Merging upstream version 2.17.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

pre_commit/commands/install_uninstall.py

@@ -1,4 +1,3 @@
-import itertools
 import logging
 import os.path
 import shlex
@@ -31,10 +30,6 @@ PRIOR_HASHES = (
 CURRENT_HASH = b'138fd403232d2ddd5efb44317e38bf03'
 TEMPLATE_START = '# start templated\n'
 TEMPLATE_END = '# end templated\n'
-# Homebrew/homebrew-core#35825: be more timid about appropriate `PATH`
-# #1312 os.defpath is too restrictive on BSD
-POSIX_SEARCH_PATH = ('/usr/local/bin', '/usr/bin', '/bin')
-SYS_EXE = os.path.basename(os.path.realpath(sys.executable))
 
 
 def _hook_paths(
@@ -54,26 +49,6 @@ def is_our_script(filename: str) -> bool:
     return any(h in contents for h in (CURRENT_HASH,) + PRIOR_HASHES)
 
 
-def shebang() -> str:
-    if sys.platform == 'win32':
-        py, _ = os.path.splitext(SYS_EXE)
-    else:
-        exe_choices = [
-            f'python{sys.version_info[0]}.{sys.version_info[1]}',
-            f'python{sys.version_info[0]}',
-        ]
-        # avoid searching for bare `python` as it's likely to be python 2
-        if SYS_EXE != 'python':
-            exe_choices.append(SYS_EXE)
-        for path, exe in itertools.product(POSIX_SEARCH_PATH, exe_choices):
-            if os.access(os.path.join(path, exe), os.X_OK):
-                py = exe
-                break
-        else:
-            py = SYS_EXE
-    return f'#!/usr/bin/env {py}'
-
-
 def _install_hook_script(
         config_file: str,
         hook_type: str,
@@ -107,6 +82,13 @@ def _install_hook_script(
         before, rest = contents.split(TEMPLATE_START)
         _, after = rest.split(TEMPLATE_END)
 
+        # on windows always use `/bin/sh` since `bash` might not be on PATH
+        # though we use bash-specific features `sh` on windows is actually
+        # bash in "POSIXLY_CORRECT" mode which still supports the features we
+        # use: subshells / arrays
+        if sys.platform == 'win32':  # pragma: win32 cover
+            hook_file.write('#!/bin/sh\n')
+
         hook_file.write(before + TEMPLATE_START)
         hook_file.write(f'INSTALL_PYTHON={shlex.quote(sys.executable)}\n')
         # TODO: python3.8+: shlex.join