Merge pull request #819 from jeffreyrack/fix-windows-reporting

Don't print bogus characters on windows terminals that don't support colors

pre_commit/color.py

@@ -3,12 +3,13 @@ from __future__ import unicode_literals
 import os
 import sys
 
+terminal_supports_color = True
 if os.name == 'nt':  # pragma: no cover (windows)
     from pre_commit.color_windows import enable_virtual_terminal_processing
     try:
         enable_virtual_terminal_processing()
     except WindowsError:
-        pass
+        terminal_supports_color = False
 
 RED = '\033[41m'
 GREEN = '\033[42m'
@@ -47,4 +48,7 @@ def use_color(setting):
     if setting not in COLOR_CHOICES:
         raise InvalidColorSetting(setting)
 
-    return setting == 'always' or (setting == 'auto' and sys.stdout.isatty())
+    return (
+        setting == 'always' or
+        (setting == 'auto' and sys.stdout.isatty() and terminal_supports_color)
+    )

tests/color_test.py

@@ -35,9 +35,16 @@ def test_use_color_no_tty():
         assert use_color('auto') is False
 
 
-def test_use_color_tty():
+def test_use_color_tty_with_color_support():
     with mock.patch.object(sys.stdout, 'isatty', return_value=True):
-        assert use_color('auto') is True
+        with mock.patch('pre_commit.color.terminal_supports_color', True):
+            assert use_color('auto') is True
+
+
+def test_use_color_tty_without_color_support():
+    with mock.patch.object(sys.stdout, 'isatty', return_value=True):
+        with mock.patch('pre_commit.color.terminal_supports_color', False):
+            assert use_color('auto') is False
 
 
 def test_use_color_raises_if_given_shenanigans():