cpython/Lib/test/test_traceback.py

740 lines
27 KiB
Python

"""Test cases for traceback module"""
from collections import namedtuple
from io import StringIO
import linecache
import sys
import unittest
import re
from test.support import run_unittest, Error, captured_output
from test.support import TESTFN, unlink, cpython_only
from test.script_helper import assert_python_ok
import textwrap
import traceback
test_code = namedtuple('code', ['co_filename', 'co_name'])
test_frame = namedtuple('frame', ['f_code', 'f_globals', 'f_locals'])
test_tb = namedtuple('tb', ['tb_frame', 'tb_lineno', 'tb_next'])
class SyntaxTracebackCases(unittest.TestCase):
# For now, a very minimal set of tests. I want to be sure that
# formatting of SyntaxErrors works based on changes for 2.1.
def get_exception_format(self, func, exc):
try:
func()
except exc as value:
return traceback.format_exception_only(exc, value)
else:
raise ValueError("call did not raise exception")
def syntax_error_with_caret(self):
compile("def fact(x):\n\treturn x!\n", "?", "exec")
def syntax_error_with_caret_2(self):
compile("1 +\n", "?", "exec")
def syntax_error_bad_indentation(self):
compile("def spam():\n print(1)\n print(2)", "?", "exec")
def syntax_error_with_caret_non_ascii(self):
compile('Python = "\u1e54\xfd\u0163\u0125\xf2\xf1" +', "?", "exec")
def syntax_error_bad_indentation2(self):
compile(" print(2)", "?", "exec")
def test_caret(self):
err = self.get_exception_format(self.syntax_error_with_caret,
SyntaxError)
self.assertEqual(len(err), 4)
self.assertTrue(err[1].strip() == "return x!")
self.assertIn("^", err[2]) # third line has caret
self.assertEqual(err[1].find("!"), err[2].find("^")) # in the right place
err = self.get_exception_format(self.syntax_error_with_caret_2,
SyntaxError)
self.assertIn("^", err[2]) # third line has caret
self.assertEqual(err[2].count('\n'), 1) # and no additional newline
self.assertEqual(err[1].find("+"), err[2].find("^")) # in the right place
err = self.get_exception_format(self.syntax_error_with_caret_non_ascii,
SyntaxError)
self.assertIn("^", err[2]) # third line has caret
self.assertEqual(err[2].count('\n'), 1) # and no additional newline
self.assertEqual(err[1].find("+"), err[2].find("^")) # in the right place
def test_nocaret(self):
exc = SyntaxError("error", ("x.py", 23, None, "bad syntax"))
err = traceback.format_exception_only(SyntaxError, exc)
self.assertEqual(len(err), 3)
self.assertEqual(err[1].strip(), "bad syntax")
def test_bad_indentation(self):
err = self.get_exception_format(self.syntax_error_bad_indentation,
IndentationError)
self.assertEqual(len(err), 4)
self.assertEqual(err[1].strip(), "print(2)")
self.assertIn("^", err[2])
self.assertEqual(err[1].find(")"), err[2].find("^"))
err = self.get_exception_format(self.syntax_error_bad_indentation2,
IndentationError)
self.assertEqual(len(err), 4)
self.assertEqual(err[1].strip(), "print(2)")
self.assertIn("^", err[2])
self.assertEqual(err[1].find("p"), err[2].find("^"))
def test_base_exception(self):
# Test that exceptions derived from BaseException are formatted right
e = KeyboardInterrupt()
lst = traceback.format_exception_only(e.__class__, e)
self.assertEqual(lst, ['KeyboardInterrupt\n'])
def test_format_exception_only_bad__str__(self):
class X(Exception):
def __str__(self):
1/0
err = traceback.format_exception_only(X, X())
self.assertEqual(len(err), 1)
str_value = '<unprintable %s object>' % X.__name__
if X.__module__ in ('__main__', 'builtins'):
str_name = X.__qualname__
else:
str_name = '.'.join([X.__module__, X.__qualname__])
self.assertEqual(err[0], "%s: %s\n" % (str_name, str_value))
def test_without_exception(self):
err = traceback.format_exception_only(None, None)
self.assertEqual(err, ['None\n'])
def test_encoded_file(self):
