import re
import sys
from test import support
from .util import (
BREAKPOINT_FN, GDB_VERSION,
run_gdb, setup_module, DebuggerTests)
def setUpModule():
setup_module()
class PrettyPrintTests(DebuggerTests):
def get_gdb_repr(self, source,
cmds_after_breakpoint=None,
import_site=False):
# Given an input python source representation of data,
# run "python -c'id(DATA)'" under gdb with a breakpoint on
# builtin_id and scrape out gdb's representation of the "op"
# parameter, and verify that the gdb displays the same string
#
# Verify that the gdb displays the expected string
#
# For a nested structure, the first time we hit the breakpoint will
# give us the top-level structure
# NOTE: avoid decoding too much of the traceback as some
# undecodable characters may lurk there in optimized mode
# (issue #19743).
cmds_after_breakpoint = cmds_after_breakpoint or ["backtrace 1"]
gdb_output = self.get_stack_trace(source, breakpoint=BREAKPOINT_FN,
cmds_after_breakpoint=cmds_after_breakpoint,
import_site=import_site)
# gdb can insert additional '\n' and space characters in various places
# in its output, depending on the width of the terminal it's connected
# to (using its "wrap_here" function)
m = re.search(
# Match '#0 builtin_id(self=..., v=...)'
r'#0\s+builtin_id\s+\(self\=.*,\s+v=\s*(.*?)?\)'
# Match ' at Python/bltinmodule.c'.
# bpo-38239: builtin_id() is defined in Python/bltinmodule.c,
# but accept any "Directory\file.c" to support Link Time
# Optimization (LTO).
r'\s+at\s+\S*[A-Za-z]+/[A-Za-z0-9_-]+\.c',
gdb_output, re.DOTALL)
if not m:
self.fail('Unexpected gdb output: %r\n%s' % (gdb_output, gdb_output))
return m.group(1), gdb_output
def test_getting_backtrace(self):
gdb_output = self.get_stack_trace('id(42)')
self.assertTrue(BREAKPOINT_FN in gdb_output)
def assertGdbRepr(self, val, exp_repr=None):
# Ensure that gdb's rendering of the value in a debugged process
# matches repr(value) in this process:
gdb_repr, gdb_output = self.get_gdb_repr('id(' + ascii(val) + ')')
if not exp_repr:
exp_repr = repr(val)
self.assertEqual(gdb_repr, exp_repr,
('%r did not equal expected %r; full output was:\n%s'
% (gdb_repr, exp_repr, gdb_output)))
@support.requires_resource('cpu')
def test_int(self):
'Verify the pretty-printing of various int values'
self.assertGdbRepr(42)
self.assertGdbRepr(0)
self.assertGdbRepr(-7)
self.assertGdbRepr(1000000000000)
self.assertGdbRepr(-1000000000000000)
def test_singletons(self):
'Verify the pretty-printing of True, False and None'
self.assertGdbRepr(True)
self.assertGdbRepr(False)
self.assertGdbRepr(None)
def test_dicts(self):
'Verify the pretty-printing of dictionaries'
self.assertGdbRepr({})
self.assertGdbRepr({'foo': 'bar'}, "{'foo': 'bar'}")
# Python preserves insertion order since 3.6
self.assertGdbRepr({'foo': 'bar', 'douglas': 42}, "{'foo': 'bar', 'douglas': 42}")
def test_lists(self):
'Verify the pretty-printing of lists'
self.assertGdbRepr([])
self.assertGdbRepr(list(range(5)))
@support.requires_resource('cpu')
def test_bytes(self):
'Verify the pretty-printing of bytes'
self.assertGdbRepr(b'')
self.assertGdbRepr(b'And now for something hopefully the same')
self.assertGdbRepr(b'string with embedded NUL here \0 and then some more text')
self.assertGdbRepr(b'this is a tab:\t'
b' this is a slash-N:\n'
b' this is a slash-R:\r'
)
self.assertGdbRepr(b'this is byte 255:\xff and byte 128:\x80')
self.assertGdbRepr(bytes([b for b in range(255)]))
@support.requires_resource('cpu')
def test_strings(self):
'Verify the pretty-printing of unicode strings'
