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# -*- coding: utf-8 -*-
"""
ultratb.py -- Spice up your tracebacks!
* ColorTB
I've always found it a bit hard to visually parse tracebacks in Python. The
ColorTB class is a solution to that problem. It colors the different parts of a
traceback in a manner similar to what you would expect from a syntax-highlighting
text editor.
Installation instructions for ColorTB:
import sys,ultratb
sys.excepthook = ultratb.ColorTB()
* VerboseTB
I've also included a port of Ka-Ping Yee's "cgitb.py" that produces all kinds
of useful info when a traceback occurs. Ping originally had it spit out HTML
and intended it for CGI programmers, but why should they have all the fun? I
altered it to spit out colored text to the terminal. It's a bit overwhelming,
but kind of neat, and maybe useful for long-running programs that you believe
are bug-free. If a crash *does* occur in that type of program you want details.
Give it a shot--you'll love it or you'll hate it.
Note:
The Verbose mode prints the variables currently visible where the exception
happened (shortening their strings if too long). This can potentially be
very slow, if you happen to have a huge data structure whose string
representation is complex to compute. Your computer may appear to freeze for
a while with cpu usage at 100%. If this occurs, you can cancel the traceback
with Ctrl-C (maybe hitting it more than once).
If you encounter this kind of situation often, you may want to use the
Verbose_novars mode instead of the regular Verbose, which avoids formatting
variables (but otherwise includes the information and context given by
Verbose).
Installation instructions for ColorTB:
import sys,ultratb
sys.excepthook = ultratb.VerboseTB()
Note: Much of the code in this module was lifted verbatim from the standard
library module 'traceback.py' and Ka-Ping Yee's 'cgitb.py'.
* Color schemes
The colors are defined in the class TBTools through the use of the
ColorSchemeTable class. Currently the following exist:
- NoColor: allows all of this module to be used in any terminal (the color
escapes are just dummy blank strings).
- Linux: is meant to look good in a terminal like the Linux console (black
or very dark background).
- LightBG: similar to Linux but swaps dark/light colors to be more readable
in light background terminals.
You can implement other color schemes easily, the syntax is fairly
self-explanatory. Please send back new schemes you develop to the author for
possible inclusion in future releases.
"""
#*****************************************************************************
# Copyright (C) 2001 Nathaniel Gray <n8gray@caltech.edu>
# Copyright (C) 2001-2004 Fernando Perez <fperez@colorado.edu>
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#*****************************************************************************
from __future__ import with_statement
import inspect
import keyword
import linecache
import os
import pydoc
import re
import sys
import time
import tokenize
import traceback
import types
# For purposes of monkeypatching inspect to fix a bug in it.
from inspect import getsourcefile, getfile, getmodule,\
ismodule, isclass, ismethod, isfunction, istraceback, isframe, iscode
# IPython's own modules
# Modified pdb which doesn't damage IPython's readline handling
from IPython.core import debugger, ipapi
from IPython.core.display_trap import DisplayTrap
from IPython.core.excolors import exception_colors
from IPython.utils import PyColorize
from IPython.utils import io
from IPython.utils.data import uniq_stable
from IPython.utils.warn import info, error
# Globals
# amount of space to put line numbers before verbose tracebacks
INDENT_SIZE = 8
# Default color scheme. This is used, for example, by the traceback
# formatter. When running in an actual IPython instance, the user's rc.colors
# value is used, but havinga module global makes this functionality available
# to users of ultratb who are NOT running inside ipython.
DEFAULT_SCHEME = 'NoColor'
#---------------------------------------------------------------------------
# Code begins
# Utility functions
def inspect_error():
"""Print a message about internal inspect errors.
These are unfortunately quite common."""
error('Internal Python error in the inspect module.\n'
'Below is the traceback from this internal error.\n')
def findsource(object):
"""Return the entire source file and starting line number for an object.
The argument may be a module, class, method, function, traceback, frame,
or code object. The source code is returned as a list of all the lines
in the file and the line number indexes a line in that list. An IOError
is raised if the source code cannot be retrieved.
FIXED version with which we monkeypatch the stdlib to work around a bug."""