# Test that tracebacks are correctly printed for encoded source files:
# - correct line number (Issue2384)
# - respect file encoding (Issue3975)
import tempfile, sys, subprocess, os
# The spawned subprocess has its stdout redirected to a PIPE, and its
# encoding may be different from the current interpreter, on Windows
# at least.
process = subprocess.Popen([sys.executable, "-c",
"import sys; print(sys.stdout.encoding)"],
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
stdout, stderr = process.communicate()
output_encoding = str(stdout, 'ascii').splitlines()[0]
def do_test(firstlines, message, charset, lineno):
# Raise the message in a subprocess, and catch the output
try:
output = open(TESTFN, "w", encoding=charset)
output.write("""{0}if 1:
import traceback;
raise RuntimeError('{1}')
""".format(firstlines, message))
output.close()
process = subprocess.Popen([sys.executable, TESTFN],
stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
stdout, stderr = process.communicate()
stdout = stdout.decode(output_encoding).splitlines()
finally:
unlink(TESTFN)
# The source lines are encoded with the 'backslashreplace' handler
encoded_message = message.encode(output_encoding,
'backslashreplace')
# and we just decoded them with the output_encoding.
message_ascii = encoded_message.decode(output_encoding)
err_line = "raise RuntimeError('{0}')".format(message_ascii)
err_msg = "RuntimeError: {0}".format(message_ascii)
self.assertIn(("line %s" % lineno), stdout[1],
"Invalid line number: {0!r} instead of {1}".format(
stdout[1], lineno))
self.assertTrue(stdout[2].endswith(err_line),
"Invalid traceback line: {0!r} instead of {1!r}".format(
stdout[2], err_line))
self.assertTrue(stdout[3] == err_msg,
"Invalid error message: {0!r} instead of {1!r}".format(
stdout[3], err_msg))
do_test("", "foo", "ascii", 3)
for charset in ("ascii", "iso-8859-1", "utf-8", "GBK"):
if charset == "ascii":
text = "foo"
elif charset == "GBK":
text = "\u4E02\u5100"
else:
text = "h\xe9 ho"
do_test("# coding: {0}\n".format(charset),
text, charset, 4)
do_test("#!shebang\n# coding: {0}\n".format(charset),
text, charset, 5)
do_test(" \t\f\n# coding: {0}\n".format(charset),
text, charset, 5)
# Issue #18960: coding spec should has no effect
do_test("0\n# coding: GBK\n", "h\xe9 ho", 'utf-8', 5)
def test_print_traceback_at_exit(self):
# Issue #22599: Ensure that it is possible to use the traceback module
# to display an exception at Python exit
code = textwrap.dedent("""
import sys
import traceback
class PrintExceptionAtExit(object):
def __init__(self):
try:
x = 1 / 0
except Exception:
self.exc_info = sys.exc_info()
# self.exc_info[1] (traceback) contains frames:
# explicitly clear the reference to self in the current
# frame to break a reference cycle
self = None
def __del__(self):
traceback.print_exception(*self.exc_info)
# Keep a reference in the module namespace to call the destructor
# when the module is unloaded
obj = PrintExceptionAtExit()
""")
rc, stdout, stderr = assert_python_ok('-c', code)
expected = [b'Traceback (most recent call last):',
b' File "<string>", line 8, in __init__',
b'ZeroDivisionError: division by zero']
self.assertEqual(stderr.splitlines(), expected)
class TracebackFormatTests(unittest.TestCase):
def some_exception(self):
raise KeyError('blah')
@cpython_only
def check_traceback_format(self, cleanup_func=None):
from _testcapi import traceback_print
try:
self.some_exception()
except KeyError:
type_, value, tb = sys.exc_info()
if cleanup_func is not None:
# Clear the inner frames, not this one
cleanup_func(tb.tb_next)
traceback_fmt = 'Traceback (most recent call last):\n' + \
''.join(traceback.format_tb(tb))
file_ = StringIO()
traceback_print(tb, file_)
python_fmt = file_.getvalue()
# Call all _tb and _exc functions
with captured_output("stderr") as tbstderr:
traceback.print_tb(tb)
tbfile = StringIO()
traceback.print_tb(tb, file=tbfile)
with captured_output("stderr") as excstderr:
traceback.print_exc()
excfmt = traceback.format_exc()
excfile = StringIO()
traceback.print_exc(file=excfile)
else:
raise Error("unable to create test traceback string")
# Make sure that Python and the traceback module format the same thing
self.assertEqual(traceback_fmt, python_fmt)
# Now verify the _tb func output
self.assertEqual(tbstderr.getvalue(), tbfile.getvalue())
# Now verify the _exc func output
self.assertEqual(excstderr.getvalue(), excfile.getvalue())
self.assertEqual(excfmt, excfile.getvalue())
