try to fix windows (#301)

Author: Byron

git-worktree/src/index.rs

@@ -1,4 +1,5 @@
 use git_hash::oid;
+use std::io::ErrorKind::AlreadyExists;
 
 use crate::{index, index::checkout::Collision};
 
@@ -87,6 +88,7 @@ pub fn checkout<Find>(
 where
     Find: for<'a> FnMut(&oid, &'a mut Vec<u8>) -> Option<git_object::BlobRef<'a>>,
 {
+    use std::io::ErrorKind::AlreadyExists;
     let root = path.as_ref();
     let mut buf = Vec::new();
     let mut collisions = Vec::new();
@@ -100,9 +102,17 @@ where
         match res {
             Ok(()) => {}
             // TODO: use ::IsDirectory as well when stabilized instead of raw_os_error()
+            #[cfg(windows)]
             Err(index::checkout::Error::Io(err))
-                if err.kind() == std::io::ErrorKind::AlreadyExists || err.raw_os_error() == Some(21) =>
+                if err.kind() == AlreadyExists || err.kind() == std::io::ErrorKind::PermissionDenied =>
             {
+                collisions.push(Collision {
+                    path: entry_path.into(),
+                    error_kind: err.kind(),
+                });
+            }
+            #[cfg(not(windows))]
+            Err(index::checkout::Error::Io(err)) if err.kind() == AlreadyExists || err.raw_os_error() == Some(21) => {
                 // We are here because a file existed or was blocked by a directory which shouldn't be possible unless
                 // we are on a file insensitive file system.
                 collisions.push(Collision {

git-worktree/tests/index/mod.rs

@@ -83,25 +83,29 @@ mod checkout {
         let opts = opts_with_symlink(true);
         let (source_tree, destination, _index, outcome) =
             checkout_index_in_tmp_dir(opts, "make_ignorecase_collisions").unwrap();
+        #[cfg(windows)]
+        let error_kind = ErrorKind::PermissionDenied;
+        #[cfg(not(windows))]
+        let error_kind = ErrorKind::AlreadyExists;
 
         assert_eq!(
             outcome.collisions,
             vec![
                 Collision {
                     path: "FILE_x".into(),
-                    error_kind: ErrorKind::AlreadyExists,
+                    error_kind,
                 },
                 Collision {
                     path: "d".into(),
-                    error_kind: ErrorKind::AlreadyExists,
+                    error_kind,
                 },
                 Collision {
                     path: "file_X".into(),
-                    error_kind: ErrorKind::AlreadyExists,
+                    error_kind,
                 },
                 Collision {
                     path: "file_x".into(),
-                    error_kind: ErrorKind::AlreadyExists,
+                    error_kind,
                 },
             ],
             "these files couldn't be checked out"