fix: improve correctness of exits (#539)

* fix: improve correctness of exits

* refactor: use sys.exit

bin/bump_version.py

@@ -1,8 +1,10 @@
 #!/usr/bin/env python3
 
+
 import glob
 import os
 import subprocess
+import sys
 import urllib.parse
 from pathlib import Path
 
@@ -23,6 +25,8 @@ config = [
 ]
 
 
+# This file requires Python 3.7
+# Setting -> None will cause MyPy to notice this.
 @click.command()
 def bump_version():
     current_version = cibuildwheel.__version__
@@ -49,7 +53,7 @@ def bump_version():
 
     if repo_has_uncommitted_changes:
         print('error: Uncommitted changes detected.')
-        exit(1)
+        sys.exit(1)
 
     print(              'Current version:', current_version)  # noqa
     new_version = input('    New version: ').strip()
@@ -59,7 +63,7 @@ def bump_version():
     except InvalidVersion:
         print("error: This version doesn't conform to PEP440")
         print('       https://www.python.org/dev/peps/pep-0440/')
-        exit(1)
+        sys.exit(1)
 
     actions = []
 
@@ -68,7 +72,7 @@ def bump_version():
 
         if not paths:
             print(f'error: Pattern {path_pattern} didn’t match any files')
-            exit(1)
+            sys.exit(1)
 
         find_pattern = version_pattern.format(current_version)
         replace_pattern = version_pattern.format(new_version)
@@ -83,8 +87,8 @@ def bump_version():
                 )
 
         if not found_at_least_one_file_needing_update:
-            print(f'error: Didn’t find any occurences of “{find_pattern}” in “{path_pattern}”')
-            exit(1)
+            print(f'error: Didn’t find any occurrences of “{find_pattern}” in “{path_pattern}”')
+            sys.exit(1)
 
     print()
     print("Here's the plan:")
@@ -102,7 +106,7 @@ def bump_version():
 
     if answer != 'y':
         print('Aborted')
-        exit(1)
+        sys.exit(1)
 
     for path, find, replace in actions:
         contents = path.read_text(encoding='utf8')