@@ -6,12 +6,16 @@
 )
 from gitdb.db import GitDB  # @UnusedImport
 from gitdb.db import LooseObjectDB
+from gitdb.exc import BadObject
 
-from .exc import (
-    GitCommandError,
-    BadObject
-)
+from .exc import GitCommandError
+
+# typing-------------------------------------------------
+
+from .cmd import Git
+from .types import PathLike, TBD
 
+# --------------------------------------------------------
 
 __all__ = ('GitCmdObjectDB', 'GitDB')
 
@@ -28,23 +32,23 @@ class GitCmdObjectDB(LooseObjectDB):
         have packs and the other implementations
     """
 
-    def __init__(self, root_path, git):
+    def __init__(self, root_path: PathLike, git: Git) -> None:
         """Initialize this instance with the root and a git command"""
         super(GitCmdObjectDB, self).__init__(root_path)
         self._git = git
 
-    def info(self, sha):
+    def info(self, sha: bytes) -> OInfo:
         hexsha, typename, size = self._git.get_object_header(bin_to_hex(sha))
         return OInfo(hex_to_bin(hexsha), typename, size)
 
-    def stream(self, sha):
+    def stream(self, sha: bytes) -> OStream:
         """For now, all lookup is done by git itself"""
         hexsha, typename, size, stream = self._git.stream_object_data(bin_to_hex(sha))
         return OStream(hex_to_bin(hexsha), typename, size, stream)
 
     # { Interface
 
-    def partial_to_complete_sha_hex(self, partial_hexsha):
+    def partial_to_complete_sha_hex(self, partial_hexsha: str) -> bytes:
         """:return: Full binary 20 byte sha from the given partial hexsha
         :raise AmbiguousObjectName:
         :raise BadObject:
 
@@ -8,6 +8,13 @@
 from gitdb.exc import *     # NOQA @UnusedWildImport skipcq: PYL-W0401, PYL-W0614
 from git.compat import safe_decode
 
+# typing ----------------------------------------------------
+
+from git.repo.base import Repo
+from git.types import PathLike
+from typing import IO, List, Optional, Sequence, Tuple, Union
+
+# ------------------------------------------------------------------
 
 class GitError(Exception):
     """ Base class for all package exceptions """
@@ -37,7 +44,9 @@ class CommandError(GitError):
     #:     "'%s' failed%s"
     _msg = "Cmd('%s') failed%s"
 
-    def __init__(self, command, status=None, stderr=None, stdout=None):
+    def __init__(self, command: Union[List[str], Tuple[str, ...], str], 
+                 status: Union[str, None, Exception] = None,
+                 stderr: Optional[IO[str]] = None, stdout: Optional[IO[str]] = None) -> None:
         if not isinstance(command, (tuple, list)):
             command = command.split()
         self.command = command
@@ -53,28 +62,33 @@ def __init__(self, command, status=None, stderr=None, stdout=None):
                     status = "'%s'" % s if isinstance(status, str) else s
 
         self._cmd = safe_decode(command[0])
-        self._cmdline = ' '.join(safe_decode(i) for i in command)
+        self._cmdline = ' '.join(str(safe_decode(i)) for i in command)
         self._cause = status and " due to: %s" % status or "!"
-        self.stdout = stdout and "\n  stdout: '%s'" % safe_decode(stdout) or ''
-        self.stderr = stderr and "\n  stderr: '%s'" % safe_decode(stderr) or ''
+        self.stdout = stdout and "\n  stdout: '%s'" % safe_decode(str(stdout)) or ''
+        self.stderr = stderr and "\n  stderr: '%s'" % safe_decode(str(stderr)) or ''
 
-    def __str__(self):
+    def __str__(self) -> str:
         return (self._msg + "\n  cmdline: %s%s%s") % (
             self._cmd, self._cause, self._cmdline, self.stdout, self.stderr)
 
 
 class GitCommandNotFound(CommandError):
     """Thrown if we cannot find the `git` executable in the PATH or at the path given by
     the GIT_PYTHON_GIT_EXECUTABLE environment variable"""
-    def __init__(self, command, cause):
+
+    def __init__(self, command: Union[List[str], Tuple[str], str], cause: Union[str, Exception]) -> None:
         super(GitCommandNotFound, self).__init__(command, cause)
         self._msg = "Cmd('%s') not found%s"
 
 
 class GitCommandError(CommandError):
     """ Thrown if execution of the git command fails with non-zero status code. """
 
-    def __init__(self, command, status, stderr=None, stdout=None):
+    def __init__(self, command: Union[List[str], Tuple[str, ...], str], 
+                 status: Union[str, None, Exception] = None,
+                 stderr: Optional[IO[str]] = None,
+                 stdout: Optional[IO[str]] = None,
+                 ) -> None:
         super(GitCommandError, self).__init__(command, status, stderr, stdout)
 
 
@@ -92,13 +106,13 @@ class CheckoutError(GitError):
     were checked out successfully and hence match the version stored in the
     index"""
 
-    def __init__(self, message, failed_files, valid_files, failed_reasons):
+    def __init__(self, message: str, failed_files: List[PathLike], valid_files: List[PathLike], failed_reasons: List[str]) -> None:
         Exception.__init__(self, message)
         self.failed_files = failed_files
         self.failed_reasons = failed_reasons
         self.valid_files = valid_files
 
-    def __str__(self):
+    def __str__(self) -> str:
         return Exception.__str__(self) + ":%s" % self.failed_files
 
 
@@ -116,17 +130,18 @@ class HookExecutionError(CommandError):
     """Thrown if a hook exits with a non-zero exit code. It provides access to the exit code and the string returned
     via standard output"""
 
-    def __init__(self, command, status, stderr=None, stdout=None):
+    def __init__(self, command: Union[List[str], Tuple[str, ...], str], status: Optional[str],
+                 stderr: Optional[IO[str]] = None, stdout: Optional[IO[str]] = None) -> None:
         super(HookExecutionError, self).__init__(command, status, stderr, stdout)
         self._msg = "Hook('%s') failed%s"
 
 
 class RepositoryDirtyError(GitError):
     """Thrown whenever an operation on a repository fails as it has uncommitted changes that would be overwritten"""
 
-    def __init__(self, repo, message):
+    def __init__(self, repo: Repo, message: str) -> None:
         self.repo = repo
         self.message = message
 
-    def __str__(self):
+    def __str__(self) -> str:
         return "Operation cannot be performed on %r: %s" % (self.repo, self.message)
@@ -2,3 +2,5 @@
 [mypy]
 
 disallow_untyped_defs = True
+
+mypy_path = 'git'
-Original file line number
+Diff line change
@@ @@ -2,3 +2,5 @@ @@
 [mypy]
 disallow_untyped_defs = True
++
 +mypy_path = 'git'