file = getsourcefile(object) or getfile(object)
# If the object is a frame, then trying to get the globals dict from its
# module won't work. Instead, the frame object itself has the globals
# dictionary.
globals_dict = None
if inspect.isframe(object):
# XXX: can this ever be false?
globals_dict = object.f_globals
else:
module = getmodule(object, file)
if module:
globals_dict = module.__dict__
lines = linecache.getlines(file, globals_dict)
if not lines:
raise IOError('could not get source code')
if ismodule(object):
return lines, 0
if isclass(object):
name = object.__name__
pat = re.compile(r'^(\s*)class\s*' + name + r'\b')
# make some effort to find the best matching class definition:
# use the one with the least indentation, which is the one
# that's most probably not inside a function definition.
candidates = []
for i in range(len(lines)):
match = pat.match(lines[i])
if match:
# if it's at toplevel, it's already the best one
if lines[i][0] == 'c':
return lines, i
# else add whitespace to candidate list
candidates.append((match.group(1), i))
if candidates:
# this will sort by whitespace, and by line number,
# less whitespace first
candidates.sort()
return lines, candidates[0][1]
else:
raise IOError('could not find class definition')
if ismethod(object):
object = object.im_func
if isfunction(object):
object = object.func_code
if istraceback(object):
object = object.tb_frame
if isframe(object):
object = object.f_code
if iscode(object):
if not hasattr(object, 'co_firstlineno'):
raise IOError('could not find function definition')
pat = re.compile(r'^(\s*def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)')
pmatch = pat.match
# fperez - fix: sometimes, co_firstlineno can give a number larger than
# the length of lines, which causes an error. Safeguard against that.
lnum = min(object.co_firstlineno,len(lines))-1
while lnum > 0:
if pmatch(lines[lnum]): break
lnum -= 1
return lines, lnum
raise IOError('could not find code object')
# Monkeypatch inspect to apply our bugfix. This code only works with py25
if sys.version_info[:2] >= (2,5):
inspect.findsource = findsource
def fix_frame_records_filenames(records):
"""Try to fix the filenames in each record from inspect.getinnerframes().
Particularly, modules loaded from within zip files have useless filenames
attached to their code object, and inspect.getinnerframes() just uses it.
"""
fixed_records = []
for frame, filename, line_no, func_name, lines, index in records:
# Look inside the frame's globals dictionary for __file__, which should
# be better.
better_fn = frame.f_globals.get('__file__', None)
if isinstance(better_fn, str):
# Check the type just in case someone did something weird with
# __file__. It might also be None if the error occurred during
# import.
filename = better_fn
fixed_records.append((frame, filename, line_no, func_name, lines, index))
return fixed_records
def _fixed_getinnerframes(etb, context=1,tb_offset=0):
import linecache
LNUM_POS, LINES_POS, INDEX_POS = 2, 4, 5
records = fix_frame_records_filenames(inspect.getinnerframes(etb, context))
# If the error is at the console, don't build any context, since it would
# otherwise produce 5 blank lines printed out (there is no file at the
# console)
rec_check = records[tb_offset:]
try:
rname = rec_check[0][1]
if rname == '<ipython console>' or rname.endswith('<string>'):
return rec_check
except IndexError:
pass
aux = traceback.extract_tb(etb)
assert len(records) == len(aux)
for i, (file, lnum, _, _) in zip(range(len(records)), aux):
maybeStart = lnum-1 - context//2
start = max(maybeStart, 0)
end = start + context
lines = linecache.getlines(file)[start:end]
buf = list(records[i])
buf[LNUM_POS] = lnum
buf[INDEX_POS] = lnum - 1 - start
buf[LINES_POS] = lines
records[i] = tuple(buf)
return records[tb_offset:]
# Helper function -- largely belongs to VerboseTB, but we need the same
# functionality to produce a pseudo verbose TB for SyntaxErrors, so that they
# can be recognized properly by ipython.el's py-traceback-line-re
# (SyntaxErrors have to be treated specially because they have no traceback)
_parser = PyColorize.Parser()
def _format_traceback_lines(lnum, index, lines, Colors, lvals=None,scheme=None):
numbers_width = INDENT_SIZE - 1
res = []
i = lnum - index
# This lets us get fully syntax-highlighted tracebacks.
if scheme is None:
ipinst = ipapi.get()
if ipinst is not None:
scheme = ipinst.colors
else:
scheme = DEFAULT_SCHEME
_line_format = _parser.format2
for line in lines:
# FIXME: we need to ensure the source is a pure string at this point,
# else the coloring code makes a royal mess. This is in need of a
# serious refactoring, so that all of the ultratb and PyColorize code
# is unicode-safe. So for now this is rather an ugly hack, but
# necessary to at least have readable tracebacks. Improvements welcome!
if type(line)==unicode:
line = line.encode('utf-8', 'replace')
new_line, err = _line_format(line, 'str', scheme)
if not err: line = new_line
if i == lnum:
# This is the line with the error
pad = numbers_width - len(str(i))
if pad >= 3:
marker = '-'*(pad-3) + '-> '
elif pad == 2:
marker = '> '
elif pad == 1:
marker = '>'
else:
marker = ''
num = marker + str(i)
line = '%s%s%s %s%s' %(Colors.linenoEm, num,
Colors.line, line, Colors.Normal)
else:
num = '%*s' % (numbers_width,i)
line = '%s%s%s %s' %(Colors.lineno, num,
Colors.Normal, line)
res.append(line)
if lvals and i == lnum:
res.append(lvals + '\n')
i = i + 1
return res
#---------------------------------------------------------------------------
# Module classes
class TBTools(object):
"""Basic tools used by all traceback printer classes."""
