validate that colliding files are checked out (#301)

git-worktree/src/index.rs

@@ -108,7 +108,7 @@ pub(crate) mod entry {
                     path: root.to_path_buf(),
                 })?;
                 let mut options = OpenOptions::new();
-                options.create_new(true).write(true);
+                options.create(true).write(true);
                 #[cfg(unix)]
                 if executable_bit && entry.mode == git_index::entry::Mode::FILE_EXECUTABLE {
                     use std::os::unix::fs::OpenOptionsExt;

git-worktree/tests/index/mod.rs

@@ -8,27 +8,19 @@ mod checkout {
 
     use git_object::bstr::ByteSlice;
     use git_odb::FindExt;
+    use git_worktree::fs::Capabilities;
     use git_worktree::index;
-    use git_worktree::index::checkout::Options;
     use tempfile::TempDir;
 
     use crate::fixture_path;
 
-    #[test]
-    fn allow_symlinks() -> crate::Result {
-        let opts = opts_with_symlink(true);
-        if !git_worktree::fs::Capabilities::probe(std::env::current_dir()?.join("..").join(".git")).symlink {
-            eprintln!("IGNORING symlink test on file system without symlink support");
-            // skip if symlinks aren't supported anyway.
-            return Ok(());
-        };
-        let (source_tree, destination) = setup_fixture_with_options(opts, "make_mixed_without_submodules")?;
-
-        assert_equality(&source_tree, &destination, opts.fs.symlink)?;
-        Ok(())
+    fn probe_gitoxide_dir() -> crate::Result<Capabilities> {
+        Ok(git_worktree::fs::Capabilities::probe(
+            std::env::current_dir()?.join("..").join(".git"),
+        ))
     }
 
-    fn opts_with_symlink(symlink: bool) -> Options {
+    fn opts_with_symlink(symlink: bool) -> index::checkout::Options {
         index::checkout::Options {
             fs: git_worktree::fs::Capabilities {
                 symlink,
@@ -41,14 +33,67 @@ mod checkout {
     #[test]
     fn symlinks_become_files_if_disabled() -> crate::Result {
         let opts = opts_with_symlink(false);
-        let (source_tree, destination) = setup_fixture_with_options(opts, "make_mixed_without_submodules")?;
+        let (source_tree, destination, _index) = checkout_index_in_tmp_dir(opts, "make_mixed_without_submodules")?;
 
         assert_equality(&source_tree, &destination, opts.fs.symlink)?;
 
         Ok(())
     }
 
-    fn assert_equality(source_tree: &Path, destination: &TempDir, allow_symlinks: bool) -> crate::Result {
+    #[test]
+    fn allow_symlinks() -> crate::Result {
+        let opts = opts_with_symlink(true);
+        if !probe_gitoxide_dir()?.symlink {
+            eprintln!("IGNORING symlink test on file system without symlink support");
+            // skip if symlinks aren't supported anyway.
+            return Ok(());
+        };
+        let (source_tree, destination, _index) = checkout_index_in_tmp_dir(opts, "make_mixed_without_submodules")?;
+
+        assert_equality(&source_tree, &destination, opts.fs.symlink)?;
+        Ok(())
+    }
+
+    #[test]
+    fn no_case_related_collisions_on_case_sensitive_filesystem() {
+        if probe_gitoxide_dir().unwrap().ignore_case {
+            eprintln!("Skipping case-sensitive testing on what would be a case-insenstive file system");
+            return;
+        }
+        let opts = opts_with_symlink(true);
+        let (source_tree, destination, index) = checkout_index_in_tmp_dir(opts, "make_ignorecase_collisions").unwrap();
+        assert_eq!(index.entries().len(), 2, "there is just one colliding item");
+
+        let num_files = assert_equality(&source_tree, &destination, opts.fs.symlink).unwrap();
+        assert_eq!(num_files, index.entries().len(), "it checks out all files");
+    }
+
+    #[test]
+    fn collisions_are_detected_on_a_case_sensitive_filesystem() {
+        if !probe_gitoxide_dir().unwrap().ignore_case {
+            eprintln!("Skipping case-insensitive testing on what would be a case-senstive file system");
+            return;
+        }
+        let opts = opts_with_symlink(true);
+        let (source_tree, destination, index) = checkout_index_in_tmp_dir(opts, "make_ignorecase_collisions").unwrap();
+        assert_eq!(index.entries().len(), 2, "there is just one colliding item");
+
+        let source_files = dir_structure(&source_tree);
+        assert_eq!(
+            stripped_prefix(&source_tree, &source_files),
+            vec![PathBuf::from("a")],
+            "the source also only contains the first created file"
+        );
+
+        let dest_files = dir_structure(&destination);
+        assert_eq!(
+            stripped_prefix(&destination, &dest_files),
+            vec![PathBuf::from("A")],
+            "it only creates the first file of a collision"
+        );
+    }
+
+    fn assert_equality(source_tree: &Path, destination: &TempDir, allow_symlinks: bool) -> crate::Result<usize> {
         let source_files = dir_structure(source_tree);
         let worktree_files = dir_structure(&destination);
 
@@ -57,7 +102,9 @@ mod checkout {
             stripped_prefix(&destination, &worktree_files),
         );
 
+        let mut count = 0;
         for (source_file, worktree_file) in source_files.iter().zip(worktree_files.iter()) {
+            count += 1;
             if !allow_symlinks && source_file.is_symlink() {
                 assert!(!worktree_file.is_symlink());
                 assert_eq!(fs::read(worktree_file)?.to_path()?, fs::read_link(source_file)?);
@@ -71,7 +118,7 @@ mod checkout {
                 );
             }
         }
-        Ok(())
+        Ok(count)
     }
 
     pub fn dir_structure<P: AsRef<std::path::Path>>(path: P) -> Vec<std::path::PathBuf> {
@@ -87,10 +134,10 @@ mod checkout {
         files
     }
 
-    fn setup_fixture_with_options(
-        opts: git_worktree::index::checkout::Options,
+    fn checkout_index_in_tmp_dir(
+        opts: index::checkout::Options,
         name: &str,
-    ) -> crate::Result<(PathBuf, TempDir)> {
+    ) -> crate::Result<(PathBuf, TempDir, git_index::File)> {
         let source_tree = fixture_path(name);
         let git_dir = source_tree.join(".git");
         let mut index = git_index::File::at(git_dir.join("index"), Default::default())?;
@@ -103,7 +150,7 @@ mod checkout {
             move |oid, buf| odb.find_blob(oid, buf).ok(),
             opts,
         )?;
-        Ok((source_tree, destination))
+        Ok((source_tree, destination, index))
     }
 
     fn stripped_prefix(prefix: impl AsRef<Path>, source_files: &[PathBuf]) -> Vec<&Path> {