# Make sure that the traceback is properly indented.
tb_lines = python_fmt.splitlines()
self.assertEqual(len(tb_lines), 5)
banner = tb_lines[0]
location, source_line = tb_lines[-2:]
self.assertTrue(banner.startswith('Traceback'))
self.assertTrue(location.startswith(' File'))
self.assertTrue(source_line.startswith(' raise'))
def test_traceback_format(self):
self.check_traceback_format()
def test_traceback_format_with_cleared_frames(self):
# Check that traceback formatting also works with a clear()ed frame
def cleanup_tb(tb):
tb.tb_frame.clear()
self.check_traceback_format(cleanup_tb)
def test_stack_format(self):
# Verify _stack functions. Note we have to use _getframe(1) to
# compare them without this frame appearing in the output
with captured_output("stderr") as ststderr:
traceback.print_stack(sys._getframe(1))
stfile = StringIO()
traceback.print_stack(sys._getframe(1), file=stfile)
self.assertEqual(ststderr.getvalue(), stfile.getvalue())
stfmt = traceback.format_stack(sys._getframe(1))
self.assertEqual(ststderr.getvalue(), "".join(stfmt))
cause_message = (
"\nThe above exception was the direct cause "
"of the following exception:\n\n")
context_message = (
"\nDuring handling of the above exception, "
"another exception occurred:\n\n")
boundaries = re.compile(
'(%s|%s)' % (re.escape(cause_message), re.escape(context_message)))
class BaseExceptionReportingTests:
def get_exception(self, exception_or_callable):
if isinstance(exception_or_callable, Exception):
return exception_or_callable
try:
exception_or_callable()
except Exception as e:
return e
def zero_div(self):
1/0 # In zero_div
def check_zero_div(self, msg):
lines = msg.splitlines()
self.assertTrue(lines[-3].startswith(' File'))
self.assertIn('1/0 # In zero_div', lines[-2])
self.assertTrue(lines[-1].startswith('ZeroDivisionError'), lines[-1])
def test_simple(self):
try:
1/0 # Marker
except ZeroDivisionError as _:
e = _
lines = self.get_report(e).splitlines()
self.assertEqual(len(lines), 4)
self.assertTrue(lines[0].startswith('Traceback'))
self.assertTrue(lines[1].startswith(' File'))
self.assertIn('1/0 # Marker', lines[2])
self.assertTrue(lines[3].startswith('ZeroDivisionError'))
def test_cause(self):
def inner_raise():
try:
self.zero_div()
except ZeroDivisionError as e:
raise KeyError from e
def outer_raise():
inner_raise() # Marker
blocks = boundaries.split(self.get_report(outer_raise))
self.assertEqual(len(blocks), 3)
self.assertEqual(blocks[1], cause_message)
self.check_zero_div(blocks[0])
self.assertIn('inner_raise() # Marker', blocks[2])
def test_context(self):
def inner_raise():
try:
self.zero_div()
except ZeroDivisionError:
raise KeyError
def outer_raise():
inner_raise() # Marker
blocks = boundaries.split(self.get_report(outer_raise))
self.assertEqual(len(blocks), 3)
self.assertEqual(blocks[1], context_message)
self.check_zero_div(blocks[0])
self.assertIn('inner_raise() # Marker', blocks[2])
def test_context_suppression(self):
try:
try:
raise Exception
except:
raise ZeroDivisionError from None
except ZeroDivisionError as _:
e = _
lines = self.get_report(e).splitlines()
self.assertEqual(len(lines), 4)
self.assertTrue(lines[0].startswith('Traceback'))
self.assertTrue(lines[1].startswith(' File'))
self.assertIn('ZeroDivisionError from None', lines[2])
self.assertTrue(lines[3].startswith('ZeroDivisionError'))
def test_cause_and_context(self):
