Color support (#1630)

5 files changed, 53 insertions, 14 deletions

diff --git a/src/tox/config/cli/parse.py b/src/tox/config/cli/parse.py
index a31a01f6..5ba8c5f1 100644
--- a/src/tox/config/cli/parse.py
+++ b/src/tox/config/cli/parse.py
@@ -9,7 +9,7 @@ def get_options(*args) -> Tuple[Parsed, List[str], Dict[str, Handler]]:
     guess_verbosity = _get_base(args)
     handlers, parsed, unknown = _get_core(args)
     if guess_verbosity != parsed.verbosity:
-        setup_report(parsed.verbosity)  # pragma: no cover
+        setup_report(parsed.verbosity, parsed.is_colored)  # pragma: no cover
     return parsed, unknown, handlers
 
 
@@ -17,7 +17,7 @@ def _get_base(args):
     tox_parser = ToxParser.base()
     parsed, unknown = tox_parser.parse(args)
     guess_verbosity = parsed.verbosity
-    setup_report(guess_verbosity)
+    setup_report(guess_verbosity, parsed.is_colored)
     return guess_verbosity
 
 
diff --git a/src/tox/config/cli/parser.py b/src/tox/config/cli/parser.py
index 19cd3be4..4fff9c84 100644
--- a/src/tox/config/cli/parser.py
+++ b/src/tox/config/cli/parser.py
@@ -1,9 +1,12 @@
 import argparse
 import logging
+import os
+import sys
 from argparse import SUPPRESS, Action, ArgumentDefaultsHelpFormatter, ArgumentParser, Namespace
 from itertools import chain
 from typing import Any, Callable, Dict, List, Optional, Sequence, Tuple, Type, TypeVar
 
+from tox.config.source.ini import StrConvert
 from tox.plugin.util import NAME
 from tox.session.state import State
 
@@ -42,8 +45,16 @@ class ArgumentParserWithEnvAndConfig(ArgumentParser):
     def get_type(action):
         of_type = getattr(action, "of_type", None)
         if of_type is None:
-            # noinspection PyProtectedMember
-            if action.default is not None:
+            if isinstance(action, argparse._StoreAction) and action.choices:  # noqa
+                loc = locals()
+                if sys.version_info >= (3, 8):
+                    from typing import Literal  # noqa
+                else:
+                    from typing_extensions import Literal  # noqa
+                loc["Literal"] = Literal
+                as_literal = f"Literal[{', '.join(repr(i) for i in action.choices)}]"
+                of_type = eval(as_literal, globals(), loc)
+            elif action.default is not None:
                 of_type = type(action.default)
             elif isinstance(action, argparse._StoreConstAction) and action.const is not None:  # noqa
                 of_type = type(action.const)
@@ -71,6 +82,10 @@ class Parsed(Namespace):
     def verbosity(self) -> int:
         return max(self.verbose - self.quiet, 0)
 
+    @property
+    def is_colored(self) -> True:
+        return self.colored == "yes"
+
 
 Handler = Callable[[State], Optional[int]]
 
@@ -121,12 +136,20 @@ class ToxParser(ArgumentParserWithEnvAndConfig):
         verbosity_group = self.add_argument_group(
             f"verbosity=verbose-quiet, default {logging.getLevelName(LEVELS[3])}, map {level_map}",
         )
-        verbosity_exclusive = verbosity_group.add_mutually_exclusive_group()
-        verbosity_exclusive.add_argument(
-            "-v", "--verbose", action="count", dest="verbose", help="increase verbosity", default=2,
-        )
-        verbosity_exclusive.add_argument(
-            "-q", "--quiet", action="count", dest="quiet", help="decrease verbosity", default=0,
+        verbosity = verbosity_group.add_mutually_exclusive_group()
+        verbosity.add_argument("-v", "--verbose", action="count", dest="verbose", help="increase verbosity", default=2)
+        verbosity.add_argument("-q", "--quiet", action="count", dest="quiet", help="decrease verbosity", default=0)
+
+        converter = StrConvert()
+        if converter.to_bool(os.environ.get("NO_COLOR", "")):
+            color = "no"
+        elif converter.to_bool(os.environ.get("FORCE_COLOR", "")):
+            color = "yes"
+        else:
+            color = "yes" if sys.stdout.isatty() else "no"
+
+        verbosity_group.add_argument(
+            "--colored", default=color, choices=["yes", "no"], help="should output be enriched with colors",
         )
         self.fix_defaults()
 
