default to color and only wrap lines if there is a terminal

Author: KotlinIsland

.github/workflows/test.yml

@@ -109,10 +109,6 @@ jobs:
       FORCE_COLOR: 1
       # Tox
       PY_COLORS: 1
-      # Mypy (see https://github.com/python/mypy/issues/7771)
-      TERM: xterm-color
-      MYPY_FORCE_COLOR: 1
-      MYPY_FORCE_TERMINAL_WIDTH: 200
       # Pytest
       PYTEST_ADDOPTS: --color=yes
     steps:

CHANGELOG.md

@@ -3,6 +3,9 @@
 ## [Unreleased]
 ### Enhancements
 - Show 'narrowed from' in `reveal_type` (#550)
+- `--color-output` is enabled by default (#531)
+- `--ide` will disable color-output (#531)
+- Output lines won't wrap if not connected to a terminal (#531)
 ### Fixes
 - Render star args in error messages properly (#551)
 

mypy/build.py

@@ -1103,7 +1103,9 @@ def load_baseline(options: Options, errors: Errors, stdout: TextIO) -> None:
 
     from mypy import main
 
-    formatter = util.FancyFormatter(stdout, stderr, options.hide_error_codes)
+    formatter = util.FancyFormatter(
+        stdout, stderr, options.hide_error_codes, color=options.color_output
+    )
     file = Path(options.baseline_file)
 
     if not file.exists():

mypy/main.py

@@ -72,7 +72,9 @@ def main(
     if clean_exit:
         options.fast_exit = False
 
-    formatter = util.FancyFormatter(stdout, stderr, options.hide_error_codes)
+    formatter = util.FancyFormatter(
+        stdout, stderr, options.hide_error_codes, color=options.color_output
+    )
 
     if options.install_types and (stdout is not sys.stdout or stderr is not sys.stderr):
         # Since --install-types performs user input, we want regular stdout and stderr.
@@ -1362,6 +1364,7 @@ def set_ide_flags() -> None:
             "error_summary": False,
             "pretty": False,
             "show_error_end": True,
+            "color_output": False,
         }.items():
             setattr(options, dest, value)
 

mypy/test/testcmdline.py

@@ -71,6 +71,7 @@ def test_python_cmdline(testcase: DataDrivenTestCase, step: int) -> None:
         args.append("--no-default-return")
     if "--pretty" not in args:
         args.append("--no-pretty")
+    args.append("--no-color-output")
     if "--show-error-code-links" not in args and "--ide" not in args:
         args.append("--hide-error-code-links")
     if "--error-summary" not in args:
@@ -90,6 +91,8 @@ def test_python_cmdline(testcase: DataDrivenTestCase, step: int) -> None:
     extra_path = os.path.join(os.path.abspath(test_temp_dir), "pypath")
     env["PYTHONPATH"] = PREFIX
     env["__MYPY_UNDER_TEST__"] = "1" if based else "2"
+    if "--pretty" in args:
+        env["COLUMNS"] = "80"
     if os.path.isdir(extra_path):
         env["PYTHONPATH"] += os.pathsep + extra_path
     cwd = os.path.join(test_temp_dir, custom_cwd or "")

mypy/test/testpep561.py

@@ -133,6 +133,7 @@ def test_pep561(testcase: DataDrivenTestCase) -> None:
                 "--no-strict",
                 "--no-pretty",
                 "--hide-error-context",
+                "--no-color-output",
             ]
         )
         if python_executable != sys.executable:

mypy/test/testpythoneval.py

@@ -85,6 +85,7 @@ def test_python_evaluation(testcase: DataDrivenTestCase, cache_dir: str) -> None
         for s in testcase.input:
             file.write(f"{s}\n")
     mypy_cmdline.append(f"--cache-dir={cache_dir}")
+    mypy_cmdline.append("--no-color-output")
     output = []
     # Type check the program.
     out, err, returncode = api.run(mypy_cmdline)

mypy/util.py

@@ -522,13 +522,14 @@ class FancyFormatter:
     This currently only works on Linux and Mac.
     """
 
-    def __init__(self, f_out: IO[str], f_err: IO[str], hide_error_codes: bool) -> None:
+    def __init__(self, f_out: IO[str], f_err: IO[str], hide_error_codes: bool, color=True) -> None:
         self.hide_error_codes = hide_error_codes
         # Check if we are in a human-facing terminal on a supported platform.
         if sys.platform not in ("linux", "darwin", "win32", "emscripten"):
             self.dummy_term = True
             return
-        if not should_force_color() and (not f_out.isatty() or not f_err.isatty()):
+        # TODO: handle NO_COLOR and FORCE_COLOR
+        if not color:
             self.dummy_term = True
             return
         if sys.platform == "win32":
@@ -652,6 +653,12 @@ def fit_in_terminal(
         self, messages: list[str], fixed_terminal_width: int | None = None
     ) -> list[str]:
         """Improve readability by wrapping error messages and trimming source code."""
+        if not os.environ.get("COLUMNS"):
+            # Only wrap if there is actually a terminal
+            try:
+                os.get_terminal_size(sys.__stdout__.fileno())
+            except (AttributeError, ValueError, OSError):
+                return messages
         width = fixed_terminal_width or get_terminal_width()
         new_messages = messages.copy()
         for i, error in enumerate(messages):

test-data/unit/daemon.test

@@ -282,7 +282,7 @@ def foo():
 [case testDaemonQuickstart]
 $ {python} -c "print('x=1')" >foo.py
 $ {python} -c "print('x=1')" >bar.py
-$ mypy --no-nonlocal-partial-types --cache-fine-grained --follow-imports=error --no-sqlite-cache --python-version=3.11 -- foo.py bar.py
+$ mypy --no-nonlocal-partial-types --cache-fine-grained --follow-imports=error --no-sqlite-cache --python-version=3.11 --no-color-output -- foo.py bar.py
 Success: no issues found in 2 source files
 $ {python} -c "import shutil; shutil.copy('.mypy_cache/3.11/bar.meta.json', 'asdf.json')"
 -- update bar's timestamp but don't change the file

tox.ini

@@ -48,10 +48,6 @@ commands = pre-commit run --all-files --show-diff-on-failure
 
 [testenv:type]
 description = type check ourselves
-passenv =
-    TERM
-    MYPY_FORCE_COLOR
-    MYPY_FORCE_TERMINAL_WIDTH
 commands =
     python runtests.py self
     # Do a no-strict compatible check, this is needed because generating a baseline from the head of upstream