# When both a cause and a context are set, only the cause should be
# displayed and the context should be muted.
def inner_raise():
try:
self.zero_div()
except ZeroDivisionError as _e:
e = _e
try:
xyzzy
except NameError:
raise KeyError from e
def outer_raise():
inner_raise() # Marker
blocks = boundaries.split(self.get_report(outer_raise))
self.assertEqual(len(blocks), 3)
self.assertEqual(blocks[1], cause_message)
self.check_zero_div(blocks[0])
self.assertIn('inner_raise() # Marker', blocks[2])
def test_cause_recursive(self):
def inner_raise():
try:
try:
self.zero_div()
except ZeroDivisionError as e:
z = e
raise KeyError from e
except KeyError as e:
raise z from e
def outer_raise():
inner_raise() # Marker
blocks = boundaries.split(self.get_report(outer_raise))
self.assertEqual(len(blocks), 3)
self.assertEqual(blocks[1], cause_message)
# The first block is the KeyError raised from the ZeroDivisionError
self.assertIn('raise KeyError from e', blocks[0])
self.assertNotIn('1/0', blocks[0])
# The second block (apart from the boundary) is the ZeroDivisionError
# re-raised from the KeyError
self.assertIn('inner_raise() # Marker', blocks[2])
self.check_zero_div(blocks[2])
def test_syntax_error_offset_at_eol(self):
# See #10186.
def e():
raise SyntaxError('', ('', 0, 5, 'hello'))
msg = self.get_report(e).splitlines()
self.assertEqual(msg[-2], " ^")
def e():
exec("x = 5 | 4 |")
msg = self.get_report(e).splitlines()
self.assertEqual(msg[-2], ' ^')
class PyExcReportingTests(BaseExceptionReportingTests, unittest.TestCase):
#
# This checks reporting through the 'traceback' module, with both
# format_exception() and print_exception().
#
def get_report(self, e):
e = self.get_exception(e)
s = ''.join(
traceback.format_exception(type(e), e, e.__traceback__))
with captured_output("stderr") as sio:
traceback.print_exception(type(e), e, e.__traceback__)
self.assertEqual(sio.getvalue(), s)
return s
class CExcReportingTests(BaseExceptionReportingTests, unittest.TestCase):
#
# This checks built-in reporting by the interpreter.
#
@cpython_only
def get_report(self, e):
from _testcapi import exception_print
e = self.get_exception(e)
with captured_output("stderr") as s:
exception_print(e)
return s.getvalue()
class MiscTracebackCases(unittest.TestCase):
#
# Check non-printing functions in traceback module
#
def test_clear(self):
def outer():
middle()
def middle():
inner()
def inner():
i = 1
1/0
try:
outer()
except:
type_, value, tb = sys.exc_info()
# Initial assertion: there's one local in the inner frame.
inner_frame = tb.tb_next.tb_next.tb_next.tb_frame
self.assertEqual(len(inner_frame.f_locals), 1)
# Clear traceback frames
traceback.clear_frames(tb)
