#! /usr/bin/env python3"""The Python Debugger Pdb=======================To use the debugger in its simplest form:>>> import pdb>>> pdb.run('<a statement>')The debugger's prompt is '(Pdb) '. This will stop in the firstfunction call in <a statement>.Alternatively, if a statement terminated with an unhandled exception,you can use pdb's post-mortem facility to inspect the contents of thetraceback:>>> <a statement><exception traceback>>>> import pdb>>> pdb.pm()The commands recognized by the debugger are listed in the nextsection. Most can be abbreviated as indicated; e.g., h(elp) meansthat 'help' can be typed as 'h' or 'help' (but not as 'he' or 'hel',nor as 'H' or 'Help' or 'HELP'). Optional arguments are enclosed insquare brackets. Alternatives in the command syntax are separatedby a vertical bar (|).A blank line repeats the previous command literally, except for'list', where it lists the next 11 lines.Commands that the debugger doesn't recognize are assumed to be Pythonstatements and are executed in the context of the program beingdebugged. Python statements can also be prefixed with an exclamationpoint ('!'). This is a powerful way to inspect the program beingdebugged; it is even possible to change variables or call functions.When an exception occurs in such a statement, the exception name isprinted but the debugger's state is not changed.The debugger supports aliases, which can save typing. And aliases canhave parameters (see the alias help entry) which allows one a certainlevel of adaptability to the context under examination.Multiple commands may be entered on a single line, separated by thepair ';;'. No intelligence is applied to separating the commands; theinput is split at the first ';;', even if it is in the middle of aquoted string.If a file ".pdbrc" exists in your home directory or in the currentdirectory, it is read in and executed as if it had been typed at thedebugger prompt. This is particularly useful for aliases. If bothfiles exist, the one in the home directory is read first and aliasesdefined there can be overridden by the local file. This behavior can bedisabled by passing the "readrc=False" argument to the Pdb constructor.Aside from aliases, the debugger is not directly programmable; but itis implemented as a class from which you can derive your own debuggerclass, which you can make as fancy as you like.Debugger commands================="""# NOTE: the actual command documentation is collected from docstrings of the# commands and is appended to __doc__ after the class has been defined.import osimport reimport sysimport cmdimport bdbimport disimport codeimport globimport pprintimport signalimport inspectimport tracebackimport linecacheclass Restart(Exception):"""Causes a debugger to be restarted for the debugged python program."""pass__all__ = ["run", "pm", "Pdb", "runeval", "runctx", "runcall", "set_trace","post_mortem", "help"]def find_function(funcname, filename):cre = re.compile(r'def\s+%s\s*[(]' % re.escape(funcname))try:fp = open(filename)except OSError:return None# consumer of this info expects the first line to be 1with fp:for lineno, line in enumerate(fp, start=1):if cre.match(line):return funcname, filename, linenoreturn Nonedef getsourcelines(obj):lines, lineno = inspect.findsource(obj)if inspect.isframe(obj) and obj.f_globals is obj.f_locals:# must be a module frame: do not try to cut a block out of itreturn lines, 1elif inspect.ismodule(obj):return lines, 1return inspect.getblock(lines[lineno:]), lineno+1def lasti2lineno(code, lasti):linestarts = list(dis.findlinestarts(code))linestarts.reverse()for i, lineno in linestarts:if lasti >= i:return linenoreturn 0class _rstr(str):"""String that doesn't quote its repr."""def __repr__(self):return self# Interaction prompt line will separate file and call info from code# text using value of line_prefix string. A newline and arrow may# be to your liking. You can set it once pdb is imported using the# command "pdb.line_prefix = '\n% '".# line_prefix = ': ' # Use this to get the old situation backline_prefix = '\n-> ' # Probably a better defaultclass Pdb(bdb.Bdb, cmd.Cmd):_previous_sigint_handler = Nonedef __init__(self, completekey='tab', stdin=None, stdout=None, skip=None,nosigint=False, readrc=True):bdb.Bdb.__init__(self, skip=skip)cmd.Cmd.__init__(self, completekey, stdin, stdout)if stdout:self.use_rawinput = 0self.prompt = '(Pdb) 'self.aliases = {}self.displaying = {}self.mainpyfile = ''self._wait_for_mainpyfile = Falseself.tb_lineno = {}# Try to load readline if it existstry:import readline# remove some common file name delimitersreadline.set_completer_delims(' \t\n`@#$%^&*()=+[{]}\\|;:\'",<>?')except ImportError:passself.allow_kbdint = Falseself.nosigint = nosigint# Read $HOME/.pdbrc and ./.pdbrcself.rcLines = []if readrc:if 'HOME' in os.environ:envHome = os.environ['HOME']try:with open(os.path.join(envHome, ".pdbrc")) as rcFile:self.rcLines.extend(rcFile)except OSError:passtry:with open(".pdbrc") as rcFile:self.rcLines.extend(rcFile)except OSError:passself.commands = {} # associates a command list to breakpoint numbersself.commands_doprompt = {} # for each bp num, tells if the prompt# must be disp. after execing the cmd listself.commands_silent = {} # for each bp num, tells if the stack trace# must be disp. after execing the cmd listself.commands_defining = False # True while in the process of defining# a command listself.commands_bnum = None # The breakpoint number for which we are# defining a listdef sigint_handler(self, signum, frame):if self.allow_kbdint:raise KeyboardInterruptself.message("\nProgram interrupted. (Use 'cont' to resume).")self.set_step()self.set_trace(frame)def reset(self):bdb.Bdb.reset(self)self.forget()def forget(self):self.lineno = Noneself.stack = []self.curindex = 0self.curframe = Noneself.tb_lineno.clear()def