# We cannot simply call locale.getpreferredencoding() here,
# as GDB might have been linked against a different version
# of Python with a different encoding and coercion policy
# with respect to PEP 538 and PEP 540.
stdout, stderr = run_gdb(
'--eval-command',
'python import locale; print(locale.getpreferredencoding())')
encoding = stdout
if stderr or not encoding:
raise RuntimeError(
f'unable to determine the Python locale preferred encoding '
f'of embedded Python in GDB\n'
f'stdout={stdout!r}\n'
f'stderr={stderr!r}')
def check_repr(text):
try:
text.encode(encoding)
except UnicodeEncodeError:
self.assertGdbRepr(text, ascii(text))
else:
self.assertGdbRepr(text)
self.assertGdbRepr('')
self.assertGdbRepr('And now for something hopefully the same')
self.assertGdbRepr('string with embedded NUL here \0 and then some more text')
# Test printing a single character:
# U+2620 SKULL AND CROSSBONES
check_repr('\u2620')
# Test printing a Japanese unicode string
# (I believe this reads "mojibake", using 3 characters from the CJK
# Unified Ideographs area, followed by U+3051 HIRAGANA LETTER KE)
check_repr('\u6587\u5b57\u5316\u3051')
# Test a character outside the BMP:
# U+1D121 MUSICAL SYMBOL C CLEF
# This is:
# UTF-8: 0xF0 0x9D 0x84 0xA1
# UTF-16: 0xD834 0xDD21
check_repr(chr(0x1D121))
def test_tuples(self):
'Verify the pretty-printing of tuples'
self.assertGdbRepr(tuple(), '()')
self.assertGdbRepr((1,), '(1,)')
self.assertGdbRepr(('foo', 'bar', 'baz'))
@support.requires_resource('cpu')
def test_sets(self):
'Verify the pretty-printing of sets'
if GDB_VERSION < (7, 3):
self.skipTest("pretty-printing of sets needs gdb 7.3 or later")
self.assertGdbRepr(set(), "set()")
self.assertGdbRepr(set(['a']), "{'a'}")
# PYTHONHASHSEED is need to get the exact frozenset item order
if not sys.flags.ignore_environment:
self.assertGdbRepr(set(['a', 'b']), "{'a', 'b'}")
self.assertGdbRepr(set([4, 5, 6]), "{4, 5, 6}")
# Ensure that we handle sets containing the "dummy" key value,
# which happens on deletion:
gdb_repr, gdb_output = self.get_gdb_repr('''s = set(['a','b'])
s.remove('a')
id(s)''')
self.assertEqual(gdb_repr, "{'b'}")
@support.requires_resource('cpu')
def test_frozensets(self):
'Verify the pretty-printing of frozensets'
if GDB_VERSION < (7, 3):
self.skipTest("pretty-printing of frozensets needs gdb 7.3 or later")
self.assertGdbRepr(frozenset(), "frozenset()")
self.assertGdbRepr(frozenset(['a']), "frozenset({'a'})")
# PYTHONHASHSEED is need to get the exact frozenset item order
if not sys.flags.ignore_environment:
self.assertGdbRepr(frozenset(['a', 'b']), "frozenset({'a', 'b'})")
self.assertGdbRepr(frozenset([4, 5, 6]), "frozenset({4, 5, 6})")
def test_exceptions(self):
# Test a RuntimeError
gdb_repr, gdb_output = self.get_gdb_repr('''
try:
raise RuntimeError("I am an error")
except RuntimeError as e:
id(e)
''')
self.assertEqual(gdb_repr,
"RuntimeError('I am an error',)")
# Test division by zero:
gdb_repr, gdb_output = self.get_gdb_repr('''
try:
a = 1 / 0
except ZeroDivisionError as e:
id(e)
''')
self.assertEqual(gdb_repr,
"ZeroDivisionError('division by zero',)")
def test_modern_class(self):
'Verify the pretty-printing of new-style class instances'
gdb_repr, gdb_output = self.get_gdb_repr('''
class Foo:
pass
foo = Foo()
foo.an_int = 42
id(foo)''')
m = re.match(r'<Foo\(an_int=42\) at remote 0x-?[0-9a-f]+>', gdb_repr)
self.assertTrue(m,
