_special_path = if cfg!(windows) {
+        // Inputs created via url::Url::from_file_path contain an additional `/` between the
+        // protocol and the absolute path. Make sure we ignore that first slash character to avoid
+        // producing invalid paths.
+        let input_after_protocol = if first_slash == 0 {
+            &input_after_protocol[1..]
+        } else {
+            input_after_protocol
+        };
         // parse `file://x:/path/to/git` as explained above
         if input_after_protocol.chars().nth(1) == Some(':') {
             Some(input_after_protocol)
@@ -226,7 +234,7 @@ fn parse_local(input: &BStr) -> Result<crate::Url, Error> {
         user: None,
         host: None,
         port: None,
-        path: input.into(),
+        path: input.to_owned(),
     })
 }
 

gix-url/tests/parse/file.rs

@@ -130,21 +130,6 @@ fn interior_relative_file_path_without_protocol() -> crate::Result {
     Ok(())
 }
 
-#[test]
-#[cfg(unix)]
-fn url_from_absolute_path() -> crate::Result {
-    assert_url(
-        url::Url::from_directory_path("/users/foo")
-            .expect("valid")
-            .to_file_path()
-            .expect("valid path")
-            .to_string_lossy()
-            .as_ref(),
-        url_alternate(Scheme::File, None, None, None, b"/users/foo/"),
-    )?;
-    Ok(())
-}
-
 #[test]
 fn url_from_relative_path_with_colon_in_name() -> crate::Result {
     let url = assert_url(
@@ -173,14 +158,8 @@ mod windows {
             url_alternate(Scheme::File, None, None, None, b"C:\\users\\1\\"),
         )?;
         // A special hack to support URLs on windows that are prefixed with `/` even though absolute.
-        assert_url(
-            "file:///c:/users/2",
-            url(Scheme::File, None, None, None, b"c:\\users\\2"),
-        )?;
-        assert_url(
-            "file:///c:/users/3/",
-            url(Scheme::File, None, None, None, b"c:\\users\\3\\"),
-        )?;
+        assert_url("file:///c:/users/2", url(Scheme::File, None, None, None, b"c:/users/2"))?;
+        assert_url("file:///c:/users/3", url(Scheme::File, None, None, None, b"c:/users/3"))?;
         Ok(())
     }
 
@@ -220,6 +199,20 @@ mod unix {
     use crate::parse::{assert_url, assert_url_roundtrip, url, url_alternate};
     use gix_url::Scheme;
 
+    #[test]
+    fn url_from_absolute_path() -> crate::Result {
+        assert_url(
+            url::Url::from_directory_path("/users/foo")
+                .expect("valid")
+                .to_file_path()
+                .expect("valid path")
+                .to_string_lossy()
+                .as_ref(),
+            url_alternate(Scheme::File, None, None, None, b"/users/foo/"),
+        )?;
+        Ok(())
+    }
+
     #[test]
     fn file_path_without_protocol() -> crate::Result {
         let url = assert_url(