setup(self, f, tb):self.forget()self.stack, self.curindex = self.get_stack(f, tb)while tb:# when setting up post-mortem debugging with a traceback, save all# the original line numbers to be displayed along the current line# numbers (which can be different, e.g. due to finally clauses)lineno = lasti2lineno(tb.tb_frame.f_code, tb.tb_lasti)self.tb_lineno[tb.tb_frame] = linenotb = tb.tb_nextself.curframe = self.stack[self.curindex][0]# The f_locals dictionary is updated from the actual frame# locals whenever the .f_locals accessor is called, so we# cache it here to ensure that modifications are not overwritten.self.curframe_locals = self.curframe.f_localsreturn self.execRcLines()# Can be executed earlier than 'setup' if desireddef execRcLines(self):if not self.rcLines:return# local copy because of recursionrcLines = self.rcLinesrcLines.reverse()# execute every line only onceself.rcLines = []while rcLines:line = rcLines.pop().strip()if line and line[0] != '#':if self.onecmd(line):# if onecmd returns True, the command wants to exit# from the interaction, save leftover rc lines# to execute before next interactionself.rcLines += reversed(rcLines)return True# Override Bdb methodsdef user_call(self, frame, argument_list):"""This method is called when there is the remote possibilitythat we ever need to stop in this function."""if self._wait_for_mainpyfile:returnif self.stop_here(frame):self.message('--Call--')self.interaction(frame, None)def user_line(self, frame):"""This function is called when we stop or break at this line."""if self._wait_for_mainpyfile:if (self.mainpyfile != self.canonic(frame.f_code.co_filename)or frame.f_lineno <= 0):returnself._wait_for_mainpyfile = Falseif self.bp_commands(frame):self.interaction(frame, None)def bp_commands(self, frame):"""Call every command that was set for the current active breakpoint(if there is one).Returns True if the normal interaction function must be called,False otherwise."""# self.currentbp is set in bdb in Bdb.break_here if a breakpoint was hitif getattr(self, "currentbp", False) and \self.currentbp in self.commands:currentbp = self.currentbpself.currentbp = 0lastcmd_back = self.lastcmdself.setup(frame, None)for line in self.commands[currentbp]:self.onecmd(line)self.lastcmd = lastcmd_backif not self.commands_silent[currentbp]:self.print_stack_entry(self.stack[self.curindex])if self.commands_doprompt[currentbp]:self._cmdloop()self.forget()returnreturn 1def user_return(self, frame, return_value):"""This function is called when a return trap is set here."""if self._wait_for_mainpyfile:returnframe.f_locals['__return__'] = return_valueself.message('--Return--')self.interaction(frame, None)def user_exception(self, frame, exc_info):"""This function is called if an exception occurs,but only if we are to stop at or just below this level."""if self._wait_for_mainpyfile:returnexc_type, exc_value, exc_traceback = exc_infoframe.f_locals['__exception__'] = exc_type, exc_value# An 'Internal StopIteration' exception is an exception debug event# issued by the interpreter when handling a subgenerator run with# 'yield from' or a generator controlled by a for loop. No exception has# actually occurred in this case. The debugger uses this debug event to# stop when the debuggee is returning from such generators.prefix = 'Internal ' if (not exc_tracebackand exc_type is StopIteration) else ''self.message('%s%s' % (prefix,traceback.format_exception_only(exc_type, exc_value)[-1].strip()))self.interaction(frame, exc_traceback)# General interaction functiondef _cmdloop(self):while True:try:# keyboard interrupts allow for an easy way to cancel# the current command, so allow them during interactive inputself.allow_kbdint = Trueself.cmdloop()self.allow_kbdint = Falsebreakexcept KeyboardInterrupt:self.message('--KeyboardInterrupt--')# Called before loop, handles display expressionsdef preloop(self):displaying = self.displaying.get(self.curframe)if displaying:for expr, oldvalue in displaying.items():newvalue = self._getval_except(expr)# check for identity first; this prevents custom __eq__ to# be called at every loop, and also prevents instances whose# fields are changed to be displayedif newvalue is not oldvalue and newvalue != oldvalue:displaying[expr] = newvalueself.message('display %s: %r [old: %r]' %(expr, newvalue, oldvalue))def interaction(self, frame, traceback):# Restore the previous signal handler at the Pdb prompt.if Pdb._previous_sigint_handler:signal.signal(signal.SIGINT, Pdb._previous_sigint_handler)Pdb._previous_sigint_handler = Noneif self.setup(frame, traceback):# no interaction desired at this time (happens if .pdbrc contains# a command like "continue")self.forget()returnself.print_stack_entry(self.stack[self.curindex])self._cmdloop()self.forget()def displayhook(self, obj):"""Custom displayhook for the exec in default(), which preventsassignment of the _ variable in the builtins."""# reproduce the behavior of the standard displayhook, not printing Noneif obj is not None:self.message(repr(obj))def default(self, line):if line[:1] == '!': line = line[1:]locals = self.curframe_localsglobals = self.curframe.f_globalstry:code = compile(line + '\n', '<stdin>', 'single')save_stdout = sys.stdoutsave_stdin = sys.stdinsave_displayhook = sys.displayhooktry:sys.stdin = self.stdinsys.stdout = self.stdoutsys.displayhook = self.displayhookexec(code, globals, locals)finally:sys.stdout = save_stdoutsys.stdin = save_stdinsys.displayhook = save_displayhookexcept:exc_info = sys.exc_info()[:2]self.error(traceback.format_exception_only(*exc_info)[-1].strip())def precmd(self, line):"""Handle alias expansion and ';;' separator."""if not line.strip():return lineargs = line.split()while args[0] in self.aliases:line = self.aliases[args[0]]ii = 1for tmpArg in args[1:]:line = line.replace("%" + str(ii),tmpArg)ii += 1line = line.replace("%*", ' '.join(args[1:]))args = line.split()# split into ';;' separated commands# unless it's an alias commandif args[0] != 'alias':marker = line.find(';;')if marker >= 0:# queue up everything after markernext = line[marker+2:].lstrip()self.cmdqueue.append(next)line = line[:marker].rstrip()return linedef onecmd(self, line):"""Interpret the argument as though it had been typed in responseto the prompt.Checks whether this line is typed at the normal prompt or ina breakpoint command list definition."""if not self.commands_defining:return cmd.Cmd.onecmd(self, line)else:return self.handle_command_def(line)def handle_command_def(self, line):"""Handles one command line during command list definition."""cmd, arg, line = self.parseline(line)if not cmd:returnif cmd == 'silent':self.commands_silent[self.commands_bnum] = Truereturn # continue to handle other cmd def in the cmd listelif cmd == 'end':self.cmdqueue = []return 1 # end of cmd listcmdlist = self.commands[self.commands_bnum]if arg:cmdlist.append(cmd+' '+arg)else:cmdlist.append(cmd)# Determine if we must stoptry:func = getattr(self, 'do_' + cmd)except AttributeError:func = self.default# one of the resuming commandsif func.__name__ in self.commands_resuming:self.commands_doprompt[self.commands_bnum] = Falseself.cmdqueue = []return 1return# interface abstraction functionsdef message(self, msg):print(msg, file=self.stdout)def error(self, msg):print('***', msg, file=self.stdout)# Generic completion functions. Individual complete_foo methods can be# assigned below to one of these functions.def _complete_location(self, text, line, begidx, endidx):# Complete a file/module/function location for break/tbreak/clear.if line.strip().endswith((':', ',')):# Here comes a line number or a condition which we can't complete.return []# First, try to find matching functions (i.e. expressions).try:ret = self._complete_expression(text, line, begidx, endidx)except Exception:ret = []# Then, try to complete file names as well.globs = glob.glob(text + '*')for fn in globs:if os.path.isdir(fn):ret.append(fn + '/')elif os.path.isfile(fn) and fn.lower().endswith(('.py', '.pyw')):ret.append(fn + ':')return retdef _complete_bpnumber(self, text, line, begidx, endidx):# Complete a breakpoint number. (This would be more helpful if we could# display additional info along with the completions, such as file/line# of the breakpoint.)return [str(i) for i, bp in enumerate(bdb.Breakpoint.bpbynumber)if bp is not None and str(i).startswith(text)]def _complete_expression(self, text, line, begidx, endidx):# Complete an arbitrary expression.if not self.curframe:return []# Collect globals and locals. It is usually not really sensible to also# complete builtins, and they clutter the namespace quite heavily, so we# leave them out.ns = self.curframe.f_globals.copy()ns.update(self.curframe_locals)if '.' in text:# Walk an attribute chain up to the last part, similar to what# rlcompleter does. This will bail if any of the parts are not# simple attribute access, which is what we want.dotted = text.split('.')try:obj = ns[dotted[0]]for part in dotted[1:-1]:obj = getattr(obj, part)except (KeyError, AttributeError):return []prefix = '.'.join(dotted[:-1]) + '.'return [prefix + n for n in dir(obj) if n.startswith(dotted[-1])]else:# Complete a simple name.return [n for n in ns.keys() if n.startswith(text)]# Command definitions, called by cmdloop()# The argument is the remaining string on the command line# Return true to exit from the command loopdef do_commands(self, arg):"""commands [bpnumber](com) ...(com) end(Pdb)Specify a list of commands for breakpoint number bpnumber.The commands themselves are entered on the following lines.Type a line containing just 'end' to terminate the commands.The commands are executed when the breakpoint is hit.To remove all commands from a breakpoint, type commands andfollow it immediately with end; that is, give no commands.With no bpnumber argument, commands refers to the lastbreakpoint set.You can use breakpoint commands to start your program upagain. Simply use the continue command, or step, or any othercommand that resumes execution.Specifying any command resuming execution (currently continue,step, next, return, jump, quit and their abbreviations)terminates the command list (as if that command wasimmediately followed by end). This is because any time youresume execution (even with a simple next or step), you mayencounter another breakpoint -- which could have its owncommand list, leading to ambiguities about which list toexecute.If you use the 'silent' command in the command list, the usualmessage about stopping at a breakpoint is not printed. Thismay be desirable for breakpoints that are to print a specificmessage and then continue. If none of the other commandsprint anything, you will see no sign that the breakpoint wasreached."""if not arg:bnum = len(bdb.Breakpoint.bpbynumber) - 1else:try:bnum = int(arg)except:self.error("Usage: commands [bnum]\n ...