Merge pull request #1382 from pre-commit/better_windows_color

asottile · web-flow · commit 30a36a8a006c · 2020-04-02T07:48:17.000-07:00
support colors on windows during git better
diff --git a/pre_commit/color.py b/pre_commit/color.py
@@ -11,7 +11,7 @@ def _enable() -> None:
         from ctypes.wintypes import DWORD
         from ctypes.wintypes import HANDLE
 
-        STD_OUTPUT_HANDLE = -11
+        STD_ERROR_HANDLE = -12
         ENABLE_VIRTUAL_TERMINAL_PROCESSING = 4
 
         def bool_errcheck(result, func, args):
@@ -40,9 +40,9 @@ def bool_errcheck(result, func, args):
         #
         # More info on the escape sequences supported:
         # https://msdn.microsoft.com/en-us/library/windows/desktop/mt638032(v=vs.85).aspx
-        stdout = GetStdHandle(STD_OUTPUT_HANDLE)
-        flags = GetConsoleMode(stdout)
-        SetConsoleMode(stdout, flags | ENABLE_VIRTUAL_TERMINAL_PROCESSING)
+        stderr = GetStdHandle(STD_ERROR_HANDLE)
+        flags = GetConsoleMode(stderr)
+        SetConsoleMode(stderr, flags | ENABLE_VIRTUAL_TERMINAL_PROCESSING)
 
     try:
         _enable()
@@ -90,7 +90,7 @@ def use_color(setting: str) -> bool:
     return (
         setting == 'always' or (
             setting == 'auto' and
-            sys.stdout.isatty() and
+            sys.stderr.isatty() and
             terminal_supports_color and
             os.getenv('TERM') != 'dumb'
         )
diff --git a/tests/color_test.py b/tests/color_test.py
@@ -29,26 +29,26 @@ def test_use_color_always():
 
 
 def test_use_color_no_tty():
-    with mock.patch.object(sys.stdout, 'isatty', return_value=False):
+    with mock.patch.object(sys.stderr, 'isatty', return_value=False):
         assert use_color('auto') is False
 
 
 def test_use_color_tty_with_color_support():
-    with mock.patch.object(sys.stdout, 'isatty', return_value=True):
+    with mock.patch.object(sys.stderr, 'isatty', return_value=True):
         with mock.patch('pre_commit.color.terminal_supports_color', True):
             with envcontext.envcontext((('TERM', envcontext.UNSET),)):
                 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.object(sys.stderr, 'isatty', return_value=True):
         with mock.patch('pre_commit.color.terminal_supports_color', False):
             with envcontext.envcontext((('TERM', envcontext.UNSET),)):
                 assert use_color('auto') is False
 
 
 def test_use_color_dumb_term():
-    with mock.patch.object(sys.stdout, 'isatty', return_value=True):
+    with mock.patch.object(sys.stderr, 'isatty', return_value=True):
         with mock.patch('pre_commit.color.terminal_supports_color', True):
             with envcontext.envcontext((('TERM', 'dumb'),)):
                 assert use_color('auto') is False
