dulwich: use untracked_files="no" in is_dirty

This will speed up calling `is_dirty` with untracked_files=False

related to #69

Author: dtrifiro

scmrepo/git/backend/dulwich/__init__.py

@@ -7,6 +7,7 @@
 from io import BytesIO, StringIO
 from typing import (
     TYPE_CHECKING,
+    Any,
     Callable,
     Dict,
     Iterable,
@@ -344,8 +345,10 @@ def is_tracked(self, path: str) -> bool:
         return False
 
     def is_dirty(self, untracked_files: bool = False) -> bool:
-        staged, unstaged, untracked = self.status()
-        return bool(staged or unstaged or (untracked_files and untracked))
+        kwargs: Dict[str, Any] = (
+            {} if untracked_files else {"untracked_files": "no"}
+        )
+        return any(self.status(**kwargs))
 
     def active_branch(self) -> str:
         raise NotImplementedError

tests/test_git.py

@@ -1041,3 +1041,32 @@ def test_status(
     assert staged["modify"] == ["foo"]
     assert unstaged == ["bar"]
     assert untracked == expected_untracked
+
+
+@pytest.mark.skip_git_backend("pygit2")
+def test_is_dirty(
+    tmp_dir: TmpDir,
+    scm: Git,
+    git: Git,
+):
+    tmp_dir.gen("foo", "foo")
+    scm.add("foo")
+    assert git.is_dirty()
+    scm.commit("commit")
+    assert not git.is_dirty()
+
+    tmp_dir.gen("foo", "modified")
+    assert git.is_dirty()
+    scm.add_commit("foo", message="modified")
+    assert not git.is_dirty()
+
+    os.unlink(tmp_dir / "foo")
+    assert git.is_dirty()
+    scm.add("foo")
+    assert git.is_dirty()
+    scm.commit("deleted")
+    assert not git.is_dirty()
+
+    tmp_dir.gen("untracked", "untracked")
+    assert git.is_dirty(untracked_files=True)
+    assert not git.is_dirty(untracked_files=False)