\n end")returnself.commands_bnum = bnum# Save old definitions for the case of a keyboard interrupt.if bnum in self.commands:old_command_defs = (self.commands[bnum],self.commands_doprompt[bnum],self.commands_silent[bnum])else:old_command_defs = Noneself.commands[bnum] = []self.commands_doprompt[bnum] = Trueself.commands_silent[bnum] = Falseprompt_back = self.promptself.prompt = '(com) 'self.commands_defining = Truetry:self.cmdloop()except KeyboardInterrupt:# Restore old definitions.if old_command_defs:self.commands[bnum] = old_command_defs[0]self.commands_doprompt[bnum] = old_command_defs[1]self.commands_silent[bnum] = old_command_defs[2]else:del self.commands[bnum]del self.commands_doprompt[bnum]del self.commands_silent[bnum]self.error('command definition aborted, old commands restored')finally:self.commands_defining = Falseself.prompt = prompt_backcomplete_commands = _complete_bpnumberdef do_break(self, arg, temporary = 0):"""b(reak) [ ([filename:]lineno | function) [, condition] ]Without argument, list all breaks.With a line number argument, set a break at this line in thecurrent file. With a function name, set a break at the firstexecutable line of that function. If a second argument ispresent, it is a string specifying an expression which mustevaluate to true before the breakpoint is honored.The line number may be prefixed with a filename and a colon,to specify a breakpoint in another file (probably one thathasn't been loaded yet). The file is searched for onsys.path; the .py suffix may be omitted."""if not arg:if self.breaks: # There's at least oneself.message("Num Type Disp Enb Where")for bp in bdb.Breakpoint.bpbynumber:if bp:self.message(bp.bpformat())return# parse arguments; comma has lowest precedence# and cannot occur in filenamefilename = Nonelineno = Nonecond = Nonecomma = arg.find(',')if comma > 0:# parse stuff after comma: "condition"cond = arg[comma+1:].lstrip()arg = arg[:comma].rstrip()# parse stuff before comma: [filename:]lineno | functioncolon = arg.rfind(':')funcname = Noneif colon >= 0:filename = arg[:colon].rstrip()f = self.lookupmodule(filename)if not f:self.error('%r not found from sys.path' % filename)returnelse:filename = farg = arg[colon+1:].lstrip()try:lineno = int(arg)except ValueError:self.error('Bad lineno: %s' % arg)returnelse:# no colon; can be lineno or functiontry:lineno = int(arg)except ValueError:try:func = eval(arg,self.curframe.f_globals,self.curframe_locals)except:func = argtry:if hasattr(func, '__func__'):func = func.__func__code = func.__code__#use co_name to identify the bkpt (function names#could be aliased, but co_name is invariant)funcname = code.co_namelineno = code.co_firstlinenofilename = code.co_filenameexcept:# last thing to try(ok, filename, ln) = self.lineinfo(arg)if not ok:self.error('The specified object %r is not a function ''or was not found along sys.path.' % arg)returnfuncname = ok # ok contains a function namelineno = int(ln)if not filename:filename = self.defaultFile()# Check for reasonable breakpointline = self.checkline(filename, lineno)if line:# now set the break pointerr = self.set_break(filename, line, temporary, cond, funcname)if err:self.error(err)else:bp = self.get_breaks(filename, line)[-1]self.message("Breakpoint %d at %s:%d" %(bp.number, bp.file, bp.line))# To be overridden in derived debuggersdef defaultFile(self):"""Produce a reasonable default."""filename = self.curframe.f_code.co_filenameif filename == '<string>' and self.mainpyfile:filename = self.mainpyfilereturn filenamedo_b = do_breakcomplete_break = _complete_locationcomplete_b = _complete_locationdef do_tbreak(self, arg):"""tbreak [ ([filename:]lineno | function) [, condition] ]Same arguments as break, but sets a temporary breakpoint: itis automatically deleted when first hit."""self.do_break(arg, 1)complete_tbreak = _complete_locationdef lineinfo(self, identifier):failed = (None, None, None)# Input is identifier, may be in single quotesidstring = identifier.split("'")if len(idstring) == 1:# not in single quotesid = idstring[0].strip()elif len(idstring) == 3:# quotedid = idstring[1].strip()else:return failedif id == '': return failedparts = id.split('.')# Protection for derived debuggersif parts[0] == 'self':del parts[0]if len(parts) == 0:return failed# Best first guess at file to look atfname = self.defaultFile()if len(parts) == 1:item = parts[0]else:# More than one part.# First is module, second is method/classf = self.lookupmodule(parts[0])if f:fname = fitem = parts[1]answer = find_function(item, fname)return answer or faileddef checkline(self, filename, lineno):"""Check whether specified line seems to be executable.Return `lineno` if it is, 0 if not (e.g. a docstring, comment, blankline or EOF). Warning: testing is not comprehensive."""# this method should be callable before starting debugging, so default# to "no globals" if there is no current frameglobs = self.curframe.f_globals if hasattr(self, 'curframe') else Noneline = linecache.getline(filename, lineno, globs)if not line:self.message('End of file')return 0line = line.strip()# Don't allow setting breakpoint at a blank lineif (not line or (line[0] == '#') or(line[:3] == '"""') or line[:3] == "'''"):self.error('Blank or comment')return 0return linenodef do_enable(self, arg):"""enable bpnumber [bpnumber ...]Enables the breakpoints given as a space separated list ofbreakpoint numbers."""args = arg.split()for i in args:try:bp = self.get_bpbynumber(i)except ValueError as err:self.error(err)else:bp.enable()self.message('Enabled %s' % bp)complete_enable = _complete_bpnumberdef do_disable(self, arg):"""disable bpnumber [bpnumber ...]Disables the breakpoints given as a space separated list ofbreakpoint numbers. Disabling a breakpoint means it cannotcause the program to stop execution, but unlike clearing abreakpoint, it remains in the list of breakpoints and can be(re-)enabled."""args = arg.split()for i in args:try:bp = self.get_bpbynumber(i)except ValueError as err:self.error(err)else:bp.disable()self.message('Disabled %s' % bp)complete_disable = _complete_bpnumberdef do_condition(self, arg):"""condition bpnumber [condition]Set a new condition for the breakpoint, an expression whichmust evaluate to true before the breakpoint is honored. Ifcondition is absent, any existing condition is removed; i.e.,the breakpoint is made unconditional."""args = arg.split(' ', 1)try:cond = args[1]except IndexError:cond = Nonetry:bp = self.get_bpbynumber(args[0].strip())except IndexError:self.error('Breakpoint number expected')except ValueError as err:self.error(err)else:bp.cond = condif not cond:self.message('Breakpoint %d is now unconditional.' % bp.number)else:self.message('New condition set for breakpoint %d.' % bp.number)complete_condition = _complete_bpnumberdef do_ignore(self, arg):"""ignore bpnumber [count]Set the ignore count for the given breakpoint number. Ifcount is omitted, the ignore count is set to 0. A breakpointbecomes active when the ignore count is zero. When non-zero,the count is decremented each time the breakpoint is reachedand the breakpoint is not disabled and any associatedcondition evaluates to true."""args = arg.split()try:count = int(args[1].strip())except:count = 0try:bp = self.get_bpbynumber(args[0].strip())except IndexError:self.error('Breakpoint number expected')except ValueError as err:self.error(err)else:bp.ignore = countif count > 0:if count > 1:countstr = '%d crossings' % countelse:countstr = '1 crossing'self.message('Will ignore next %s of breakpoint %d.' %(countstr, bp.number))else:self.message('Will stop next time breakpoint %d is reached.'% bp.number)complete_ignore = _complete_bpnumberdef do_clear(self, arg):"""cl(ear) filename:lineno\ncl(ear) [bpnumber [bpnumber...]]With a space separated list of breakpoint numbers, clearthose breakpoints. Without argument, clear all breaks (butfirst ask confirmation). With a filename:lineno argument,clear all breaks at that line in that file."""if not arg:try:reply = input('Clear all breaks? ')except EOFError:reply = 'no'reply = reply.strip().lower()if reply in ('y', 'yes'):bplist = [bp for bp in bdb.Breakpoint.bpbynumber if bp]self.clear_all_breaks()for bp in bplist:self.message('Deleted %s' % bp)returnif ':' in arg:# Make sure it works for "clear C:\foo\bar.py:12"i = arg.rfind(':')filename = arg[:i]arg = arg[i+1:]try:lineno = int(arg)except ValueError:err = "Invalid line number (%s)" % argelse:bplist = self.get_breaks(filename, lineno)err = self.clear_break(filename, lineno)if err:self.error(err)else:for bp in bplist:self.message('Deleted %s' % bp)returnnumberlist = arg.split()for i in numberlist:try:bp = self.get_bpbynumber(i)except ValueError as err:self.error(err)else:self.clear_bpbynumber(i)self.message('Deleted %s' % bp)do_cl = do_clear # 'c' is already an abbreviation for 'continue'complete_clear = _complete_locationcomplete_cl = _complete_locationdef do_where(self, arg):"""w(here)Print a stack trace, with the most recent frame at the bottom.An arrow indicates the "current frame", which determines thecontext of most commands. 'bt' is an alias for this command."""self.print_stack_trace()do_w = do_wheredo_bt = do_wheredef _select_frame(self, number):assert 0 <= number < len(self.stack)self.curindex = numberself.curframe = self.stack[self.curindex][0]self.curframe_locals = self.curframe.f_localsself.print_stack_entry(self.stack[self.curindex])self.lineno = Nonedef do_up(self, arg):"""u(p) [count]Move the current frame count (default one) levels up in thestack trace (to an older frame)."""if self.curindex == 0:self.error('Oldest frame')returntry:count = int(arg or 1)except ValueError:self.error('Invalid frame count (%s)' % arg)returnif count < 0:newframe = 0else:newframe = max(0, self.curindex - count)self._select_frame(newframe)do_u = do_updef do_down(self, arg):"""d(own) [count]Move the current frame count (default one) levels down in thestack trace (to a newer frame)."""if self.curindex + 1 == len(self.stack):self.error('Newest frame')returntry:count = int(arg or 1)except ValueError:self.error('Invalid frame count (%s)' % arg)returnif count < 0:newframe = len(self.stack) - 1else:newframe = min(len(self.stack) - 1, self.curindex + count)self._select_frame(newframe)do_d = do_downdef do_until(self, arg):"""unt(il) [lineno]Without argument, continue execution until the line with anumber greater than the current one is reached. With a linenumber, continue execution until a line with a number greateror equal to that is reached. In both cases, also stop whenthe current frame returns."""if arg:try:lineno = int(arg)except ValueError:self.error('Error in argument: %r' % arg)returnif lineno <= self.curframe.f_lineno:self.error('"until" line number is smaller than current ''line number')returnelse:lineno = Noneself.set_until(self.curframe, lineno)return 1do_unt = do_untildef do_step(self, arg):"""s(tep)Execute the current line, stop at the first possible occasion(either in a function that is called or in the currentfunction)."""self.set_step()return 1do_s = do_stepdef do_next(self, arg):"""n(ext)Continue execution until the next line in the current functionis reached or it returns."""self.set_next(self.curframe)return 1do_n = do_nextdef do_run(self, arg):"""run [args...]Restart the debugged python program. If a string is suppliedit is split with "shlex", and the result is used as the newsys.argv. History, breakpoints, actions and debugger optionsare preserved. "restart" is an alias for "run"."""if arg:import shlexargv0 = sys.argv[0:1]sys.argv = shlex.split(arg)sys.argv[:0] = argv0# this is caught in the main debugger loopraise Restartdo_restart = do_rundef do_return(self, arg):"""r(eturn)Continue execution until the current function returns."""self.set_return(self.curframe)return 1do_r = do_returndef do_continue(self, arg):"""c(ont(inue))Continue execution, only stop when a breakpoint is encountered."""if not self.nosigint:try:Pdb._previous_sigint_handler = \signal.signal(signal.SIGINT, self.sigint_handler)except ValueError:# ValueError happens when do_continue() is invoked from# a non-main thread in which case we just continue without# SIGINT set. Would printing a message here (once) make# sense?passself.set_continue()return 1do_c = do_cont = do_continuedef do_jump(self, arg):"""j(ump) linenoSet the next line that will be executed. Only available inthe bottom-most frame. This lets you jump back and executecode again, or jump forward