# Number of frames to skip when reporting tracebacks
tb_offset = 0
def __init__(self, color_scheme='NoColor', call_pdb=False, ostream=None):
# Whether to call the interactive pdb debugger after printing
# tracebacks or not
self.call_pdb = call_pdb
# Output stream to write to. Note that we store the original value in
# a private attribute and then make the public ostream a property, so
# that we can delay accessing io.stdout until runtime. The way
# things are written now, the io.stdout object is dynamically managed
# so a reference to it should NEVER be stored statically. This
# property approach confines this detail to a single location, and all
# subclasses can simply access self.ostream for writing.
self._ostream = ostream
# Create color table
self.color_scheme_table = exception_colors()
self.set_colors(color_scheme)
self.old_scheme = color_scheme # save initial value for toggles
if call_pdb:
self.pdb = debugger.Pdb(self.color_scheme_table.active_scheme_name)
else:
self.pdb = None
def _get_ostream(self):
"""Output stream that exceptions are written to.
Valid values are:
- None: the default, which means that IPython will dynamically resolve
to io.stdout. This ensures compatibility with most tools, including
Windows (where plain stdout doesn't recognize ANSI escapes).
- Any object with 'write' and 'flush' attributes.
"""
return io.stdout if self._ostream is None else self._ostream
def _set_ostream(self, val):
assert val is None or (hasattr(val, 'write') and hasattr(val, 'flush'))
self._ostream = val
ostream = property(_get_ostream, _set_ostream)
def set_colors(self,*args,**kw):
"""Shorthand access to the color table scheme selector method."""
# Set own color table
self.color_scheme_table.set_active_scheme(*args,**kw)
# for convenience, set Colors to the active scheme
self.Colors = self.color_scheme_table.active_colors
# Also set colors of debugger
if hasattr(self,'pdb') and self.pdb is not None:
self.pdb.set_colors(*args,**kw)
def color_toggle(self):
"""Toggle between the currently active color scheme and NoColor."""
if self.color_scheme_table.active_scheme_name == 'NoColor':
self.color_scheme_table.set_active_scheme(self.old_scheme)
self.Colors = self.color_scheme_table.active_colors
else:
self.old_scheme = self.color_scheme_table.active_scheme_name
self.color_scheme_table.set_active_scheme('NoColor')
self.Colors = self.color_scheme_table.active_colors
def stb2text(self, stb):
"""Convert a structured traceback (a list) to a string."""
return '\n'.join(stb)
def text(self, etype, value, tb, tb_offset=None, context=5):
"""Return formatted traceback.
Subclasses may override this if they add extra arguments.
"""
tb_list = self.structured_traceback(etype, value, tb,
tb_offset, context)
return self.stb2text(tb_list)
def structured_traceback(self, etype, evalue, tb, tb_offset=None,
context=5, mode=None):
"""Return a list of traceback frames.
Must be implemented by each class.
"""
raise NotImplementedError()
#---------------------------------------------------------------------------
class ListTB(TBTools):
"""Print traceback information from a traceback list, with optional color.
Calling: requires 3 arguments:
(etype, evalue, elist)
as would be obtained by:
etype, evalue, tb = sys.exc_info()
if tb:
elist = traceback.extract_tb(tb)
else:
elist = None
It can thus be used by programs which need to process the traceback before
printing (such as console replacements based on the code module from the
standard library).
Because they are meant to be called without a full traceback (only a
list), instances of this class can't call the interactive pdb debugger."""
def __init__(self,color_scheme = 'NoColor', call_pdb=False, ostream=None):
TBTools.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
ostream=ostream)
def __call__(self, etype, value, elist):
self.ostream.flush()
self.ostream.write(self.text(etype, value, elist))
self.ostream.write('\n')
def structured_traceback(self, etype, value, elist, tb_offset=None,
context=5):
"""Return a color formatted string with the traceback info.
Parameters
----------
etype : exception type
Type of the exception raised.
value : object
Data stored in the exception
elist : list
List of frames, see class docstring for details.
tb_offset : int, optional
Number of frames in the traceback to skip. If not given, the
instance value is used (set in constructor).
context : int, optional
Number of lines of context information to print.
Returns
-------
String with formatted exception.
