git: fix mypy errors (#5073)

dvc/scm/git/__init__.py

@@ -6,7 +6,7 @@ import shlex
 from collections import OrderedDict
 from contextlib import contextmanager
 from functools import partialmethod
-from typing import Iterable, Optional
+from typing import Iterable, List, Optional, Set
 
 from funcy import cached_property, first
 from pathspec.patterns import GitWildMatchPattern
@@ -38,8 +38,8 @@ class Git(Base):
     def __init__(
         self, *args, backends: Optional[Iterable[str]] = None, **kwargs
     ):
-        self.ignored_paths = []
-        self.files_to_track = set()
+        self.ignored_paths: List[str] = []
+        self.files_to_track: Set[str] = set()
 
         selected = backends if backends else self.DEFAULT_BACKENDS.keys()
         self.backends = OrderedDict(
@@ -248,7 +248,7 @@ class Git(Base):
 
         self.add(self.files_to_track)
 
-    def track_file(self, path):
+    def track_file(self, path: str):
         self.files_to_track.add(path)
 
     def belongs_to_scm(self, path):

dvc/scm/git/backend/dulwich.py

@@ -334,7 +334,7 @@ class DulwichBackend(BaseGitBackend):  # pylint:disable=abstract-method
             raise SCMError("Git failed to push '{src}' to '{url}'") from exc
 
     def _push_dest_refs(
-        self, src: str, dest: str
+        self, src: Optional[str], dest: str
     ) -> Tuple[Iterable[bytes], Iterable[bytes]]:
         from dulwich.objects import ZERO_SHA
 

dvc/scm/git/backend/gitpython.py

@@ -408,9 +408,7 @@ class GitPythonBackend(BaseGitBackend):  # pylint:disable=abstract-method
         from git import Reference
 
         for ref in Reference.iter_items(self.repo, common_path=base):
-            if base and base.endswith("/"):
-                base = base[:-1]
-            yield "/".join([base, ref.name])
+            yield ref.path
 
     def iter_remote_refs(self, url: str, base: Optional[str] = None):
         raise NotImplementedError