to skip code that you don't wantto run.It should be noted that not all jumps are allowed -- forinstance it is not possible to jump into the middle of afor loop or out of a finally clause."""if self.curindex + 1 != len(self.stack):self.error('You can only jump within the bottom frame')returntry:arg = int(arg)except ValueError:self.error("The 'jump' command requires a line number")else:try:# Do the jump, fix up our copy of the stack, and display the# new positionself.curframe.f_lineno = argself.stack[self.curindex] = self.stack[self.curindex][0], argself.print_stack_entry(self.stack[self.curindex])except ValueError as e:self.error('Jump failed: %s' % e)do_j = do_jumpdef do_debug(self, arg):"""debug codeEnter a recursive debugger that steps through the codeargument (which is an arbitrary expression or statement to beexecuted in the current environment)."""sys.settrace(None)globals = self.curframe.f_globalslocals = self.curframe_localsp = Pdb(self.completekey, self.stdin, self.stdout)p.prompt = "(%s) " % self.prompt.strip()self.message("ENTERING RECURSIVE DEBUGGER")try:sys.call_tracing(p.run, (arg, globals, locals))except Exception:exc_info = sys.exc_info()[:2]self.error(traceback.format_exception_only(*exc_info)[-1].strip())self.message("LEAVING RECURSIVE DEBUGGER")sys.settrace(self.trace_dispatch)self.lastcmd = p.lastcmdcomplete_debug = _complete_expressiondef do_quit(self, arg):"""q(uit)\nexitQuit from the debugger. The program being executed is aborted."""self._user_requested_quit = Trueself.set_quit()return 1do_q = do_quitdo_exit = do_quitdef do_EOF(self, arg):"""EOFHandles the receipt of EOF as a command."""self.message('')self._user_requested_quit = Trueself.set_quit()return 1def do_args(self, arg):"""a(rgs)Print the argument list of the current function."""co = self.curframe.f_codedict = self.curframe_localsn = co.co_argcount + co.co_kwonlyargcountif co.co_flags & inspect.CO_VARARGS: n = n+1if co.co_flags & inspect.CO_VARKEYWORDS: n = n+1for i in range(n):name = co.co_varnames[i]if name in dict:self.message('%s = %r' % (name, dict[name]))else:self.message('%s = *** undefined ***' % (name,))do_a = do_argsdef do_retval(self, arg):"""retvalPrint the return value for the last return of a function."""if '__return__' in self.curframe_locals:self.message(repr(self.curframe_locals['__return__']))else:self.error('Not yet returned!')do_rv = do_retvaldef _getval(self, arg):try:return eval(arg, self.curframe.f_globals, self.curframe_locals)except:exc_info = sys.exc_info()[:2]self.error(traceback.format_exception_only(*exc_info)[-1].strip())raisedef _getval_except(self, arg, frame=None):try:if frame is None:return eval(arg, self.curframe.f_globals, self.curframe_locals)else:return eval(arg, frame.f_globals, frame.f_locals)except:exc_info = sys.exc_info()[:2]err = traceback.format_exception_only(*exc_info)[-1].strip()return _rstr('** raised %s **' % err)def do_p(self, arg):"""p expressionPrint the value of the expression."""try:self.message(repr(self._getval(arg)))except:passdef do_pp(self, arg):"""pp expressionPretty-print the value of the expression."""try:self.message(pprint.pformat(self._getval(arg)))except:passcomplete_print = _complete_expressioncomplete_p = _complete_expressioncomplete_pp = _complete_expressiondef do_list(self, arg):"""l(ist) [first [,last] | .]List source code for the current file. Without arguments,list 11 lines around the current line or continue the previouslisting. With . as argument, list 11 lines around the currentline. With one argument, list 11 lines starting at that line.With two arguments, list the given range; if the secondargument is less than the first, it is a count.The current line in the current frame is indicated by "->".If an exception is being debugged, the line where theexception was originally raised or propagated is indicated by">>", if it differs from the current line."""self.lastcmd = 'list'last = Noneif arg and arg != '.':try:if ',' in arg:first, last = arg.split(',')first = int(first.strip())last = int(last.strip())if last < first:# assume it's a countlast = first + lastelse:first = int(arg.strip())first = max(1, first - 5)except ValueError:self.error('Error in argument: %r' % arg)returnelif self.lineno is None or arg == '.':first = max(1, self.curframe.f_lineno - 5)else:first = self.lineno + 1if last is None:last = first + 10filename = self.curframe.f_code.co_filenamebreaklist = self.get_file_breaks(filename)try:lines = linecache.getlines(filename, self.curframe.f_globals)self._print_lines(lines[first-1:last], first, breaklist,self.curframe)self.lineno = min(last, len(lines))if len(lines) < last:self.message('[EOF]')except KeyboardInterrupt:passdo_l = do_listdef do_longlist(self, arg):"""longlist | llList the whole source code for the current function or frame."""filename = self.curframe.f_code.co_filenamebreaklist = self.get_file_breaks(filename)try:lines, lineno = getsourcelines(self.curframe)except OSError as err:self.error(err)returnself._print_lines(lines, lineno, breaklist, self.curframe)do_ll = do_longlistdef do_source(self, arg):"""source expressionTry to get source code for the given object and display it."""try:obj = self._getval(arg)except:returntry:lines, lineno = getsourcelines(obj)except (OSError, TypeError) as err:self.error(err)returnself._print_lines(lines, lineno)complete_source = _complete_expressiondef _print_lines(self, lines, start, breaks=(), frame=None):"""Print a range of lines."""if frame:current_lineno = frame.f_linenoexc_lineno = self.tb_lineno.get(frame, -1)else:current_lineno = exc_lineno = -1for lineno, line in enumerate(lines, start):s = str(lineno).rjust(3)if len(s) < 4:s += ' 'if lineno in breaks:s += 'B'else:s += ' 'if lineno == current_lineno:s += '->'elif lineno == exc_lineno:s += '>>'self.message(s + '\t' + line.rstrip())def do_whatis(self, arg):"""whatis argPrint the type of the argument."""try:value = self._getval(arg)except:# _getval() already printed the errorreturncode = None# Is it a function?try:code = value.