# Local variable dict should now be empty.
self.assertEqual(len(inner_frame.f_locals), 0)
class TestFrame(unittest.TestCase):
def test_basics(self):
linecache.clearcache()
linecache.lazycache("f", globals())
f = traceback.FrameSummary("f", 1, "dummy")
self.assertEqual(
("f", 1, "dummy", '"""Test cases for traceback module"""'),
tuple(f))
self.assertEqual(None, f.locals)
def test_lazy_lines(self):
linecache.clearcache()
f = traceback.FrameSummary("f", 1, "dummy", lookup_line=False)
self.assertEqual(None, f._line)
linecache.lazycache("f", globals())
self.assertEqual(
'"""Test cases for traceback module"""',
f.line)
def test_explicit_line(self):
f = traceback.FrameSummary("f", 1, "dummy", line="line")
self.assertEqual("line", f.line)
class TestStack(unittest.TestCase):
def test_walk_stack(self):
s = list(traceback.walk_stack(None))
self.assertGreater(len(s), 10)
def test_walk_tb(self):
try:
1/0
except Exception:
_, _, tb = sys.exc_info()
s = list(traceback.walk_tb(tb))
self.assertEqual(len(s), 1)
def test_extract_stack(self):
s = traceback.StackSummary.extract(traceback.walk_stack(None))
self.assertIsInstance(s, traceback.StackSummary)
def test_extract_stack_limit(self):
s = traceback.StackSummary.extract(traceback.walk_stack(None), limit=5)
self.assertEqual(len(s), 5)
def test_extract_stack_lookup_lines(self):
linecache.clearcache()
linecache.updatecache('/foo.py', globals())
c = test_code('/foo.py', 'method')
f = test_frame(c, None, None)
s = traceback.StackSummary.extract(iter([(f, 6)]), lookup_lines=True)
linecache.clearcache()
self.assertEqual(s[0].line, "import sys")
def test_extract_stackup_deferred_lookup_lines(self):
linecache.clearcache()
c = test_code('/foo.py', 'method')
f = test_frame(c, None, None)
s = traceback.StackSummary.extract(iter([(f, 6)]), lookup_lines=False)
self.assertEqual({}, linecache.cache)
linecache.updatecache('/foo.py', globals())
self.assertEqual(s[0].line, "import sys")
def test_from_list(self):
s = traceback.StackSummary.from_list([('foo.py', 1, 'fred', 'line')])
self.assertEqual(
[' File "foo.py", line 1, in fred\n line\n'],
s.format())
def test_from_list_edited_stack(self):
s = traceback.StackSummary.from_list([('foo.py', 1, 'fred', 'line')])
s[0] = ('foo.py', 2, 'fred', 'line')
s2 = traceback.StackSummary.from_list(s)
self.assertEqual(
[' File "foo.py", line 2, in fred\n line\n'],
s2.format())
def test_format_smoke(self):
# For detailed tests see the format_list tests, which consume the same
# code.
s = traceback.StackSummary.from_list([('foo.py', 1, 'fred', 'line')])
self.assertEqual(
[' File "foo.py", line 1, in fred\n line\n'],
s.format())
def test_locals(self):
linecache.updatecache('/foo.py', globals())
c = test_code('/foo.py', 'method')
f = test_frame(c, globals(), {'something': 1})
s = traceback.StackSummary.extract(iter([(f, 6)]), capture_locals=True)
self.assertEqual(s[0].locals, {'something': '1'})
def test_no_locals(self):
linecache.updatecache('/foo.py', globals())
c = test_code('/foo.py', 'method')
f = test_frame(c, globals(), {'something': 1})
s = traceback.StackSummary.extract(iter([(f, 6)]))
self.assertEqual(s[0].locals, None)
def test_format_locals(self):
def some_inner(k, v):
a = 1
b = 2
return traceback.StackSummary.extract(
traceback.walk_stack(None), capture_locals=True, limit=1)
s = some_inner(3, 4)
self.assertEqual(
[' File "' + __file__ + '", line 593, '
'in some_inner\n'
' traceback.walk_stack(None), capture_locals=True, limit=1)\n'
' a = 1\n'
' b = 2\n'
' k = 3\n'
' v = 4\n'
], s.format())
class TestTracebackException(unittest.TestCase):
def test_smoke(self):
try:
1/0
except Exception:
exc_info = sys.exc_info()
exc = traceback.TracebackException(*exc_info)
expected_stack = traceback.StackSummary.extract(
traceback.walk_tb(exc_info[2]))
self.assertEqual(None, exc.__cause__)
self.assertEqual(None, exc.__context__)
self.assertEqual(False, exc.__suppress_context__)
self.assertEqual(expected_stack, exc.stack)
self.assertEqual(exc_info[0], exc.exc_type)
self.assertEqual(str(exc_info[1]), str(exc))
def test_from_exception(self):
