dulwich: fix output of describe(#4)

scmrepo/git/__init__.py

@@ -314,7 +314,7 @@ def add_commit(
     _stash_push = partialmethod(_backend_func, "_stash_push")
     _stash_apply = partialmethod(_backend_func, "_stash_apply")
     _stash_drop = partialmethod(_backend_func, "_stash_drop")
-    describe = partialmethod(_backend_func, "describe")
+    _describe = partialmethod(_backend_func, "_describe")
     diff = partialmethod(_backend_func, "diff")
     reset = partialmethod(_backend_func, "reset")
     checkout_index = partialmethod(_backend_func, "checkout_index")
@@ -397,3 +397,18 @@ def stash_workspace(self, **kwargs):
 
     def _reset(self) -> None:
         self.backends.reset_all()
+
+    def describe(
+        self,
+        rev: str,
+        base: Optional[str] = None,
+        match: Optional[str] = None,
+        exclude: Optional[str] = None,
+    ) -> Optional[str]:
+        if (
+            base == "refs/heads"
+            and self.get_rev() == rev
+            and self.get_ref("HEAD", follow=False).startswith(base)
+        ):
+            return self.get_ref("HEAD", follow=False)
+        return self._describe(rev, base, match, exclude)

scmrepo/git/backend/base.py

@@ -278,7 +278,7 @@ def _stash_drop(self, ref: str, index: int):
         """Drop the specified stash revision."""
 
     @abstractmethod
-    def describe(
+    def _describe(
         self,
         rev: str,
         base: Optional[str] = None,

scmrepo/git/backend/dulwich/__init__.py

@@ -590,7 +590,7 @@ def _stash_drop(self, ref: str, index: int):
         except ValueError as exc:
             raise SCMError("Failed to drop stash entry") from exc
 
-    def describe(
+    def _describe(
         self,
         rev: str,
         base: Optional[str] = None,

scmrepo/git/backend/gitpython.py

@@ -552,7 +552,7 @@ def _stash_drop(self, ref: str, index: int):
         except GitCommandError:
             self.remove_ref(ref)
 
-    def describe(
+    def _describe(
         self,
         rev: str,
         base: Optional[str] = None,

scmrepo/git/backend/pygit2.py

@@ -459,7 +459,7 @@ def _stash_drop(self, ref: str, index: int):
 
         self.repo.stash_drop(index)
 
-    def describe(
+    def _describe(
         self,
         rev: str,
         base: Optional[str] = None,

tests/test_git.py

@@ -607,3 +607,30 @@ def test_checkout_subdir(tmp_dir: TmpDir, scm: Git, git: Git):
     with (tmp_dir / "dir").chdir():
         git.checkout(rev)
         assert not (tmp_dir / "dir" / "bar").exists()
+
+
+@pytest.mark.skip_git_backend("pygit2", "gitpython")
+def test_describe(tmp_dir: TmpDir, scm: Git, git: Git):
+    tmp_dir.gen({"foo": "foo"})
+    scm.add_commit("foo", message="foo")
+    rev_foo = scm.get_rev()
+
+    tmp_dir.gen({"foo": "bar"})
+    scm.add_commit("foo", message="bar")
+    rev_bar = scm.get_rev()
+
+    assert git.describe(rev_foo, "refs/heads") is None
+
+    scm.checkout("branch", create_new=True)
+    assert git.describe(rev_bar, "refs/heads") == "refs/heads/branch"
+
+    tmp_dir.gen({"foo": "foobar"})
+    scm.add_commit("foo", message="foobar")
+    rev_foobar = scm.get_rev()
+
+    scm.checkout("master")
+    assert git.describe(rev_bar, "refs/heads") == "refs/heads/master"
+    assert git.describe(rev_foobar, "refs/heads") == "refs/heads/branch"
+
+    scm.tag("tag")
+    assert git.describe(rev_bar) == "refs/tags/tag"