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Code Issues Releases Activity

refactor traceback.py to reduce code duplication (closes #17646)

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Patch by Martin Morrison.
This commit is contained in:
Benjamin Peterson 2013-04-29 16:09:39 -04:00
parent 0bb83f812f
commit d9fec15e9b
2 changed files with 133 additions and 144 deletions
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28
Lib/test/test_traceback.py
View File

@ -160,11 +160,26 @@ class TracebackFormatTests(unittest.TestCase):
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()
@ -174,6 +189,19 @@ class TracebackFormatTests(unittest.TestCase):
self.assertTrue(location.startswith(' File'))
self.assertTrue(source_line.startswith(' raise'))
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 "

249
Lib/traceback.py
View File

@ -2,26 +2,31 @@
import linecache
import sys
import operator
__all__ = ['extract_stack', 'extract_tb', 'format_exception',
'format_exception_only', 'format_list', 'format_stack',
'format_tb', 'print_exc', 'format_exc', 'print_exception',
'print_last', 'print_stack', 'print_tb']
def _print(file, str='', terminator='\n'):
file.write(str+terminator)
#
# Formatting and printing lists of traceback lines.
#
def _format_list_iter(extracted_list):
for filename, lineno, name, line in extracted_list:
item = ' File "{}", line {}, in {}\n'.format(filename, lineno, name)
if line:
item = item + ' {}\n'.format(line.strip())
yield item
def print_list(extracted_list, file=None):
"""Print the list of tuples as returned by extract_tb() or
extract_stack() as a formatted stack trace to the given file."""
if file is None:
file = sys.stderr
for filename, lineno, name, line in extracted_list:
_print(file,
' File "%s", line %d, in %s' % (filename,lineno,name))
if line:
_print(file, ' %s' % line.strip())
for item in _format_list_iter(extracted_list):
print(item, file=file, end="")
def format_list(extracted_list):
"""Format a list of traceback entry tuples for printing.
@ -33,14 +38,44 @@ def format_list(extracted_list):
the strings may contain internal newlines as well, for those items
whose source text line is not None.
"""
list = []
for filename, lineno, name, line in extracted_list:
item = ' File "%s", line %d, in %s\n' % (filename,lineno,name)
if line:
item = item + ' %s\n' % line.strip()
list.append(item)
return list
return list(_format_list_iter(extracted_list))
#
# Printing and Extracting Tracebacks.
#
# extractor takes curr and needs to return a tuple of:
# - Frame object
# - Line number
# - Next item (same type as curr)
# In practice, curr is either a traceback or a frame.
def _extract_tb_or_stack_iter(curr, limit, extractor):
if limit is None:
limit = getattr(sys, 'tracebacklimit', None)
n = 0
while curr is not None and (limit is None or n < limit):
f, lineno, next_item = extractor(curr)
co = f.f_code
filename = co.co_filename
name = co.co_name
linecache.checkcache(filename)
line = linecache.getline(filename, lineno, f.f_globals)
if line:
line = line.strip()
else:
line = None
yield (filename, lineno, name, line)
curr = next_item
n += 1
def _extract_tb_iter(tb, limit):
return _extract_tb_or_stack_iter(
tb, limit,
operator.attrgetter("tb_frame", "tb_lineno", "tb_next"))
def print_tb(tb, limit=None, file=None):
"""Print up to 'limit' stack trace entries from the traceback 'tb'.
@ -50,29 +85,11 @@ def print_tb(tb, limit=None, file=None):
'file' should be an open file or file-like object with a write()
method.
"""
if file is None:
file = sys.stderr
if limit is None:
if hasattr(sys, 'tracebacklimit'):
limit = sys.tracebacklimit
n = 0
while tb is not None and (limit is None or n < limit):
f = tb.tb_frame
lineno = tb.tb_lineno
co = f.f_code
filename = co.co_filename
name = co.co_name
_print(file,
' File "%s", line %d, in %s' % (filename, lineno, name))
linecache.checkcache(filename)
line = linecache.getline(filename, lineno, f.f_globals)
if line: _print(file, ' ' + line.strip())