"""
tb_offset = self.tb_offset if tb_offset is None else tb_offset
Colors = self.Colors
out_list = []
if elist:
if tb_offset and len(elist) > tb_offset:
elist = elist[tb_offset:]
out_list.append('Traceback %s(most recent call last)%s:' %
(Colors.normalEm, Colors.Normal) + '\n')
out_list.extend(self._format_list(elist))
# The exception info should be a single entry in the list.
lines = ''.join(self._format_exception_only(etype, value))
out_list.append(lines)
# Note: this code originally read:
## for line in lines[:-1]:
## out_list.append(" "+line)
## out_list.append(lines[-1])
# This means it was indenting everything but the last line by a little
# bit. I've disabled this for now, but if we see ugliness somewhre we
# can restore it.
return out_list
def _format_list(self, extracted_list):
"""Format a list of traceback entry tuples for printing.
Given a list of tuples as returned by extract_tb() or
extract_stack(), return a list of strings ready for printing.
Each string in the resulting list corresponds to the item with the
same index in the argument list. Each string ends in a newline;
the strings may contain internal newlines as well, for those items
whose source text line is not None.
Lifted almost verbatim from traceback.py
"""
Colors = self.Colors
list = []
for filename, lineno, name, line in extracted_list[:-1]:
item = ' File %s"%s"%s, line %s%d%s, in %s%s%s\n' % \
(Colors.filename, filename, Colors.Normal,
Colors.lineno, lineno, Colors.Normal,
Colors.name, name, Colors.Normal)
if line:
item = item + ' %s\n' % line.strip()
list.append(item)
# Emphasize the last entry
filename, lineno, name, line = extracted_list[-1]
item = '%s File %s"%s"%s, line %s%d%s, in %s%s%s%s\n' % \
(Colors.normalEm,
Colors.filenameEm, filename, Colors.normalEm,
Colors.linenoEm, lineno, Colors.normalEm,
Colors.nameEm, name, Colors.normalEm,
Colors.Normal)
if line:
item = item + '%s %s%s\n' % (Colors.line, line.strip(),
Colors.Normal)
list.append(item)
#from pprint import pformat; print 'LISTTB', pformat(list) # dbg
return list
def _format_exception_only(self, etype, value):
"""Format the exception part of a traceback.
The arguments are the exception type and value such as given by
sys.exc_info()[:2]. The return value is a list of strings, each ending
in a newline. Normally, the list contains a single string; however,
for SyntaxError exceptions, it contains several lines that (when
printed) display detailed information about where the syntax error
occurred. The message indicating which exception occurred is the
always last string in the list.
Also lifted nearly verbatim from traceback.py
"""
have_filedata = False
Colors = self.Colors
list = []
try:
stype = Colors.excName + etype.__name__ + Colors.Normal
except AttributeError:
stype = etype # String exceptions don't get special coloring
if value is None:
list.append( str(stype) + '\n')
else:
if etype is SyntaxError:
try:
msg, (filename, lineno, offset, line) = value
except:
have_filedata = False
else:
have_filedata = True
#print 'filename is',filename # dbg
if not filename: filename = "<string>"
list.append('%s File %s"%s"%s, line %s%d%s\n' % \
(Colors.normalEm,
Colors.filenameEm, filename, Colors.normalEm,
Colors.linenoEm, lineno, Colors.Normal ))
if line is not None:
i = 0
while i < len(line) and line[i].isspace():
i = i+1
list.append('%s %s%s\n' % (Colors.line,
line.strip(),
Colors.Normal))
if offset is not None:
s = ' '
for c in line[i:offset-1]:
if c.isspace():
s = s + c
else:
s = s + ' '
list.append('%s%s^%s\n' % (Colors.caret, s,
Colors.Normal) )
value = msg
s = self._some_str(value)
if s:
list.append('%s%s:%s %s\n' % (str(stype), Colors.excName,
Colors.Normal, s))
else:
list.append('%s\n' % str(stype))
# sync with user hooks
if have_filedata:
ipinst = ipapi.get()
if ipinst is not None:
ipinst.hooks.synchronize_with_editor(filename, lineno, 0)
return list
def get_exception_only(self, etype, value):
"""Only print the exception type and message, without a traceback.
Parameters
----------
etype : exception type
value : exception value
"""
return ListTB.structured_traceback(self, etype, value, [])
def show_exception_only(self, etype, evalue):
"""Only print the exception type and message, without a traceback.
Parameters
----------
etype : exception type
value : exception value
"""
# This method needs to use __call__ from *this* class, not the one from
# a subclass whose signature or behavior may be different
ostream = self.ostream
ostream.flush()
ostream.write('\n'.join(self.get_exception_only(etype, evalue)))
ostream.flush()
def _some_str(self, value):
# Lifted from traceback.py
try:
return str(value)
except:
return '<unprintable %s object>' % type(value).__name__
#----------------------------------------------------------------------------
class VerboseTB(TBTools):
"""A port of Ka-Ping Yee's cgitb.py module that outputs color text instead
of HTML. Requires inspect and pydoc. Crazy, man.
