Fix problem with Win10 shell

src/pyscaffold/file_system.py

@@ -11,14 +11,14 @@
 import os
 import shutil
 import stat
-import sys
 from contextlib import contextmanager
 from functools import partial
 from pathlib import Path
 from tempfile import mkstemp
 from typing import Callable, Optional, Union
 
 from .log import logger
+from .shell import IS_WINDOWS
 
 PathLike = Union[str, os.PathLike]
 
@@ -216,11 +216,7 @@ def is_pathname_valid(pathname: str) -> bool:
         # Directory guaranteed to exist. If the current OS is Windows, this is
         # the drive to which Windows was installed (e.g., the "%HOMEDRIVE%"
         # environment variable); else, the typical root directory.
-        root_dirname = (
-            os.environ.get("HOMEDRIVE", "C:")
-            if sys.platform == "win32"
-            else os.path.sep
-        )
+        root_dirname = os.environ.get("HOMEDRIVE", "C:") if IS_WINDOWS else os.path.sep
         assert os.path.isdir(root_dirname)  # ...Murphy and her ironclad Law
 
         # Append a path separator to this directory if needed.

src/pyscaffold/shell.py

@@ -8,6 +8,7 @@
 import shutil
 import subprocess
 import sys
+from itertools import product
 from pathlib import Path
 from typing import Callable, Dict, Iterable, Iterator, List, Optional, Union
 
@@ -17,6 +18,7 @@
 PathLike = Union[str, os.PathLike]
 
 IS_POSIX = os.name == "posix"
+IS_WINDOWS = sys.platform == "win32"
 
 # The following default flags were borrowed from Github's docs:
 # https://docs.github.com/en/github/getting-started-with-github/associating-text-editors-with-git
@@ -65,6 +67,23 @@ def __init__(self, command: str, shell: bool = True, cwd: Optional[str] = None):
         self._shell = shell
         self._cwd = cwd
 
+    def _no_git_env(self, env: Dict[str, str]) -> Dict[str, str]:
+        # adapted from pre-commit & taken from setuptools-scm
+        # 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
+        # pre-commit hooks
+        # In git 1.9.1 (maybe others), git exports GIT_DIR and GIT_INDEX_FILE
+        # while running pre-commit hooks in submodules.
+        # GIT_DIR: Causes git clone to clone wrong thing
+        # GIT_INDEX_FILE: Causes 'error invalid object ...' during commit
+        return {
+            k: v
+            for k, v in env.items()
+            if not k.startswith("GIT_")
+            or k in ("GIT_EXEC_PATH", "GIT_SSH", "GIT_SSH_COMMAND")
+        }
+
     def run(self, *args, **kwargs) -> subprocess.CompletedProcess:
         """Execute command with the given arguments via :obj:`subprocess.run`."""
         command = f"{self._command} {join(args)}".strip()
@@ -86,6 +105,14 @@ def run(self, *args, **kwargs) -> subprocess.CompletedProcess:
             "stdout": subprocess.PIPE,
             "stderr": subprocess.STDOUT,
             "universal_newlines": True,
+            "env": dict(
+                self._no_git_env(dict(os.environ)),
+                # os.environ,
+                # try to disable i18n
+                LC_ALL="C",
+                LANGUAGE="",
+                HGPLAIN="1",
+            ),
             **kwargs,  # allow overwriting defaults
         }
         if self._shell:
@@ -131,10 +158,10 @@ def get_git_cmd(**args):
     Args:
         **args: additional keyword arguments to :obj:`~.ShellCommand`
     """
-    if sys.platform == "win32":  # pragma: no cover
+    if IS_WINDOWS:  # pragma: no cover
         # ^  CI setup does not aggregate Windows coverage
-        for cmd in ["git.cmd", "git.exe"]:
-            git = ShellCommand(cmd, **args)
+        for shell, cmd in product([True, False], ["git.cmd", "git.exe"]):
+            git = ShellCommand(cmd, shell=shell, **args)
             try:
                 git("--version")
             except ShellCommandException:
@@ -237,7 +264,7 @@ def edit(file: PathLike, *args, **kwargs) -> Path:
 
 def join(parts: Iterable[Union[str, PathLike]]) -> str:
     """Join different parts of a shell command into a string, quoting whitespaces."""
-    if sys.platform == "win32":  # pragma: no cover
+    if IS_WINDOWS:  # pragma: no cover
         # ^  CI setup does not aggregate Windows coverage
         return subprocess.list2cmdline(map(str, parts))