tb = tb.tb_next
n = n+1
print_list(extract_tb(tb, limit=limit), file=file)
def format_tb(tb, limit=None):
"""A shorthand for 'format_list(extract_stack(f, limit))."""
return format_list(extract_tb(tb, limit))
"""A shorthand for 'format_list(extract_tb(tb, limit))."""
return format_list(extract_tb(tb, limit=limit))
def extract_tb(tb, limit=None):
"""Return list of up to limit pre-processed entries from traceback.
@ -85,26 +102,11 @@ def extract_tb(tb, limit=None):
leading and trailing whitespace stripped; if the source is not
available it is None.
"""
if limit is None:
if hasattr(sys, 'tracebacklimit'):
limit = sys.tracebacklimit
list = []
n = 0
while tb is not None and (limit is None or n < limit):
f = tb.tb_frame
lineno = tb.tb_lineno
co = f.f_code
filename = co.co_filename
name = co.co_name
linecache.checkcache(filename)
line = linecache.getline(filename, lineno, f.f_globals)
if line: line = line.strip()
else: line = None
list.append((filename, lineno, name, line))
tb = tb.tb_next
n = n+1
return list
return list(_extract_tb_iter(tb, limit=limit))
#
# Exception formatting and output.
#
_cause_message = (
"\nThe above exception was the direct cause "
@ -134,6 +136,21 @@ def _iter_chain(exc, custom_tb=None, seen=None):
for it in its:
yield from it
def _format_exception_iter(etype, value, tb, limit, chain):
if chain:
values = _iter_chain(value, tb)
else:
values = [(value, tb)]
for value, tb in values:
if isinstance(value, str):
# This is a cause/context message line
yield value + '\n'
continue
if tb:
yield 'Traceback (most recent call last):\n'
yield from _format_list_iter(_extract_tb_iter(tb, limit=limit))
yield from _format_exception_only_iter(type(value), value)
def print_exception(etype, value, tb, limit=None, file=None, chain=True):
"""Print exception up to 'limit' stack trace entries from 'tb' to 'file'.
@ -148,20 +165,8 @@ def print_exception(etype, value, tb, limit=None, file=None, chain=True):
"""
if file is None:
file = sys.stderr
if chain:
values = _iter_chain(value, tb)
else:
values = [(value, tb)]
for value, tb in values:
if isinstance(value, str):
_print(file, value)
continue
if tb:
_print(file, 'Traceback (most recent call last):')
print_tb(tb, limit, file)
lines = format_exception_only(type(value), value)
for line in lines:
_print(file, line, '')
for line in _format_exception_iter(etype, value, tb, limit, chain):
print(line, file=file, end="")
def format_exception(etype, value, tb, limit=None, chain=True):
"""Format a stack trace and the exception information.
@ -172,20 +177,7 @@ def format_exception(etype, value, tb, limit=None, chain=True):
these lines are concatenated and printed, exactly the same text is
printed as does print_exception().
"""
list = []
if chain:
values = _iter_chain(value, tb)
else:
values = [(value, tb)]
for value, tb in values:
if isinstance(value, str):
list.append(value + '\n')
continue
if tb:
list.append('Traceback (most recent call last):\n')
list.extend(format_tb(tb, limit))
list.extend(format_exception_only(type(value), value))
return list
return list(_format_exception_iter(etype, value, tb, limit, chain))
def format_exception_only(etype, value):
"""Format the exception part of a traceback.
@ -203,10 +195,14 @@ def format_exception_only(etype, value):
string in the list.
"""
return list(_format_exception_only_iter(etype, value))
def _format_exception_only_iter(etype, value):
# Gracefully handle (the way Python 2.4 and earlier did) the case of
# being called with (None, None).
if etype is None:
return [_format_final_exc_line(etype, value)]
yield _format_final_exc_line(etype, value)
return
stype = etype.__name__
smod = etype.__module__
@ -214,26 +210,26 @@ def format_exception_only(etype, value):
stype = smod + '.' + stype
if not issubclass(etype, SyntaxError):
return [_format_final_exc_line(stype, value)]
yield _format_final_exc_line(stype, value)
return
# It was a syntax error; show exactly where the problem was found.
lines = []