# Check all the parameters are accepted.
def foo():
1/0
try:
foo()
except Exception as e:
exc_info = sys.exc_info()
self.expected_stack = traceback.StackSummary.extract(
traceback.walk_tb(exc_info[2]), limit=1, lookup_lines=False,
capture_locals=True)
self.exc = traceback.TracebackException.from_exception(
e, limit=1, lookup_lines=False, capture_locals=True)
expected_stack = self.expected_stack
exc = self.exc
self.assertEqual(None, exc.__cause__)
self.assertEqual(None, exc.__context__)
self.assertEqual(False, exc.__suppress_context__)
self.assertEqual(expected_stack, exc.stack)
self.assertEqual(exc_info[0], exc.exc_type)
self.assertEqual(str(exc_info[1]), str(exc))
def test_cause(self):
try:
try:
1/0
finally:
exc_info_context = sys.exc_info()
exc_context = traceback.TracebackException(*exc_info_context)
cause = Exception("cause")
raise Exception("uh oh") from cause
except Exception:
exc_info = sys.exc_info()
exc = traceback.TracebackException(*exc_info)
expected_stack = traceback.StackSummary.extract(
traceback.walk_tb(exc_info[2]))
exc_cause = traceback.TracebackException(Exception, cause, None)
self.assertEqual(exc_cause, exc.__cause__)
self.assertEqual(exc_context, exc.__context__)
self.assertEqual(True, exc.__suppress_context__)
self.assertEqual(expected_stack, exc.stack)
self.assertEqual(exc_info[0], exc.exc_type)
self.assertEqual(str(exc_info[1]), str(exc))
def test_context(self):
try:
try:
1/0
finally:
exc_info_context = sys.exc_info()
exc_context = traceback.TracebackException(*exc_info_context)
raise Exception("uh oh")
except Exception:
exc_info = sys.exc_info()
exc = traceback.TracebackException(*exc_info)
expected_stack = traceback.StackSummary.extract(
traceback.walk_tb(exc_info[2]))
self.assertEqual(None, exc.__cause__)
self.assertEqual(exc_context, exc.__context__)
self.assertEqual(False, exc.__suppress_context__)
self.assertEqual(expected_stack, exc.stack)
self.assertEqual(exc_info[0], exc.exc_type)
self.assertEqual(str(exc_info[1]), str(exc))
def test_limit(self):
def recurse(n):
if n:
recurse(n-1)
else:
1/0
try:
recurse(10)
except Exception:
exc_info = sys.exc_info()
exc = traceback.TracebackException(*exc_info, limit=5)
expected_stack = traceback.StackSummary.extract(
traceback.walk_tb(exc_info[2]), limit=5)
self.assertEqual(expected_stack, exc.stack)
def test_lookup_lines(self):
linecache.clearcache()
e = Exception("uh oh")
c = test_code('/foo.py', 'method')
f = test_frame(c, None, None)
tb = test_tb(f, 6, None)
exc = traceback.TracebackException(Exception, e, tb, lookup_lines=False)
self.assertEqual({}, linecache.cache)
linecache.updatecache('/foo.py', globals())
self.assertEqual(exc.stack[0].line, "import sys")
def test_locals(self):
linecache.updatecache('/foo.py', globals())
e = Exception("uh oh")
c = test_code('/foo.py', 'method')
f = test_frame(c, globals(), {'something': 1, 'other': 'string'})
tb = test_tb(f, 6, None)
exc = traceback.TracebackException(
Exception, e, tb, capture_locals=True)
self.assertEqual(
exc.stack[0].locals, {'something': '1', 'other': "'string'"})
def test_no_locals(self):
linecache.updatecache('/foo.py', globals())
e = Exception("uh oh")
c = test_code('/foo.py', 'method')
f = test_frame(c, globals(), {'something': 1})
tb = test_tb(f, 6, None)
exc = traceback.TracebackException(Exception, e, tb)
self.assertEqual(exc.stack[0].locals, None)
def test_main():
run_unittest(__name__)
if __name__ == "__main__":
test_main()