Modified version which optionally strips the topmost entries from the
traceback, to be used with alternate interpreters (because their own code
would appear in the traceback)."""
def __init__(self,color_scheme = 'Linux', call_pdb=False, ostream=None,
tb_offset=0, long_header=False, include_vars=True,
check_cache=None):
"""Specify traceback offset, headers and color scheme.
Define how many frames to drop from the tracebacks. Calling it with
tb_offset=1 allows use of this handler in interpreters which will have
their own code at the top of the traceback (VerboseTB will first
remove that frame before printing the traceback info)."""
TBTools.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
ostream=ostream)
self.tb_offset = tb_offset
self.long_header = long_header
self.include_vars = include_vars
# By default we use linecache.checkcache, but the user can provide a
# different check_cache implementation. This is used by the IPython
# kernel to provide tracebacks for interactive code that is cached,
# by a compiler instance that flushes the linecache but preserves its
# own code cache.
if check_cache is None:
check_cache = linecache.checkcache
self.check_cache = check_cache
def structured_traceback(self, etype, evalue, etb, tb_offset=None,
context=5):
"""Return a nice text document describing the traceback."""
tb_offset = self.tb_offset if tb_offset is None else tb_offset
# some locals
try:
etype = etype.__name__
except AttributeError:
pass
Colors = self.Colors # just a shorthand + quicker name lookup
ColorsNormal = Colors.Normal # used a lot
col_scheme = self.color_scheme_table.active_scheme_name
indent = ' '*INDENT_SIZE
em_normal = '%s\n%s%s' % (Colors.valEm, indent,ColorsNormal)
undefined = '%sundefined%s' % (Colors.em, ColorsNormal)
exc = '%s%s%s' % (Colors.excName,etype,ColorsNormal)
# some internal-use functions
def text_repr(value):
"""Hopefully pretty robust repr equivalent."""
# this is pretty horrible but should always return *something*
try:
return pydoc.text.repr(value)
except KeyboardInterrupt:
raise
except:
try:
return repr(value)
except KeyboardInterrupt:
raise
except:
try:
# all still in an except block so we catch
# getattr raising
name = getattr(value, '__name__', None)
if name:
# ick, recursion
return text_repr(name)
klass = getattr(value, '__class__', None)
if klass:
return '%s instance' % text_repr(klass)
except KeyboardInterrupt:
raise
except:
return 'UNRECOVERABLE REPR FAILURE'
def eqrepr(value, repr=text_repr): return '=%s' % repr(value)
def nullrepr(value, repr=text_repr): return ''
# meat of the code begins
try:
etype = etype.__name__
except AttributeError:
pass
if self.long_header:
# Header with the exception type, python version, and date
pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
date = time.ctime(time.time())
head = '%s%s%s\n%s%s%s\n%s' % (Colors.topline, '-'*75, ColorsNormal,
exc, ' '*(75-len(str(etype))-len(pyver)),
pyver, date.rjust(75) )
head += "\nA problem occured executing Python code. Here is the sequence of function"\
"\ncalls leading up to the error, with the most recent (innermost) call last."
else:
# Simplified header
head = '%s%s%s\n%s%s' % (Colors.topline, '-'*75, ColorsNormal,exc,
'Traceback (most recent call last)'.\
rjust(75 - len(str(etype)) ) )
frames = []
# Flush cache before calling inspect. This helps alleviate some of the
# problems with python 2.3's inspect.py.
##self.check_cache()
# Drop topmost frames if requested
try:
# Try the default getinnerframes and Alex's: Alex's fixes some
# problems, but it generates empty tracebacks for console errors
# (5 blanks lines) where none should be returned.
#records = inspect.getinnerframes(etb, context)[tb_offset:]
#print 'python records:', records # dbg
records = _fixed_getinnerframes(etb, context, tb_offset)
#print 'alex records:', records # dbg
except:
# FIXME: I've been getting many crash reports from python 2.3
# users, traceable to inspect.py. If I can find a small test-case
# to reproduce this, I should either write a better workaround or
# file a bug report against inspect (if that's the real problem).
# So far, I haven't been able to find an isolated example to
# reproduce the problem.
inspect_error()
traceback.print_exc(file=self.ostream)
info('\nUnfortunately, your original traceback can not be constructed.\n')
return ''
# build some color string templates outside these nested loops
tpl_link = '%s%%s%s' % (Colors.filenameEm,ColorsNormal)
tpl_call = 'in %s%%s%s%%s%s' % (Colors.vName, Colors.valEm,
ColorsNormal)
tpl_call_fail = 'in %s%%s%s(***failed resolving arguments***)%s' % \
(Colors.vName, Colors.valEm, ColorsNormal)
tpl_local_var = '%s%%s%s' % (Colors.vName, ColorsNormal)
tpl_global_var = '%sglobal%s %s%%s%s' % (Colors.em, ColorsNormal,
Colors.vName, ColorsNormal)
tpl_name_val = '%%s %s= %%s%s' % (Colors.valEm, ColorsNormal)
tpl_line = '%s%%s%s %%s' % (Colors.lineno, ColorsNormal)
tpl_line_em = '%s%%s%s %%s%s' % (Colors.linenoEm,Colors.line,
ColorsNormal)
# now, loop over all records printing context and info
abspath = os.path.abspath
for frame, file, lnum, func, lines, index in records:
#print '*** record:',file,lnum,func,lines,index # dbg
try:
file = file and abspath(file) or '?'