filename = value.filename or "<string>"
lineno = str(value.lineno) or '?'
lines.append(' File "%s", line %s\n' % (filename, lineno))
yield ' File "{}", line {}\n'.format(filename, lineno)
badline = value.text
offset = value.offset
if badline is not None:
lines.append(' %s\n' % badline.strip())
yield ' {}\n'.format(badline.strip())
if offset is not None:
caretspace = badline.rstrip('\n')[:offset].lstrip()
# non-space whitespace (likes tabs) must be kept for alignment
caretspace = ((c.isspace() and c or ' ') for c in caretspace)
# only three spaces to account for offset1 == pos 0
lines.append(' %s^\n' % ''.join(caretspace))
yield ' {}^\n'.format(''.join(caretspace))
msg = value.msg or "<no detail available>"
lines.append("%s: %s\n" % (stype, msg))
return lines
yield "{}: {}\n".format(stype, msg)
def _format_final_exc_line(etype, value):
valuestr = _some_str(value)
@ -249,38 +245,34 @@ def _some_str(value):
except:
return '<unprintable %s object>' % type(value).__name__
def print_exc(limit=None, file=None, chain=True):
"""Shorthand for 'print_exception(*sys.exc_info(), limit, file)'."""
if file is None:
file = sys.stderr
try:
etype, value, tb = sys.exc_info()
print_exception(etype, value, tb, limit, file, chain)
finally:
etype = value = tb = None
print_exception(*sys.exc_info(), limit=limit, file=file, chain=chain)
def format_exc(limit=None, chain=True):
"""Like print_exc() but return a string."""
try:
etype, value, tb = sys.exc_info()
return ''.join(
format_exception(etype, value, tb, limit, chain))
finally:
etype = value = tb = None
return "".join(format_exception(*sys.exc_info(), limit=limit, chain=chain))
def print_last(limit=None, file=None, chain=True):
"""This is a shorthand for 'print_exception(sys.last_type,
sys.last_value, sys.last_traceback, limit, file)'."""
if not hasattr(sys, "last_type"):
raise ValueError("no last exception")
if file is None:
file = sys.stderr
print_exception(sys.last_type, sys.last_value, sys.last_traceback,
limit, file, chain)
#
# Printing and Extracting Stacks.
#
def _extract_stack_iter(f, limit=None):
return _extract_tb_or_stack_iter(
f, limit, lambda f: (f, f.f_lineno, f.f_back))
def _get_stack(f):
if f is None:
f = sys._getframe().f_back.f_back
return f
def print_stack(f=None, limit=None, file=None):
"""Print a stack trace from its invocation point.
@ -289,21 +281,11 @@ def print_stack(f=None, limit=None, file=None):
stack frame at which to start. The optional 'limit' and 'file'
arguments have the same meaning as for print_exception().
"""
if f is None:
try:
raise ZeroDivisionError
except ZeroDivisionError:
f = sys.exc_info()[2].tb_frame.f_back
print_list(extract_stack(f, limit), file)
print_list(extract_stack(_get_stack(f), limit=limit), file=file)
def format_stack(f=None, limit=None):
"""Shorthand for 'format_list(extract_stack(f, limit))'."""
if f is None:
try:
raise ZeroDivisionError
except ZeroDivisionError:
f = sys.exc_info()[2].tb_frame.f_back
return format_list(extract_stack(f, limit))
return format_list(extract_stack(_get_stack(f), limit=limit))
def extract_stack(f=None, limit=None):
"""Extract the raw traceback from the current stack frame.
@ -314,27 +296,6 @@ def extract_stack(f=None, limit=None):
line number, function name, text), and the entries are in order
from oldest to newest stack frame.
"""
if f is None:
try:
raise ZeroDivisionError
except ZeroDivisionError:
f = sys.exc_info()[2].tb_frame.f_back
if limit is None:
if hasattr(sys, 'tracebacklimit'):
limit = sys.tracebacklimit
list = []
n = 0
while f is not None and (limit is None or n < limit):
lineno = f.f_lineno
co = f.f_code
filename = co.co_filename
name = co.co_name
linecache.checkcache(filename)
line = linecache.getline(filename, lineno, f.f_globals)
if line: line = line.strip()
else: line = None
list.append((filename, lineno, name, line))
f = f.f_back
n = n+1
list.reverse()
return list
stack = list(_extract_stack_iter(_get_stack(f), limit=limit))
stack.reverse()
return stack