Source code for linkcheck.better_exchook2

#
# 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
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# (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 pp_extra_info(obj, depthlimit = 3): s = [] if hasattr(obj, "__len__"): try: if type(obj) in (bytes,str,list,tuple,dict) and len(obj) <= 5: pass # don't print len in this case else: s += ["len = " + str(obj.__len__())] except Exception: pass if depthlimit > 0 and hasattr(obj, "__getitem__"): try: if type(obj) in (bytes,str): pass # doesn't make sense to get subitems here else: subobj = obj.__getitem__(0) extra_info = pp_extra_info(subobj, depthlimit - 1) if extra_info != "": s += ["_[0]: {" + extra_info + "}"] except Exception: pass return ", ".join(s)
[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 (hasattr(types, "InstanceType") and isinstance(etype, types.InstanceType)) 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