msg='Unexpected new-style class rendering %r' % gdb_repr)
def test_subclassing_list(self):
'Verify the pretty-printing of an instance of a list subclass'
gdb_repr, gdb_output = self.get_gdb_repr('''
class Foo(list):
pass
foo = Foo()
foo += [1, 2, 3]
foo.an_int = 42
id(foo)''')
m = re.match(r'<Foo\(an_int=42\) at remote 0x-?[0-9a-f]+>', gdb_repr)
self.assertTrue(m,
msg='Unexpected new-style class rendering %r' % gdb_repr)
def test_subclassing_tuple(self):
'Verify the pretty-printing of an instance of a tuple subclass'
# This should exercise the negative tp_dictoffset code in the
# new-style class support
gdb_repr, gdb_output = self.get_gdb_repr('''
class Foo(tuple):
pass
foo = Foo((1, 2, 3))
foo.an_int = 42
id(foo)''')
m = re.match(r'<Foo\(an_int=42\) at remote 0x-?[0-9a-f]+>', gdb_repr)
self.assertTrue(m,
msg='Unexpected new-style class rendering %r' % gdb_repr)
def assertSane(self, source, corruption, exprepr=None):
'''Run Python under gdb, corrupting variables in the inferior process
immediately before taking a backtrace.
Verify that the variable's representation is the expected failsafe
representation'''
if corruption:
cmds_after_breakpoint=[corruption, 'backtrace']
else:
cmds_after_breakpoint=['backtrace']
gdb_repr, gdb_output = \
self.get_gdb_repr(source,
cmds_after_breakpoint=cmds_after_breakpoint)
if exprepr:
if gdb_repr == exprepr:
# gdb managed to print the value in spite of the corruption;
# this is good (see http://bugs.python.org/issue8330)
return
# Match anything for the type name; 0xDEADBEEF could point to
# something arbitrary (see http://bugs.python.org/issue8330)
pattern = '<.* at remote 0x-?[0-9a-f]+>'
m = re.match(pattern, gdb_repr)
if not m:
self.fail('Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
def test_NULL_ptr(self):
'Ensure that a NULL PyObject* is handled gracefully'
gdb_repr, gdb_output = (
self.get_gdb_repr('id(42)',
cmds_after_breakpoint=['set variable v=0',
'backtrace'])
)
self.assertEqual(gdb_repr, '0x0')
def test_NULL_ob_type(self):
'Ensure that a PyObject* with NULL ob_type is handled gracefully'
self.assertSane('id(42)',
'set v->ob_type=0')
def test_corrupt_ob_type(self):
'Ensure that a PyObject* with a corrupt ob_type is handled gracefully'
self.assertSane('id(42)',
'set v->ob_type=0xDEADBEEF',
exprepr='42')
def test_corrupt_tp_flags(self):
'Ensure that a PyObject* with a type with corrupt tp_flags is handled'
self.assertSane('id(42)',
'set v->ob_type->tp_flags=0x0',
exprepr='42')
def test_corrupt_tp_name(self):
'Ensure that a PyObject* with a type with corrupt tp_name is handled'
self.assertSane('id(42)',
'set v->ob_type->tp_name=0xDEADBEEF',
exprepr='42')
def test_builtins_help(self):
'Ensure that the new-style class _Helper in site.py can be handled'
if sys.flags.no_site:
self.skipTest("need site module, but -S option was used")
# (this was the issue causing tracebacks in
# http://bugs.python.org/issue8032#msg100537 )
gdb_repr, gdb_output = self.get_gdb_repr('id(__builtins__.help)', import_site=True)
m = re.match(r'<_Helper\(\) at remote 0x-?[0-9a-f]+>', gdb_repr)
self.assertTrue(m,
msg='Unexpected rendering %r' % gdb_repr)
def test_selfreferential_list(self):
'''Ensure that a reference loop involving a list doesn't lead proxyval
into an infinite loop:'''
gdb_repr, gdb_output = \
self.get_gdb_repr("a = [3, 4, 5] ; a.append(a) ; id(a)")
self.assertEqual(gdb_repr, '[3, 4, 5, [...]]')