diff --git a/src/tox/config/source/api.py b/src/tox/config/source/api.py
index d548f16c..7d8405a8 100644
--- a/src/tox/config/source/api.py
+++ b/src/tox/config/source/api.py
@@ -1,3 +1,4 @@
+import sys
 from abc import ABC, abstractmethod
 from collections import OrderedDict
 from pathlib import Path
@@ -5,6 +6,11 @@ from typing import Any, Dict, List, Sequence, Set, Union
 
 from tox.execute.request import shell_cmd
 
+if sys.version_info >= (3, 8):
+    from typing import Literal
+else:
+    from typing_extensions import Literal
+
 _NO_MAPPING = object()
 
 
@@ -39,7 +45,8 @@ class EnvList:
 
 class Convert(ABC):
     def to(self, raw, of_type):
-        if getattr(of_type, "__module__", None) == "typing":
+        from_module = getattr(of_type, "__module__", None)
+        if from_module in ("typing", "typing_extensions"):
             return self._to_typing(raw, of_type)
         elif issubclass(of_type, Path):
             return self.to_path(raw)
@@ -54,7 +61,7 @@ class Convert(ABC):
         return of_type(raw)
 
     def _to_typing(self, raw, of_type):
-        origin = getattr(of_type, "__origin__", None)
+        origin = getattr(of_type, "__origin__", getattr(of_type, "__class__", None))
         if origin is not None:
             result = _NO_MAPPING  # type: Any
             if origin in (list, List):
@@ -72,6 +79,14 @@ class Convert(ABC):
                     else:
                         new_type = next(i for i in of_type.__args__ if i != type(None))  # noqa
                         result = self._to_typing(raw, new_type)
+            elif origin == Literal or origin == type(Literal):
+                if sys.version_info >= (3, 7):
+                    choice = of_type.__args__
+                else:
+                    choice = of_type.__values__
+                if raw not in choice:
+                    raise ValueError(f"{raw} must be one of {choice}")
+                result = raw
             if result is not _NO_MAPPING:
                 return result
         raise TypeError(f"{raw} cannot cast to {of_type!r}")
diff --git a/src/tox/config/source/ini/__init__.py b/src/tox/config/source/ini/__init__.py
index e1cd135a..9ec14e6f 100644
--- a/src/tox/config/source/ini/__init__.py
+++ b/src/tox/config/source/ini/__init__.py
@@ -170,7 +170,7 @@ class IniLoader(StrConvert, Loader):
         if self._section is None:
             raise KeyError(key)
         value = self._section[key]
-        collapsed_newlines = value.replace("\\\n", "")  # collapse explicit line splits
+        collapsed_newlines = value.replace("\\\r", "").replace("\\\n", "")  # collapse explicit line splits
         replace_executed = replace(collapsed_newlines, conf, as_name, self._section_loader)  # do replacements
         factor_selected = filter_for_env(replace_executed, as_name)  # select matching factors
         # extend factors
diff --git a/src/tox/config/source/ini/convert.py b/src/tox/config/source/ini/convert.py
index 7e0b002e..155365a9 100644
--- a/src/tox/config/source/ini/convert.py
+++ b/src/tox/config/source/ini/convert.py
@@ -13,6 +13,7 @@ class StrConvert(Convert):
     @staticmethod
     def to_list(value):
         splitter = "\n" if "\n" in value else ","
+        splitter = splitter.replace("\r", "")
         for token in value.split(splitter):
             value = token.strip()
             if value:
@@ -48,7 +49,7 @@ class StrConvert(Convert):
         return EnvList(elements)
 
     TRUTHFUL_VALUES = {"true", "1", "yes", "on"}
-    FALSY_VALUES = {"false", "0", "no", "off"}
+    FALSY_VALUES = {"false", "0", "no", "off", ""}
     VALID_BOOL = list(sorted(TRUTHFUL_VALUES | FALSY_VALUES))
 
     @staticmethod