Improve how second-level imports and __all__ are written

These are in the modules that are directly under the top-level git
module (and are not themselves subpackages, with their own
submodules in the Python sense), except for:

- git.util, where this change was very recently made.

- git.compat, where no improvements of this kind were needed.

- git.types, which currently has no __all__ and will only benefit from
  it if what should go in it is carefully considered (and where the
  imports themselves are grouped, sorted, and formatted already).

Author: EliahKagan

Diff for: git/cmd.py

@@ -5,18 +5,20 @@
 
 from __future__ import annotations
 
-import re
+__all__ = ("Git",)
+
 import contextlib
 import io
 import itertools
 import logging
 import os
+import re
 import signal
-from subprocess import Popen, PIPE, DEVNULL
 import subprocess
+from subprocess import DEVNULL, PIPE, Popen
 import sys
-import threading
 from textwrap import dedent
+import threading
 
 from git.compat import defenc, force_bytes, safe_decode
 from git.exc import (
@@ -57,12 +59,11 @@
     overload,
 )
 
-from git.types import PathLike, Literal, TBD
+from git.types import Literal, PathLike, TBD
 
 if TYPE_CHECKING:
-    from git.repo.base import Repo
     from git.diff import DiffIndex
-
+    from git.repo.base import Repo
 
 # ---------------------------------------------------------------------------------
 
@@ -84,8 +85,6 @@
 
 _logger = logging.getLogger(__name__)
 
-__all__ = ("Git",)
-
 
 # ==============================================================================
 ## @name Utilities

Diff for: git/config.py

@@ -5,6 +5,8 @@
 
 """Parser for reading and writing configuration files."""
 
+__all__ = ("GitConfigParser", "SectionConstraint")
+
 import abc
 import configparser as cp
 import fnmatch
@@ -40,9 +42,10 @@
 from git.types import Lit_config_levels, ConfigLevels_Tup, PathLike, assert_never, _T
 
 if TYPE_CHECKING:
-    from git.repo.base import Repo
     from io import BytesIO
 
+    from git.repo.base import Repo
+
 T_ConfigParser = TypeVar("T_ConfigParser", bound="GitConfigParser")
 T_OMD_value = TypeVar("T_OMD_value", str, bytes, int, float, bool)
 
@@ -58,8 +61,6 @@
 
 # -------------------------------------------------------------
 
-__all__ = ("GitConfigParser", "SectionConstraint")
-
 _logger = logging.getLogger(__name__)
 
 CONFIG_LEVELS: ConfigLevels_Tup = ("system", "user", "global", "repository")

Diff for: git/db.py

@@ -3,27 +3,26 @@
 
 """Module with our own gitdb implementation - it uses the git command."""
 
-from git.util import bin_to_hex, hex_to_bin
-from gitdb.base import OInfo, OStream
-from gitdb.db import GitDB
-from gitdb.db import LooseObjectDB
+__all__ = ("GitCmdObjectDB", "GitDB")
 
+from gitdb.base import OInfo, OStream
+from gitdb.db import GitDB, LooseObjectDB
 from gitdb.exc import BadObject
+
+from git.util import bin_to_hex, hex_to_bin
 from git.exc import GitCommandError
 
 # typing-------------------------------------------------
 
 from typing import TYPE_CHECKING
+
 from git.types import PathLike
 
 if TYPE_CHECKING:
     from git.cmd import Git
 
-
 # --------------------------------------------------------
 
-__all__ = ("GitCmdObjectDB", "GitDB")
-
 
 class GitCmdObjectDB(LooseObjectDB):
     """A database representing the default git object store, which includes loose

Diff for: git/diff.py

@@ -3,17 +3,17 @@
 # This module is part of GitPython and is released under the
 # 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/
 
+__all__ = ("DiffConstants", "NULL_TREE", "INDEX", "Diffable", "DiffIndex", "Diff")
+
 import enum
 import re
 
 from git.cmd import handle_process_output
 from git.compat import defenc
+from git.objects.blob import Blob
+from git.objects.util import mode_str_to_int
 from git.util import finalize_process, hex_to_bin
 
-from .objects.blob import Blob
-from .objects.util import mode_str_to_int
-
-
 # typing ------------------------------------------------------------------
 
 from typing import (
@@ -23,29 +23,27 @@
     Match,
     Optional,
     Tuple,
+    TYPE_CHECKING,
     TypeVar,
     Union,
-    TYPE_CHECKING,
     cast,
 )
 from git.types import Literal, PathLike
 
 if TYPE_CHECKING:
-    from .objects.tree import Tree
-    from .objects import Commit
-    from git.repo.base import Repo
-    from git.objects.base import IndexObject
     from subprocess import Popen
-    from git import Git
+
+    from git.cmd import Git
+    from git.objects.base import IndexObject
+    from git.objects.commit import Commit
+    from git.objects.tree import Tree
+    from git.repo.base import Repo
 
 Lit_change_type = Literal["A", "D", "C", "M", "R", "T", "U"]
 
 # ------------------------------------------------------------------------
 
 
-__all__ = ("DiffConstants", "NULL_TREE", "INDEX", "Diffable", "DiffIndex", "Diff")
-
-
 @enum.unique
 class DiffConstants(enum.Enum):
     """Special objects for :meth:`Diffable.diff`.

Diff for: git/exc.py

@@ -42,12 +42,14 @@
     ParseError,
     UnsupportedOperation,
 )
+
 from git.compat import safe_decode
 from git.util import remove_password_if_present
 
 # typing ----------------------------------------------------
 
-from typing import List, Sequence, Tuple, Union, TYPE_CHECKING
+from typing import List, Sequence, Tuple, TYPE_CHECKING, Union
+
 from git.types import PathLike
 
 if TYPE_CHECKING:

Diff for: git/remote.py

@@ -5,6 +5,8 @@
 
 """Module implementing a remote object allowing easy access to git remotes."""
 
+__all__ = ("RemoteProgress", "PushInfo", "FetchInfo", "Remote")
+
 import contextlib
 import logging
 import re
@@ -54,8 +56,6 @@
 
 _logger = logging.getLogger(__name__)
 
-__all__ = ("RemoteProgress", "PushInfo", "FetchInfo", "Remote")
-
 # { Utilities