__code__except Exception:passif code:self.message('Function %s' % code.co_name)return# Is it an instance method?try:code = value.__func__.__code__except Exception:passif code:self.message('Method %s' % code.co_name)return# Is it a class?if value.__class__ is type:self.message('Class %s.%s' % (value.__module__, value.__qualname__))return# None of the above...self.message(type(value))complete_whatis = _complete_expressiondef do_display(self, arg):"""display [expression]Display the value of the expression if it changed, each time executionstops in the current frame.Without expression, list all display expressions for the current frame."""if not arg:self.message('Currently displaying:')for item in self.displaying.get(self.curframe, {}).items():self.message('%s: %r' % item)else:val = self._getval_except(arg)self.displaying.setdefault(self.curframe, {})[arg] = valself.message('display %s: %r' % (arg, val))complete_display = _complete_expressiondef do_undisplay(self, arg):"""undisplay [expression]Do not display the expression any more in the current frame.Without expression, clear all display expressions for the current frame."""if arg:try:del self.displaying.get(self.curframe, {})[arg]except KeyError:self.error('not displaying %s' % arg)else:self.displaying.pop(self.curframe, None)def complete_undisplay(self, text, line, begidx, endidx):return [e for e in self.displaying.get(self.curframe, {})if e.startswith(text)]def do_interact(self, arg):"""interactStart an interactive interpreter whose global namespacecontains all the (global and local) names found in the current scope."""ns = self.curframe.f_globals.copy()ns.update(self.curframe_locals)code.interact("*interactive*", local=ns)def do_alias(self, arg):"""alias [name [command [parameter parameter ...] ]]Create an alias called 'name' that executes 'command'. Thecommand must *not* be enclosed in quotes. Replaceableparameters can be indicated by %1, %2, and so on, while %* isreplaced by all the parameters. If no command is given, thecurrent alias for name is shown. If no name is given, allaliases are listed.Aliases may be nested and can contain anything that can belegally typed at the pdb prompt. Note! You *can* overrideinternal pdb commands with aliases! Those internal commandsare then hidden until the alias is removed. Aliasing isrecursively applied to the first word of the command line; allother words in the line are left alone.As an example, here are two useful aliases (especially whenplaced in the .pdbrc file):# Print instance variables (usage "pi classInst")alias pi for k in %1.__dict__.keys(): print("%1.",k,"=",%1.__dict__[k])# Print instance variables in selfalias ps pi self"""args = arg.split()if len(args) == 0:keys = sorted(self.aliases.keys())for alias in keys:self.message("%s = %s" % (alias, self.aliases[alias]))returnif args[0] in self.aliases and len(args) == 1:self.message("%s = %s" % (args[0], self.aliases[args[0]]))else:self.aliases[args[0]] = ' '.join(args[1:])def do_unalias(self, arg):"""unalias nameDelete the specified alias."""args = arg.split()if len(args) == 0: returnif args[0] in self.aliases:del self.aliases[args[0]]def complete_unalias(self, text, line, begidx, endidx):return [a for a in self.aliases if a.startswith(text)]# List of all the commands making the program resume execution.commands_resuming = ['do_continue', 'do_step', 'do_next', 'do_return','do_quit', 'do_jump']# Print a traceback starting at the top stack frame.# The most recently entered frame is printed last;# this is different from dbx and gdb, but consistent with# the Python interpreter's stack trace.# It is also consistent with the up/down commands (which are# compatible with dbx and gdb: up moves towards 'main()'# and down moves towards the most recent stack frame).def print_stack_trace(self):try:for frame_lineno in self.stack:self.print_stack_entry(frame_lineno)except KeyboardInterrupt:passdef print_stack_entry(self, frame_lineno, prompt_prefix=line_prefix):frame, lineno = frame_linenoif frame is self.curframe:prefix = '> 'else:prefix = ' 'self.message(prefix +self.format_stack_entry(frame_lineno, prompt_prefix))# Provide helpdef do_help(self, arg):"""h(elp)Without argument, print the list of available commands.With a command name as argument, print help about that command."help pdb" shows the full pdb documentation."help exec" gives help on the ! command."""if not arg:return cmd.Cmd.do_help(self, arg)try:try:topic = getattr(self, 'help_' + arg)return topic()except AttributeError:command = getattr(self, 'do_' + arg)except AttributeError:self.error('No help for %r' % arg)else:if sys.flags.optimize >= 2:self.error('No help for %r; please do not run Python with -OO ''if you need command help' % arg)returnself.message(command.__doc__.rstrip())do_h = do_helpdef help_exec(self):"""(!) statementExecute the (one-line) statement in the context of the currentstack frame. The exclamation point can be omitted unless thefirst word of the statement resembles a debugger command. Toassign to a global variable you must always prefix the commandwith a 'global' command, e.g.:(Pdb) global list_options; list_options = ['-l'](Pdb)"""self.message((self.help_exec.