#
# Copyright (c) 2012, Albert Zeyer, www.az2000.de
# All rights reserved.
# file created 2011-04-15
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# This is a simple replacement for the standard Python exception handler (sys.excepthook).
# In addition to what the standard handler does, it also prints all referenced variables
# (no matter if local, global or builtin) of the code line of each stack frame.
# See below for some examples and some example output.
# https://github.com/albertz/py_better_exchook
import sys
import os
import keyword
pykeywords = set(keyword.kwlist)
[docs]
def parse_py_statement(line):
state = 0
curtoken = ""
spaces = " \t\n"
ops = ".,;:+-*/%&=|(){}[]^<>"
i = 0
def _escape_char(c):
if c == "n": return "\n"
elif c == "t": return "\t"
else: return c
while i < len(line):
c = line[i]
i += 1
if state == 0:
if c in spaces: pass
elif c in ops: yield ("op", c)
elif c == "#": state = 6
elif c == "\"": state = 1
elif c == "'": state = 2
else:
curtoken = c
state = 3
elif state == 1: # string via "
if c == "\\": state = 4
elif c == "\"":
yield ("str", curtoken)
curtoken = ""
state = 0
else: curtoken += c
elif state == 2: # string via '
if c == "\\": state = 5
elif c == "'":
yield ("str", curtoken)
curtoken = ""
state = 0
else: curtoken += c
elif state == 3: # identifier
if c in spaces + ops + "#\"'":
yield ("id", curtoken)
curtoken = ""
state = 0
i -= 1
else: curtoken += c
elif state == 4: # escape in "
curtoken += _escape_char(c)
state = 1
elif state == 5: # escape in '
curtoken += _escape_char(c)
state = 2
elif state == 6: # comment
curtoken += c
if state == 3: yield ("id", curtoken)
elif state == 6: yield ("comment", curtoken)
[docs]
def grep_full_py_identifiers(tokens):
global pykeywords
tokens = list(tokens)
i = 0
while i < len(tokens):
tokentype, token = tokens[i]
i += 1
if tokentype != "id": continue
while i+1 < len(tokens) and tokens[i] == ("op", ".") and tokens[i+1][0] == "id":
token += "." + tokens[i+1][1]
i += 2
if token == "": continue
if token in pykeywords: continue
if token[0] in ".0123456789": continue
yield token
[docs]
def output(s, out=sys.stdout): print(s, file=out)
[docs]
def output_limit():
return 300
[docs]
def pretty_print(obj):
s = repr(obj)
limit = output_limit()
if len(s) > limit:
s = s[:limit - 3] + "..."
extra_info = pp_extra_info(obj)
if extra_info != "": s += ", " + extra_info
return s
[docs]
def fallback_findfile(filename):
mods = [ m for m in sys.modules.values() if m and hasattr(m, "__file__") and filename in m.__file__ ]
if len(mods) == 0: return None
altfn = mods[0].__file__
if altfn[-4:-1] == ".py": altfn = altfn[:-1] # *.pyc or whatever
return altfn
[docs]
def better_exchook(etype, value, tb, out=sys.stdout):
output('Traceback (most recent call last):', out=out)
allLocals,allGlobals = {},{}
try:
import linecache
limit = None
if hasattr(sys, 'tracebacklimit'):
limit = sys.tracebacklimit
n = 0
_tb = tb
def _resolveIdentifier(namespace, id):
obj = namespace[id[0]]
for part in id[1:]:
obj = getattr(obj, part)
return obj
def _trySet(old, prefix, func):
if old is not None: return old
try: return prefix + func()
except KeyError: return old
except Exception as e:
return prefix + "!" + e.__class__.__name__ + ": " + str(e)
while _tb is not None and (limit is None or n < limit):
f = _tb.tb_frame
allLocals.update(f.f_locals)
allGlobals.update(f.f_globals)
lineno = _tb.tb_lineno
co = f.f_code
filename = co.co_filename
name = co.co_name
output(' File "%s", line %d, in %s' % (filename,lineno,name), out=out)
if not os.path.isfile(filename):
altfn = fallback_findfile(filename)
if altfn:
output(" -- couldn't find file, trying this instead: " + altfn, out=out)
filename = altfn
linecache.checkcache(filename)
line = linecache.getline(filename, lineno, f.f_globals)
if line:
line = line.strip()
output(' line: ' + line, out=out)
output(' locals:', out=out)
alreadyPrintedLocals = set()
for tokenstr in grep_full_py_identifiers(parse_py_statement(line)):
splittedtoken = tuple(tokenstr.split("."))
for token in map(lambda i: splittedtoken[0:i], range(1, len(splittedtoken) + 1)):
if token in alreadyPrintedLocals: continue
tokenvalue = None
tokenvalue = _trySet(tokenvalue, "<local> ", lambda: pretty_print(_resolveIdentifier(f.f_locals, token)))
tokenvalue = _trySet(tokenvalue, "<global> ", lambda: pretty_print(_resolveIdentifier(f.f_globals, token)))
tokenvalue = _trySet(tokenvalue, "<builtin> ", lambda: pretty_print(_resolveIdentifier(f.f_builtins, token)))
tokenvalue = tokenvalue or "<not found>"
output(' ' + ".".join(token) + " = " + tokenvalue, out=out)
alreadyPrintedLocals.add(token)
if len(alreadyPrintedLocals) == 0: output(" no locals", out=out)
else:
output(' -- code not available --', out=out)
_tb = _tb.tb_next
n += 1
except Exception:
output("ERROR: cannot get more detailed exception info because:", out=out)
import traceback
for l in traceback.format_exc().split("\n"): output(" " + l, out=out)
output("simple traceback:", out=out)
traceback.print_tb(tb, None, out)
import types
def _some_str(value):
try:
return str(value)
except Exception:
return '<unprintable %s object>' % type(value).__name__
def _format_final_exc_line(etype, value):
valuestr = _some_str(value)
if value is None or not valuestr:
line = "%s" % etype
else:
line = f"{etype}: {valuestr}"
return line
if isinstance(etype, BaseException) or etype is None or type(etype) is str:
output(_format_final_exc_line(etype, value), out=out)
else:
output(_format_final_exc_line(etype.__name__, value), out=out)
[docs]
def install():
sys.excepthook = better_exchook