except OSError:
# if file is '<console>' or something not in the filesystem,
# the abspath call will throw an OSError. Just ignore it and
# keep the original file string.
pass
link = tpl_link % file
try:
args, varargs, varkw, locals = inspect.getargvalues(frame)
except:
# This can happen due to a bug in python2.3. We should be
# able to remove this try/except when 2.4 becomes a
# requirement. Bug details at http://python.org/sf/1005466
inspect_error()
traceback.print_exc(file=self.ostream)
info("\nIPython's exception reporting continues...\n")
if func == '?':
call = ''
else:
# Decide whether to include variable details or not
var_repr = self.include_vars and eqrepr or nullrepr
try:
call = tpl_call % (func,inspect.formatargvalues(args,
varargs, varkw,
locals,formatvalue=var_repr))
except KeyError:
# This happens in situations like errors inside generator
# expressions, where local variables are listed in the
# line, but can't be extracted from the frame. I'm not
# 100% sure this isn't actually a bug in inspect itself,
# but since there's no info for us to compute with, the
# best we can do is report the failure and move on. Here
# we must *not* call any traceback construction again,
# because that would mess up use of %debug later on. So we
# simply report the failure and move on. The only
# limitation will be that this frame won't have locals
# listed in the call signature. Quite subtle problem...
# I can't think of a good way to validate this in a unit
# test, but running a script consisting of:
# dict( (k,v.strip()) for (k,v) in range(10) )
# will illustrate the error, if this exception catch is
# disabled.
call = tpl_call_fail % func
# Initialize a list of names on the current line, which the
# tokenizer below will populate.
names = []
def tokeneater(token_type, token, start, end, line):
"""Stateful tokeneater which builds dotted names.
The list of names it appends to (from the enclosing scope) can
contain repeated composite names. This is unavoidable, since
there is no way to disambguate partial dotted structures until
the full list is known. The caller is responsible for pruning
the final list of duplicates before using it."""
# build composite names
if token == '.':
try:
names[-1] += '.'
# store state so the next token is added for x.y.z names
tokeneater.name_cont = True
return
except IndexError:
pass
if token_type == tokenize.NAME and token not in keyword.kwlist:
if tokeneater.name_cont:
# Dotted names
names[-1] += token
tokeneater.name_cont = False
else:
# Regular new names. We append everything, the caller
# will be responsible for pruning the list later. It's
# very tricky to try to prune as we go, b/c composite
# names can fool us. The pruning at the end is easy
# to do (or the caller can print a list with repeated
# names if so desired.
names.append(token)
elif token_type == tokenize.NEWLINE:
raise IndexError
# we need to store a bit of state in the tokenizer to build
# dotted names
tokeneater.name_cont = False
def linereader(file=file, lnum=[lnum], getline=linecache.getline):
line = getline(file, lnum[0])
lnum[0] += 1
return line
# Build the list of names on this line of code where the exception
# occurred.
try:
# This builds the names list in-place by capturing it from the
# enclosing scope.
tokenize.tokenize(linereader, tokeneater)
except IndexError:
# signals exit of tokenizer
pass
except tokenize.TokenError,msg:
_m = ("An unexpected error occurred while tokenizing input\n"
"The following traceback may be corrupted or invalid\n"
"The error message is: %s\n" % msg)
error(_m)
# prune names list of duplicates, but keep the right order
unique_names = uniq_stable(names)
# Start loop over vars
lvals = []
if self.include_vars:
for name_full in unique_names:
name_base = name_full.split('.',1)[0]
if name_base in frame.f_code.co_varnames:
if locals.has_key(name_base):
try:
value = repr(eval(name_full,locals))
except:
value = undefined
else:
value = undefined
name = tpl_local_var % name_full
else:
if frame.f_globals.has_key(name_base):
try:
value = repr(eval(name_full,frame.f_globals))
except:
value = undefined
else:
value = undefined
name = tpl_global_var % name_full
lvals.append(tpl_name_val % (name,value))
if lvals:
lvals = '%s%s' % (indent,em_normal.join(lvals))
else:
lvals = ''
level = '%s %s\n' % (link,call)
if index is None:
frames.append(level)
else:
frames.append('%s%s' % (level,''.join(
_format_traceback_lines(lnum,index,lines,Colors,lvals,
col_scheme))))
# Get (safely) a string form of the exception info
try:
etype_str,evalue_str = map(str,(etype,evalue))
except:
# User exception is improperly defined.
etype,evalue = str,sys.exc_info()[:2]
etype_str,evalue_str = map(str,(etype,evalue))
# ... and format it
exception = ['%s%s%s: %s' % (Colors.excName, etype_str,
ColorsNormal, evalue_str)]
if type(evalue) is types.InstanceType:
try:
names = [w for w in dir(evalue) if isinstance(w, basestring)]
except:
# Every now and then, an object with funny inernals blows up
# when dir() is called on it. We do the best we can to report
# the problem and continue
_m = '%sException reporting error (object with broken dir())%s:'
exception.append(_m % (Colors.excName,ColorsNormal))
etype_str,evalue_str = map(str,sys.exc_info()[:2])
exception.append('%s%s%s: %s' % (Colors.excName,etype_str,
ColorsNormal, evalue_str))
names = []
for name in names:
value = text_repr(getattr(evalue, name))
exception.append('\n%s%s = %s' % (indent, name, value))
# vds: >>
if records:
filepath, lnum = records[-1][1:3]
#print "file:", str(file), "linenb", str(lnum) # dbg
filepath = os.path.abspath(filepath)
ipinst = ipapi.get()
if ipinst is not None:
ipinst.hooks.synchronize_with_editor(filepath, lnum, 0)
# vds: <<
# return all our info assembled as a single string
# return '%s\n\n%s\n%s' % (head,'\n'.join(frames),''.join(exception[0]) )
return [head] + frames + [''.join(exception[0])]
def debugger(self,force=False):
"""Call up the pdb debugger if desired, always clean up the tb
reference.
Keywords:
- force(False): by default, this routine checks the instance call_pdb
flag and does not actually invoke the debugger if the flag is false.
The 'force' option forces the debugger to activate even if the flag
is false.
If the call_pdb flag is set, the pdb interactive debugger is
invoked. In all cases, the self.tb reference to the current traceback
is deleted to prevent lingering references which hamper memory
management.
Note that each call to pdb() does an 'import readline', so if your app
requires a special setup for the readline completers, you'll have to
fix that by hand after invoking the exception handler."""
if force or self.call_pdb:
if self.pdb is None:
self.pdb = debugger.Pdb(
self.color_scheme_table.active_scheme_name)
# the system displayhook may have changed, restore the original
# for pdb
display_trap = DisplayTrap(hook=sys.__displayhook__)
with display_trap:
self.pdb.reset()
# Find the right frame so we don't pop up inside ipython itself
if hasattr(self,'tb') and self.tb is not None:
etb = self.tb
else:
etb = self.tb = sys.last_traceback
while self.tb is not None and self.tb.tb_next is not None:
self.tb = self.tb.tb_next
if etb and etb.tb_next:
etb = etb.tb_next
self.pdb.botframe = etb.tb_frame
self.pdb.interaction(self.tb.tb_frame, self.tb)
if hasattr(self,'tb'):
del self.tb
def handler(self, info=None):
(etype, evalue, etb) = info or sys.exc_info()
self.tb = etb
ostream = self.ostream
ostream.flush()
ostream.write(self.text(etype, evalue, etb))
ostream.write('\n')
ostream.flush()
# Changed so an instance can just be called as VerboseTB_inst() and print
# out the right info on its own.
def __call__(self, etype=None, evalue=None, etb=None):
"""This hook can replace sys.excepthook (for Python 2.1 or higher)."""
if etb is None:
self.handler()
else:
self.handler((etype, evalue, etb))
try:
self.debugger()
except KeyboardInterrupt:
print "\nKeyboardInterrupt"
#----------------------------------------------------------------------------
class FormattedTB(VerboseTB, ListTB):
"""Subclass ListTB but allow calling with a traceback.
It can thus be used as a sys.excepthook for Python > 2.1.
Also adds 'Context' and 'Verbose' modes, not available in ListTB.
Allows a tb_offset to be specified. This is useful for situations where
one needs to remove a number of topmost frames from the traceback (such as
occurs with python programs that themselves execute other python code,
like Python shells). """
def __init__(self, mode='Plain', color_scheme='Linux', call_pdb=False,
ostream=None,
tb_offset=0, long_header=False, include_vars=False,
check_cache=None):
# NEVER change the order of this list. Put new modes at the end:
self.valid_modes = ['Plain','Context','Verbose']
self.verbose_modes = self.valid_modes[1:3]
VerboseTB.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
ostream=ostream, tb_offset=tb_offset,
long_header=long_header, include_vars=include_vars,
check_cache=check_cache)
# Different types of tracebacks are joined with different separators to
# form a single string. They are taken from this dict
self._join_chars = dict(Plain='', Context='\n', Verbose='\n')
# set_mode also sets the tb_join_char attribute
self.set_mode(mode)
def _extract_tb(self,tb):
if tb:
return traceback.extract_tb(tb)
else:
return None
def structured_traceback(self, etype, value, tb, tb_offset=None, context=5):
tb_offset = self.tb_offset if tb_offset is None else tb_offset
mode = self.mode
if mode in self.verbose_modes:
# Verbose modes need a full traceback
return VerboseTB.structured_traceback(
self, etype, value, tb, tb_offset, context
)
else:
