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gh-112730: Use color to highlight error locations
Signed-off-by: Pablo Galindo <pablogsal@gmail.com>
1 parent c27b09c commit 9bc06ed

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6 files changed

+201
-27
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6 files changed

+201
-27
lines changed

‎Doc/using/cmdline.rst‎

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@@ -1110,6 +1110,12 @@ conflict.
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11111111
.. versionadded:: 3.13
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.. envvar:: PY_COLORS
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If this variable is set to ``1``, the interpreter will colorize different kinds
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of output. Setting it to ``0`` deactivates this behavior.
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.. versionadded:: 3.13
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Debug-mode variables
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~~~~~~~~~~~~~~~~~~~~

‎Doc/whatsnew/3.13.rst‎

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@@ -85,7 +85,13 @@ Important deprecations, removals or restrictions:
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New Features
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============
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Improved Error Messages
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-----------------------
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* The interpreter now colorizes error messages when displaying tracebacks by default.
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This feature can be controlled via the new :envvar:`PY_COLORS` environment variable
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as well as the canonical ``NO_COLOR`` and ``FORCE_COLOR`` environment variables.
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(Contributed by Pablo Galindo Salgado in :gh:`112730`.)
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Other Language Changes
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======================

‎Lib/test/test_traceback.py‎

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Original file line numberDiff line numberDiff line change
@@ -8,6 +8,7 @@
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import inspect
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import builtins
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import unittest
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import unittest.mock
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import re
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import tempfile
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import random
@@ -41,6 +42,14 @@
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class TracebackCases(unittest.TestCase):
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# For now, a very minimal set of tests. I want to be sure that
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# formatting of SyntaxErrors works based on changes for 2.1.
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def setUp(self):
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super().setUp()
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self.colorize = traceback._COLORIZE
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traceback._COLORIZE = False
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def tearDown(self):
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super().tearDown()
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traceback._COLORIZE = self.colorize
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def get_exception_format(self, func, exc):
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try:
@@ -521,7 +530,7 @@ def test_signatures(self):
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self.assertEqual(
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str(inspect.signature(traceback.print_exception)),
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('(exc, /, value=<implicit>, tb=<implicit>, '
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'limit=None, file=None, chain=True)'))
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'limit=None, file=None, chain=True, **kwargs)'))
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self.assertEqual(
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str(inspect.signature(traceback.format_exception)),
@@ -3031,7 +3040,7 @@ def some_inner(k, v):
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30323041
def test_custom_format_frame(self):
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class CustomStackSummary(traceback.StackSummary):
3034-
def format_frame_summary(self, frame_summary):
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def format_frame_summary(self, frame_summary, colorize=False):
30353044
return f'{frame_summary.filename}:{frame_summary.lineno}'
30363045

30373046
def some_inner():
@@ -3056,7 +3065,7 @@ def g():
30563065
tb = g()
30573066

30583067
class Skip_G(traceback.StackSummary):
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def format_frame_summary(self, frame_summary):
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def format_frame_summary(self, frame_summary, colorize=False):
30603069
if frame_summary.name == 'g':
30613070
return None
30623071
return super().format_frame_summary(frame_summary)
@@ -3076,7 +3085,6 @@ def __repr__(self) -> str:
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raise Exception("Unrepresentable")
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30783087
class TestTracebackException(unittest.TestCase):
3079-
30803088
def do_test_smoke(self, exc, expected_type_str):
30813089
try:
30823090
raise exc
@@ -4245,6 +4253,85 @@ def test_levenshtein_distance_short_circuit(self):
42454253
res3 = traceback._levenshtein_distance(a, b, threshold)
42464254
self.assertGreater(res3, threshold, msg=(a, b, threshold))
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4256+
class TestColorizedTraceback(unittest.TestCase):
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def test_colorized_traceback(self):
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def foo(*args):
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x = {'a':{'b': None}}
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y = x['a']['b']['c']
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def baz(*args):
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return foo(1,2,3,4)
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def bar():
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return baz(1,
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2,3
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,4)
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try:
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bar()
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except Exception as e:
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exc = traceback.TracebackException.from_exception(
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e, capture_locals=True
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)
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lines = "".join(exc.format(colorize=True))
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red = traceback._ANSIColors.RED
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boldr = traceback._ANSIColors.BOLD_RED
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reset = traceback._ANSIColors.RESET
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self.assertIn("y = " + red + "x['a']['b']" + reset + boldr + "['c']" + reset, lines)
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self.assertIn("return " + red + "foo" + reset + boldr + "(1,2,3,4)" + reset, lines)
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self.assertIn("return " + red + "baz" + reset + boldr + "(1," + reset, lines)
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self.assertIn(boldr + "2,3" + reset, lines)
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self.assertIn(boldr + ",4)" + reset, lines)
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self.assertIn(red + "bar" + reset + boldr + "()" + reset, lines)
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def test_colorized_traceback_is_the_default(self):
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def foo():
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1/0
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from _testcapi import exception_print
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try:
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foo()
4293+
self.fail("No exception thrown.")
4294+
except Exception as e:
4295+
with captured_output("stderr") as tbstderr:
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with unittest.mock.patch('traceback._can_colorize', return_value=True):
4297+
exception_print(e)
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actual = tbstderr.getvalue().splitlines()
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4300+
red = traceback._ANSIColors.RED
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boldr = traceback._ANSIColors.BOLD_RED
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reset = traceback._ANSIColors.RESET
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lno_foo = foo.__code__.co_firstlineno
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expected = ['Traceback (most recent call last):',
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f' File "{__file__}", '
4306+
f'line {lno_foo+5}, in test_colorized_traceback_is_the_default',
4307+
f' {red}foo{reset+boldr}(){reset}',
4308+
f' {red}~~~{reset+boldr}^^{reset}',
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f' File "{__file__}", '
4310+
f'line {lno_foo+1}, in foo',
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f' {red}1{reset+boldr}/{reset+red}0{reset}',
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f' {red}~{reset+boldr}^{reset+red}~{reset}',
4313+
'ZeroDivisionError: division by zero']
4314+
self.assertEqual(actual, expected)
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4316+
def test_colorized_detection_checks_for_environment_variables(self):
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with unittest.mock.patch("sys.stderr") as stderr_mock:
4318+
stderr_mock.isatty.return_value = True
4319+
with unittest.mock.patch("os.environ", {'TERM': 'dumb'}):
4320+
self.assertEqual(traceback._can_colorize(), False)
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with unittest.mock.patch("os.environ", {'PY_COLORS': '1'}):
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self.assertEqual(traceback._can_colorize(), True)
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with unittest.mock.patch("os.environ", {'PY_COLORS': '0'}):
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self.assertEqual(traceback._can_colorize(), False)
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with unittest.mock.patch("os.environ", {'NO_COLOR': '1'}):
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self.assertEqual(traceback._can_colorize(), False)
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with unittest.mock.patch("os.environ", {'NO_COLOR': '1', "PY_COLORS": '1'}):
4328+
self.assertEqual(traceback._can_colorize(), True)
4329+
with unittest.mock.patch("os.environ", {'FORCE_COLOR': '1'}):
4330+
self.assertEqual(traceback._can_colorize(), True)
4331+
with unittest.mock.patch("os.environ", {'FORCE_COLOR': '1', 'NO_COLOR': '1'}):
4332+
self.assertEqual(traceback._can_colorize(), False)
4333+
stderr_mock.isatty.return_value = False
4334+
self.assertEqual(traceback._can_colorize(), False)
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42494336
if __name__ == "__main__":
42504337
unittest.main()

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