__doc__ or '').strip())def help_pdb(self):help()# other helper functionsdef lookupmodule(self, filename):"""Helper function for break/clear parsing -- may be overridden.lookupmodule() translates (possibly incomplete) file or module nameinto an absolute file name."""if os.path.isabs(filename) and os.path.exists(filename):return filenamef = os.path.join(sys.path[0], filename)if os.path.exists(f) and self.canonic(f) == self.mainpyfile:return froot, ext = os.path.splitext(filename)if ext == '':filename = filename + '.py'if os.path.isabs(filename):return filenamefor dirname in sys.path:while os.path.islink(dirname):dirname = os.readlink(dirname)fullname = os.path.join(dirname, filename)if os.path.exists(fullname):return fullnamereturn Nonedef _runmodule(self, module_name):self._wait_for_mainpyfile = Trueself._user_requested_quit = Falseimport runpymod_name, mod_spec, code = runpy._get_module_details(module_name)self.mainpyfile = self.canonic(code.co_filename)import __main____main__.__dict__.clear()__main__.__dict__.update({"__name__": "__main__","__file__": self.mainpyfile,"__package__": mod_spec.parent,"__loader__": mod_spec.loader,"__spec__": mod_spec,"__builtins__": __builtins__,})self.run(code)def _runscript(self, filename):# The script has to run in __main__ namespace (or imports from# __main__ will break).## So we clear up the __main__ and set several special variables# (this gets rid of pdb's globals and cleans old variables on restarts).import __main____main__.__dict__.clear()__main__.__dict__.update({"__name__" : "__main__","__file__" : filename,"__builtins__": __builtins__,})# When bdb sets tracing, a number of call and line events happens# BEFORE debugger even reaches user's code (and the exact sequence of# events depends on python version). So we take special measures to# avoid stopping before we reach the main script (see user_line and# user_call for details).self._wait_for_mainpyfile = Trueself.mainpyfile = self.canonic(filename)self._user_requested_quit = Falsewith open(filename, "rb") as fp:statement = "exec(compile(%r, %r, 'exec'))" % \(fp.read(), self.mainpyfile)self.run(statement)# Collect all command help into docstring, if not run with -OOif __doc__ is not None:# unfortunately we can't guess this order from the class definition_help_order = ['help', 'where', 'down', 'up', 'break', 'tbreak', 'clear', 'disable','enable', 'ignore', 'condition', 'commands', 'step', 'next', 'until','jump', 'return', 'retval', 'run', 'continue', 'list', 'longlist','args', 'p', 'pp', 'whatis', 'source', 'display', 'undisplay','interact', 'alias', 'unalias', 'debug', 'quit',]for _command in _help_order:__doc__ += getattr(Pdb, 'do_' + _command).__doc__.strip() + '\n\n'__doc__ += Pdb.help_exec.__doc__del _help_order, _command# Simplified interfacedef run(statement, globals=None, locals=None):Pdb().run(statement, globals, locals)def runeval(expression, globals=None, locals=None):return Pdb().runeval(expression, globals, locals)def runctx(statement, globals, locals):# B/W compatibilityrun(statement, globals, locals)def runcall(*args, **kwds):return Pdb().runcall(*args, **kwds)def set_trace(*, header=None):pdb = Pdb()if header is not None:pdb.message(header)pdb.set_trace(sys._getframe().f_back)# Post-Mortem interfacedef post_mortem(t=None):# handling the defaultif t is None:# sys.exc_info() returns (type, value, traceback) if an exception is# being handled, otherwise it returns Nonet = sys.exc_info()[2]if t is None:raise ValueError("A valid traceback must be passed if no ""exception is being handled")p = Pdb()p.reset()p.interaction(None, t)def pm():post_mortem(sys.last_traceback)# Main program for testingTESTCMD = 'import x; x.main()'def test():run(TESTCMD)# print helpdef help():import pydocpydoc.pager(__doc__)_usage = """\usage: pdb.py [-c command] ... [-m module | pyfile] [arg] ...Debug the Python program given by pyfile. Alternatively,an executable module or package to debug can be specified usingthe -m switch.Initial commands are read from .pdbrc files in your home directoryand in the current directory, if they exist. Commands supplied with-c are executed after commands from .pdbrc files.To let the script run until an exception occurs, use "-c continue".To let the script run up to a given line X in the debugged file, use"-c 'until X'"."""def main():import getoptopts, args = getopt.getopt(sys.argv[1:], 'mhc:', ['--help', '--command='])if not args:print(_usage)sys.exit(2)commands = []run_as_module = Falsefor opt, optarg in opts:if opt in ['-h', '--help']:print(_usage)sys.exit()elif opt in ['-c', '--command']:commands.append(optarg)elif opt in ['-m']:run_as_module = Truemainpyfile = args[0] # Get script filenameif not run_as_module and not os.path.exists(mainpyfile):print('Error:', mainpyfile, 'does not exist')sys.exit(1)sys.argv[:] = args # Hide "pdb.py" and pdb options from argument list# Replace pdb's dir with script's dir in front of module search path.if not run_as_module:sys.path[0] = os.path.dirname(mainpyfile)# Note on saving/restoring sys.argv: it's a good idea when sys.argv was# modified by the script being debugged. It's a bad idea when it was# changed by the user from the command line. There is a "restart" command# which allows explicit specification of command line arguments.pdb = Pdb()pdb.rcLines.extend(commands)while True:try:if run_as_module:pdb._runmodule(mainpyfile)else:pdb._runscript(mainpyfile)if pdb._user_requested_quit:breakprint("The program finished and will be restarted")except Restart:print("Restarting", mainpyfile, "with arguments:")print("\t" + " ".join(args))except SystemExit:# In most cases SystemExit does not warrant a post-mortem session.print("The program exited via sys.exit(). Exit status:", end=' ')print(sys.exc_info()[1])except SyntaxError:traceback.print_exc()sys.exit(1)except:traceback.print_exc()print("Uncaught exception. Entering post mortem debugging")print("Running 'cont' or 'step' will restart the program")t = sys.exc_info()[2]pdb.interaction(None, t)print("Post mortem debugger finished. The " + mainpyfile +" will be restarted")# When invoked as main program, invoke the debugger on a scriptif __name__ == '__main__':import pdbpdb.main()
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