Init colorama only in Windows legacy terminal

knack/cli.py

@@ -11,7 +11,7 @@
 from .completion import CLICompletion
 from .output import OutputProducer
 from .log import CLILogging, get_logger
-from .util import CLIError
+from .util import CLIError, is_modern_terminal
 from .config import CLIConfig
 from .query import CLIQuery
 from .events import EVENT_CLI_PRE_EXECUTE, EVENT_CLI_SUCCESSFUL_EXECUTE, EVENT_CLI_POST_EXECUTE
@@ -101,6 +101,8 @@ def __init__(self,
 
         self.only_show_errors = self.config.getboolean('core', 'only_show_errors', fallback=False)
         self.enable_color = self._should_enable_color()
+        # Init colorama only in Windows legacy terminal
+        self._should_init_colorama = self.enable_color and os.name == 'nt' and not is_modern_terminal()
 
     @staticmethod
     def _should_show_version(args):
@@ -207,7 +209,8 @@ def invoke(self, args, initial_invocation_data=None, out_file=None):
         exit_code = 0
         try:
             out_file = out_file or self.out_file
-            if out_file is sys.stdout and self.enable_color or _KNACK_TEST_FORCE_ENABLE_COLOR:
+            if out_file is sys.stdout and self._should_init_colorama or _KNACK_TEST_FORCE_ENABLE_COLOR:
+                self.init_debug_log.append("Init colorama.")
                 import colorama
                 colorama.init()
                 # point out_file to the new sys.stdout which is overwritten by colorama
@@ -250,7 +253,7 @@ def invoke(self, args, initial_invocation_data=None, out_file=None):
         finally:
             self.raise_event(EVENT_CLI_POST_EXECUTE)
 
-            if self.enable_color or _KNACK_TEST_FORCE_ENABLE_COLOR:
+            if self._should_init_colorama or _KNACK_TEST_FORCE_ENABLE_COLOR:
                 import colorama
                 colorama.deinit()
 
@@ -274,14 +277,13 @@ def _should_enable_color(self):
             self.init_debug_log.append("Color is disabled by config.")
             return False
 
-        if 'PYCHARM_HOSTED' in os.environ:
-            if sys.stdout == sys.__stdout__ and sys.stderr == sys.__stderr__:
-                self.init_debug_log.append("Enable color in PyCharm.")
-                return True
-        else:
-            if sys.stdout.isatty() and sys.stderr.isatty() and self.out_file is sys.stdout:
-                self.init_debug_log.append("Enable color in terminal.")
-                return True
+        if sys.stdout.isatty() and sys.stderr.isatty() and self.out_file is sys.stdout:
+            self.init_debug_log.append("Enable color in terminal.")
+            return True
+
+        if 'PYCHARM_HOSTED' in os.environ and sys.stdout == sys.__stdout__ and sys.stderr == sys.__stderr__:
+            self.init_debug_log.append("Enable color in PyCharm.")
+            return True
 
         self.init_debug_log.append("Cannot enable color.")
         return False

knack/util.py

@@ -142,3 +142,24 @@ def todict(obj, post_processor=None):  # pylint: disable=too-many-return-stateme
                   if not callable(v) and not k.startswith('_')}
         return post_processor(obj, result) if post_processor else result
     return obj
+
+
+def is_modern_terminal():
+    """Detect whether the current terminal is a modern terminal that supports Unicode and
+    Console Virtual Terminal Sequences.
+
+    Currently, these terminals can be detected:
+      - VS Code terminal
+      - PyCharm
+      - Windows Terminal
+    """
+    # VS Code: https://github.com/microsoft/vscode/pull/30346
+    if os.environ.get('TERM_PROGRAM', '').lower() == 'vscode':
+        return True
+    # PyCharm: https://youtrack.jetbrains.com/issue/PY-4853
+    if 'PYCHARM_HOSTED' in os.environ:
+        return True
+    # Windows Terminal: https://github.com/microsoft/terminal/issues/1040
+    if 'WT_SESSION' in os.environ:
+        return True
+    return False

tests/test_util.py

@@ -3,11 +3,12 @@
 # Licensed under the MIT License. See License.txt in the project root for license information.
 # --------------------------------------------------------------------------------------------
 
-from collections import namedtuple
 import unittest
+from collections import namedtuple
 from datetime import date, time, datetime
+from unittest import mock
 
-from knack.util import todict, to_snake_case
+from knack.util import todict, to_snake_case, is_modern_terminal
 
 
 class TestUtils(unittest.TestCase):
@@ -87,6 +88,16 @@ def test_to_snake_case_already_snake(self):
         actual = to_snake_case(the_input)
         self.assertEqual(expected, actual)
 
+    def test_is_modern_terminal(self):
+        with mock.patch.dict("os.environ", clear=True):
+            self.assertEqual(is_modern_terminal(), False)
+        with mock.patch.dict("os.environ", TERM_PROGRAM='vscode'):
+            self.assertEqual(is_modern_terminal(), True)
+        with mock.patch.dict("os.environ", PYCHARM_HOSTED='1'):
+            self.assertEqual(is_modern_terminal(), True)
+        with mock.patch.dict("os.environ", WT_SESSION='c25cb945-246a-49e5-b37a-1e4b6671b916'):
+            self.assertEqual(is_modern_terminal(), True)
+
 
 if __name__ == '__main__':
     unittest.main()