gdb_repr, gdb_output = \
self.get_gdb_repr("a = [3, 4, 5] ; b = [a] ; a.append(b) ; id(a)")
self.assertEqual(gdb_repr, '[3, 4, 5, [[...]]]')
def test_selfreferential_dict(self):
'''Ensure that a reference loop involving a dict doesn't lead proxyval
into an infinite loop:'''
gdb_repr, gdb_output = \
self.get_gdb_repr("a = {} ; b = {'bar':a} ; a['foo'] = b ; id(a)")
self.assertEqual(gdb_repr, "{'foo': {'bar': {...}}}")
def test_selfreferential_old_style_instance(self):
gdb_repr, gdb_output = \
self.get_gdb_repr('''
class Foo:
pass
foo = Foo()
foo.an_attr = foo
id(foo)''')
self.assertTrue(re.match(r'<Foo\(an_attr=<\.\.\.>\) at remote 0x-?[0-9a-f]+>',
gdb_repr),
'Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
def test_selfreferential_new_style_instance(self):
gdb_repr, gdb_output = \
self.get_gdb_repr('''
class Foo(object):
pass
foo = Foo()
foo.an_attr = foo
id(foo)''')
self.assertTrue(re.match(r'<Foo\(an_attr=<\.\.\.>\) at remote 0x-?[0-9a-f]+>',
gdb_repr),
'Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
gdb_repr, gdb_output = \
self.get_gdb_repr('''
class Foo(object):
pass
a = Foo()
b = Foo()
a.an_attr = b
b.an_attr = a
id(a)''')
self.assertTrue(re.match(r'<Foo\(an_attr=<Foo\(an_attr=<\.\.\.>\) at remote 0x-?[0-9a-f]+>\) at remote 0x-?[0-9a-f]+>',
gdb_repr),
'Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
def test_truncation(self):
'Verify that very long output is truncated'
gdb_repr, gdb_output = self.get_gdb_repr('id(list(range(1000)))')
self.assertEqual(gdb_repr,
"[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, "
"14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, "
"27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, "
"40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, "
"53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, "
"66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, "
"79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, "
"92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, "
"104, 105, 106, 107, 108, 109, 110, 111, 112, 113, "
"114, 115, 116, 117, 118, 119, 120, 121, 122, 123, "
"124, 125, 126, 127, 128, 129, 130, 131, 132, 133, "
"134, 135, 136, 137, 138, 139, 140, 141, 142, 143, "
"144, 145, 146, 147, 148, 149, 150, 151, 152, 153, "
"154, 155, 156, 157, 158, 159, 160, 161, 162, 163, "
"164, 165, 166, 167, 168, 169, 170, 171, 172, 173, "
"174, 175, 176, 177, 178, 179, 180, 181, 182, 183, "
"184, 185, 186, 187, 188, 189, 190, 191, 192, 193, "
"194, 195, 196, 197, 198, 199, 200, 201, 202, 203, "
"204, 205, 206, 207, 208, 209, 210, 211, 212, 213, "
"214, 215, 216, 217, 218, 219, 220, 221, 222, 223, "
"224, 225, 226...(truncated)")
self.assertEqual(len(gdb_repr),
1024 + len('...(truncated)'))
def test_builtin_method(self):
gdb_repr, gdb_output = self.get_gdb_repr('import sys; id(sys.stdout.readlines)')
self.assertTrue(re.match(r'<built-in method readlines of _io.TextIOWrapper object at remote 0x-?[0-9a-f]+>',
gdb_repr),
'Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
def test_frames(self):
gdb_output = self.get_stack_trace('''
import sys
def foo(a, b, c):
return sys._getframe(0)
f = foo(3, 4, 5)
id(f)''',
breakpoint='builtin_id',
cmds_after_breakpoint=['print (PyFrameObject*)v']
)
self.assertTrue(re.match(r'.*\s+\$1 =\s+Frame 0x-?[0-9a-f]+, for file <string>, line 4, in foo \(a=3.*',
gdb_output,
re.DOTALL),
'Unexpected gdb representation: %r\n%s' % (gdb_output, gdb_output))
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