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]
 
@@ -199,11 +199,7 @@ 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

@@ -18,6 +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
@@ -61,7 +62,12 @@ class ShellCommand:
     character, ``command`` needs to be properly quoted.
     """
 
-    def __init__(self, command: str, shell: bool = True, cwd: Optional[str] = None):
+    def __init__(
+        self,
+        command: str,
+        shell: bool = True,
+        cwd: Optional[str] = None,
+    ):
         self._command = command
         self._shell = shell
         self._cwd = cwd
@@ -81,6 +87,11 @@ def run(self, *args, **kwargs) -> subprocess.CompletedProcess:
             "stdout": subprocess.PIPE,
             "stderr": subprocess.STDOUT,
             "universal_newlines": True,
+            "env": {
+                **os.environ,
+                # try to disable i18n
+                **dict(LC_ALL="C", LANGUAGE=""),
+            },
             **kwargs,  # allow overwriting defaults
         }
         if self._shell:
@@ -91,16 +102,22 @@ def run(self, *args, **kwargs) -> subprocess.CompletedProcess:
 
     def __call__(self, *args, **kwargs) -> Iterator[str]:
         """Execute the command, returning an iterator for the resulting text output"""
-        completed = self.run(*args, **kwargs)
+        try:
+            completed = self.run(*args, **kwargs)
+        except FileNotFoundError as e:
+            msg = f"{e.strerror}: {e.filename}"
+            logger.debug(f'last command failed with "{msg}"')
+            raise ShellCommandException(msg) from e
+
         try:
             completed.check_returncode()
-        except subprocess.CalledProcessError as ex:
+        except subprocess.CalledProcessError as e:
             stdout, stderr = (e or "" for e in (completed.stdout, completed.stderr))
             stdout, stderr = (e.strip() for e in (stdout, stderr))
-            sep = " :: " if stdout and stderr else ""
+            sep = "; " if stdout and stderr else ""
             msg = sep.join([stdout, stderr])
             logger.debug(f'last command failed with "{msg}"')
-            raise ShellCommandException(msg) from ex
+            raise ShellCommandException(msg) from e
 
         return (line for line in (completed.stdout or "").splitlines())
 
@@ -132,10 +149,10 @@ 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 in (True, False):
+            git = ShellCommand("git.exe", shell=shell, **args)
             try:
                 git("--version")
             except ShellCommandException:
@@ -238,7 +255,7 @@ 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))
 

tests/test_shell.py

@@ -162,3 +162,9 @@ def test_join():
     # Join should be the opposite of split
     args = ["/my path/to exec", '"other args"', "asdf", "42", "'a b c'"]
     assert shlex.split(shell.join(args)) == args
+
+
+def test_non_existent_file_exception():
+    cmd = shell.ShellCommand("non_existent_cmd", shell=False)
+    with pytest.raises(shell.ShellCommandException):
+        cmd()