# We must check the source cache because otherwise we can print
# out-of-date source code.
self.check_cache()
# Now we can extract and format the exception
elist = self._extract_tb(tb)
return ListTB.structured_traceback(
self, etype, value, elist, tb_offset, context
)
def stb2text(self, stb):
"""Convert a structured traceback (a list) to a string."""
return self.tb_join_char.join(stb)
def set_mode(self,mode=None):
"""Switch to the desired mode.
If mode is not specified, cycles through the available modes."""
if not mode:
new_idx = ( self.valid_modes.index(self.mode) + 1 ) % \
len(self.valid_modes)
self.mode = self.valid_modes[new_idx]
elif mode not in self.valid_modes:
raise ValueError, 'Unrecognized mode in FormattedTB: <'+mode+'>\n'\
'Valid modes: '+str(self.valid_modes)
else:
self.mode = mode
# include variable details only in 'Verbose' mode
self.include_vars = (self.mode == self.valid_modes[2])
# Set the join character for generating text tracebacks
self.tb_join_char = self._join_chars[self.mode]
# some convenient shorcuts
def plain(self):
self.set_mode(self.valid_modes[0])
def context(self):
self.set_mode(self.valid_modes[1])
def verbose(self):
self.set_mode(self.valid_modes[2])
#----------------------------------------------------------------------------
class AutoFormattedTB(FormattedTB):
"""A traceback printer which can be called on the fly.
It will find out about exceptions by itself.
A brief example:
AutoTB = AutoFormattedTB(mode = 'Verbose',color_scheme='Linux')
try:
...
except:
AutoTB() # or AutoTB(out=logfile) where logfile is an open file object
"""
def __call__(self,etype=None,evalue=None,etb=None,
out=None,tb_offset=None):
"""Print out a formatted exception traceback.
Optional arguments:
- out: an open file-like object to direct output to.
- tb_offset: the number of frames to skip over in the stack, on a
per-call basis (this overrides temporarily the instance's tb_offset
given at initialization time. """
if out is None:
out = self.ostream
out.flush()
out.write(self.text(etype, evalue, etb, tb_offset))
out.write('\n')
out.flush()
# FIXME: we should remove the auto pdb behavior from here and leave
# that to the clients.
try:
self.debugger()
except KeyboardInterrupt:
print "\nKeyboardInterrupt"
def structured_traceback(self, etype=None, value=None, tb=None,
tb_offset=None, context=5):
if etype is None:
etype,value,tb = sys.exc_info()
self.tb = tb
return FormattedTB.structured_traceback(
self, etype, value, tb, tb_offset, context)
#---------------------------------------------------------------------------
# A simple class to preserve Nathan's original functionality.
class ColorTB(FormattedTB):
"""Shorthand to initialize a FormattedTB in Linux colors mode."""
def __init__(self,color_scheme='Linux',call_pdb=0):
FormattedTB.__init__(self,color_scheme=color_scheme,
call_pdb=call_pdb)
class SyntaxTB(ListTB):
"""Extension which holds some state: the last exception value"""
def __init__(self,color_scheme = 'NoColor'):
ListTB.__init__(self,color_scheme)
self.last_syntax_error = None
def __call__(self, etype, value, elist):
self.last_syntax_error = value
ListTB.__call__(self,etype,value,elist)
def clear_err_state(self):
"""Return the current error state and clear it"""
e = self.last_syntax_error
self.last_syntax_error = None
return e
def stb2text(self, stb):
"""Convert a structured traceback (a list) to a string."""
return ''.join(stb)
#----------------------------------------------------------------------------
# module testing (minimal)
if __name__ == "__main__":
def spam(c, (d, e)):
x = c + d
y = c * d
foo(x, y)
def foo(a, b, bar=1):
eggs(a, b + bar)
def eggs(f, g, z=globals()):
h = f + g
i = f - g
return h / i
print ''
print '*** Before ***'
try:
print spam(1, (2, 3))
except:
traceback.print_exc()
print ''
handler = ColorTB()
print '*** ColorTB ***'
try:
print spam(1, (2, 3))
except:
apply(handler, sys.exc_info() )
print ''
handler = VerboseTB()
print '*** VerboseTB ***'
try:
print spam(1, (2, 3))
except:
apply(handler, sys.exc_info() )
print ''
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