feat(reset): add ability to remove entries in index

lib/src/bindings/reset.dart

@@ -28,12 +28,15 @@ void reset({
 /// Updates some entries in the index from the target commit tree.
 ///
 /// The scope of the updated entries is determined by the paths being passed in
-/// the pathspec parameters.
+/// the [pathspec] parameters.
+///
+/// Passing a null [targetPointer] will result in removing entries in the index
+/// matching the provided [pathspec]s.
 ///
 /// Throws a [LibGit2Error] if error occured.
 void resetDefault({
   required Pointer<git_repository> repoPointer,
-  required Pointer<git_object> targetPointer,
+  required Pointer<git_object>? targetPointer,
   required List<String> pathspec,
 }) {
   final pathspecC = calloc<git_strarray>();
@@ -50,7 +53,7 @@ void resetDefault({
 
   final error = libgit2.git_reset_default(
     repoPointer,
-    targetPointer,
+    targetPointer ?? nullptr,
     pathspecC,
   );
 

lib/src/repository.dart

@@ -578,13 +578,19 @@ class Repository extends Equatable {
   /// The scope of the updated entries is determined by the paths being passed
   /// in the [pathspec].
   ///
+  /// Passing a null [oid] will result in removing entries in the index
+  /// matching the provided [pathspec]s.
+  ///
   /// Throws a [LibGit2Error] if error occured.
-  void resetDefault({required Oid oid, required List<String> pathspec}) {
+  void resetDefault({required Oid? oid, required List<String> pathspec}) {
-    final object = object_bindings.lookup(
+    Pointer<git_object>? object;
+    if (oid != null) {
+      object = object_bindings.lookup(
         repoPointer: _repoPointer,
         oidPointer: oid.pointer,
         type: GitObject.commit.value,
       );
+    }
 
     reset_bindings.resetDefault(
       repoPointer: _repoPointer,

test/reset_test.dart

@@ -61,6 +61,17 @@ void main() {
         expect(repo.status['feature_file'], {GitStatus.wtModified});
       });
 
+      test('removes entry in the index when null oid is provided', () {
+        const fileName = 'new_file.txt';
+        File(p.join(tmpDir.path, fileName)).createSync();
+
+        repo.index.add(fileName);
+        expect(repo.status[fileName], {GitStatus.indexNew});
+
+        repo.resetDefault(oid: null, pathspec: [fileName]);
+        expect(repo.status[fileName], {GitStatus.wtNew});
+      });
+
       test('throws when pathspec list is empty', () {
         expect(
           () => repo.resetDefault(oid: repo.head.target, pathspec: []),