pre-commit · asottile · Oct 28, 2020 · Oct 28, 2020
diff --git a/pre_commit/commands/run.py b/pre_commit/commands/run.py
@@ -11,6 +11,7 @@
 from typing import Collection
 from typing import Dict
 from typing import List
+from typing import MutableMapping
 from typing import Sequence
 from typing import Set
 from typing import Tuple
@@ -28,7 +29,6 @@
 from pre_commit.staged_files_only import staged_files_only
 from pre_commit.store import Store
 from pre_commit.util import cmd_output_b
-from pre_commit.util import EnvironT
 
 
 logger = logging.getLogger('pre_commit')
@@ -116,7 +116,7 @@ def from_config(
         return Classifier(filenames)
 
 
-def _get_skips(environ: EnvironT) -> Set[str]:
+def _get_skips(environ: MutableMapping[str, str]) -> Set[str]:
     skips = environ.get('SKIP', '')
     return {skip.strip() for skip in skips.split(',') if skip.strip()}
 
@@ -258,7 +258,7 @@ def _run_hooks(
         config: Dict[str, Any],
         hooks: Sequence[Hook],
         args: argparse.Namespace,
-        environ: EnvironT,
+        environ: MutableMapping[str, str],
 ) -> int:
     """Actually run the hooks."""
     skips = _get_skips(environ)
@@ -315,7 +315,7 @@ def run(
         config_file: str,
         store: Store,
         args: argparse.Namespace,
-        environ: EnvironT = os.environ,
+        environ: MutableMapping[str, str] = os.environ,
 ) -> int:
     stash = not args.all_files and not args.files
 

diff --git a/pre_commit/envcontext.py b/pre_commit/envcontext.py
@@ -2,13 +2,12 @@
 import enum
 import os
 from typing import Generator
+from typing import MutableMapping
 from typing import NamedTuple
 from typing import Optional
 from typing import Tuple
 from typing import Union
 
-from pre_commit.util import EnvironT
-
 
 class _Unset(enum.Enum):
     UNSET = 1
@@ -27,7 +26,7 @@ class Var(NamedTuple):
 PatchesT = Tuple[Tuple[str, ValueT], ...]
 
 
-def format_env(parts: SubstitutionT, env: EnvironT) -> str:
+def format_env(parts: SubstitutionT, env: MutableMapping[str, str]) -> str:
     return ''.join(
         env.get(part.name, part.default) if isinstance(part, Var) else part
         for part in parts
@@ -37,7 +36,7 @@ def format_env(parts: SubstitutionT, env: EnvironT) -> str:
 @contextlib.contextmanager
 def envcontext(
         patch: PatchesT,
-        _env: Optional[EnvironT] = None,
+        _env: Optional[MutableMapping[str, str]] = None,
 ) -> Generator[None, None, None]:
     """In this context, `os.environ` is modified according to `patch`.
 
@@ -50,7 +49,7 @@ def envcontext(
               replaced with the previous environment
     """
     env = os.environ if _env is None else _env
-    before = env.copy()
+    before = dict(env)
 
     for k, v in patch:
         if v is UNSET:

diff --git a/pre_commit/git.py b/pre_commit/git.py
@@ -3,14 +3,14 @@
 import sys
 from typing import Dict
 from typing import List
+from typing import MutableMapping
 from typing import Optional
 from typing import Set
 
 from pre_commit.errors import FatalError
 from pre_commit.util import CalledProcessError
 from pre_commit.util import cmd_output
 from pre_commit.util import cmd_output_b
-from pre_commit.util import EnvironT
 
 
 logger = logging.getLogger(__name__)
@@ -24,7 +24,9 @@ def zsplit(s: str) -> List[str]:
         return []
 
 
-def no_git_env(_env: Optional[EnvironT] = None) -> Dict[str, str]:
+def no_git_env(
+        _env: Optional[MutableMapping[str, str]] = None,
+) -> Dict[str, str]:
     # Too many bugs dealing with environment variables and GIT:
     # https://github.com/pre-commit/pre-commit/issues/300
     # In git 2.6.3 (maybe others), git exports GIT_WORK_TREE while running

diff --git a/pre_commit/util.py b/pre_commit/util.py
@@ -16,7 +16,6 @@
 from typing import Optional
 from typing import Tuple
 from typing import Type
-from typing import Union
 
 import yaml
 
@@ -29,8 +28,6 @@
     from importlib_resources import open_binary
     from importlib_resources import read_text
 
-EnvironT = Union[Dict[str, str], 'os._Environ']
-
 Loader = getattr(yaml, 'CSafeLoader', yaml.SafeLoader)
 yaml_load = functools.partial(yaml.load, Loader=Loader)
 Dumper = getattr(yaml, 'CSafeDumper', yaml.SafeDumper)

diff --git a/pre_commit/xargs.py b/pre_commit/xargs.py
@@ -9,6 +9,7 @@
 from typing import Generator
 from typing import Iterable
 from typing import List
+from typing import MutableMapping
 from typing import Optional
 from typing import Sequence
 from typing import Tuple
@@ -17,13 +18,12 @@
 from pre_commit import parse_shebang
 from pre_commit.util import cmd_output_b
 from pre_commit.util import cmd_output_p
-from pre_commit.util import EnvironT
 
 TArg = TypeVar('TArg')
 TRet = TypeVar('TRet')
 
 
-def _environ_size(_env: Optional[EnvironT] = None) -> int:
+def _environ_size(_env: Optional[MutableMapping[str, str]] = None) -> int:
     environ = _env if _env is not None else getattr(os, 'environb', os.environ)
     size = 8 * len(environ)  # number of pointers in `envp`
     for k, v in environ.items():

diff --git a/tests/commands/run_test.py b/tests/commands/run_test.py
@@ -2,6 +2,7 @@
 import shlex
 import sys
 import time
+from typing import MutableMapping
 from unittest import mock
 
 import pytest
@@ -18,7 +19,6 @@
 from pre_commit.commands.run import filter_by_include_exclude
 from pre_commit.commands.run import run
 from pre_commit.util import cmd_output
-from pre_commit.util import EnvironT
 from pre_commit.util import make_executable
 from testing.auto_namedtuple import auto_namedtuple
 from testing.fixtures import add_config_to_repo
@@ -482,7 +482,7 @@ def test_all_push_options_ok(cap_out, store, repo_with_passing_hook):
 
 def test_checkout_type(cap_out, store, repo_with_passing_hook):
     args = run_opts(from_ref='', to_ref='', checkout_type='1')
-    environ: EnvironT = {}
+    environ: MutableMapping[str, str] = {}
     ret, printed = _do_run(
         cap_out, store, repo_with_passing_hook, args, environ,
     )
@@ -1032,7 +1032,7 @@ def test_skipped_without_any_setup_for_post_checkout(in_git_dir, store):
 
 def test_pre_commit_env_variable_set(cap_out, store, repo_with_passing_hook):
     args = run_opts()
-    environ: EnvironT = {}
+    environ: MutableMapping[str, str] = {}
     ret, printed = _do_run(
         cap_out, store, repo_with_passing_hook, args, environ,
     )