""" The Python Debugger Pdb ======================= To use the debugger in its simplest form: >>> import pdb >>> pdb.run('') The debugger's prompt is '(Pdb) '. This will stop in the first function call in . Alternatively, if a statement terminated with an unhandled exception, you can use pdb's post-mortem facility to inspect the contents of the traceback: >>> >>> import pdb >>> pdb.pm() The commands recognized by the debugger are listed in the next section. Most can be abbreviated as indicated; e.g., h(elp) means that '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 in square brackets. Alternatives in the command syntax are separated by 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 Python statements and are executed in the context of the program being debugged. Python statements can also be prefixed with an exclamation point ('!'). This is a powerful way to inspect the program being debugged; it is even possible to change variables or call functions. When an exception occurs in such a statement, the exception name is printed but the debugger's state is not changed. The debugger supports aliases, which can save typing. And aliases can have parameters (see the alias help entry) which allows one a certain level of adaptability to the context under examination. Multiple commands may be entered on a single line, separated by the pair ';;'. No intelligence is applied to separating the commands; the input is split at the first ';;', even if it is in the middle of a quoted string. If a file ".pdbrc" exists in your home directory or in the current directory, it is read in and executed as if it had been typed at the debugger prompt. This is particularly useful for aliases. If both files exist, the one in the home directory is read first and aliases defined there can be overridden by the local file. This behavior can be disabled by passing the "readrc=False" argument to the Pdb constructor. Aside from aliases, the debugger is not directly programmable; but it is implemented as a class from which you can derive your own debugger class, 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 os import io import re import sys import cmd import bdb import dis import code import glob import token import types import codeop import pprint import signal import inspect import textwrap import tokenize import traceback import linecache import _colorize from contextlib import contextmanager from rlcompleter import Completer from types import CodeType class 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_first_executable_line(code): """ Try to find the first executable line of the code object. Equivalently, find the line number of the instruction that's after RESUME Return code.co_firstlineno if no executable line is found. """ prev = None for instr in dis.get_instructions(code): if prev is not None and prev.opname == 'RESUME': if instr.positions.lineno is not None: return instr.positions.lineno return code.co_firstlineno prev = instr return code.co_firstlineno def find_function(funcname, filename): cre = re.compile(r'def\s+%s\s*[(]' % re.escape(funcname)) try: fp = tokenize.open(filename) except OSError: lines = linecache.getlines(filename) if not lines: return None fp = io.StringIO(''.join(lines)) funcdef = "" funcstart = None # consumer of this info expects the first line to be 1 with fp: for lineno, line in enumerate(fp, start=1): if cre.match(line): funcstart, funcdef = lineno, line elif funcdef: funcdef += line if funcdef: try: funccode = compile(funcdef, filename, 'exec').co_consts[0] except SyntaxError: continue lineno_offset = find_first_executable_line(funccode) return funcname, filename, funcstart + lineno_offset - 1 return None def lasti2lineno(code, lasti): linestarts = list(dis.findlinestarts(code)) linestarts.reverse() for i, lineno in linestarts: if lasti >= i: return lineno return 0 class _rstr(str): """String that doesn't quote its repr.""" def __repr__(self): return self class _ExecutableTarget: filename: str code: CodeType | str namespace: dict class _ScriptTarget(_ExecutableTarget): def __init__(self, target): self._target = os.path.realpath(target) if not os.path.exists(self._target): print(f'Error: {target} does not exist') sys.exit(1) if os.path.isdir(self._target): print(f'Error: {target} is a directory') sys.exit(1) # If safe_path(-P) is not set, sys.path[0] is the directory # of pdb, and we should replace it with the directory of the script if not sys.flags.safe_path: sys.path[0] = os.path.dirname(self._target) def __repr__(self): return self._target @property def filename(self): return self._target @property def code(self): # Open the file each time because the file may be modified with io.open_code(self._target) as fp: return f"exec(compile({fp.read()!r}, {self._target!r}, 'exec'))" @property def namespace(self): return dict( __name__='__main__', __file__=self._target, __builtins__=__builtins__, __spec__=None, ) class _ModuleTarget(_ExecutableTarget): def __init__(self, target): self._target = target import runpy try: _, self._spec, self._code = runpy._get_module_details(self._target) except ImportError as e: print(f"ImportError: {e}") sys.exit(1) except Exception: traceback.print_exc() sys.exit(1) def __repr__(self): return self._target @property def filename(self): return self._code.co_filename @property def code(self): return self._code @property def namespace(self): return dict( __name__='__main__', __file__=os.path.normcase(os.path.abspath(self.filename)), __package__=self._spec.parent, __loader__=self._spec.loader, __spec__=self._spec, __builtins__=__builtins__, ) class _ZipTarget(_ExecutableTarget): def __init__(self, target): import runpy self._target = os.path.realpath(target) sys.path.insert(0, self._target) try: _, self._spec, self._code = runpy._get_main_module_details() except ImportError as e: print(f"ImportError: {e}") sys.exit(1) except Exception: traceback.print_exc() sys.exit(1) def __repr__(self): return self._target @property def filename(self): return self._code.co_filename @property def code(self): return self._code @property def namespace(self): return dict( __name__='__main__', __file__=os.path.normcase(os.path.abspath(self.filename)), __package__=self._spec.parent, __loader__=self._spec.loader, __spec__=self._spec, __builtins__=__builtins__, ) class _PdbInteractiveConsole(code.InteractiveConsole): def __init__(self, ns, message): self._message = message super().__init__(locals=ns, local_exit=True) def write(self, data): self._message(data, end='') # 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 back line_prefix = '\n-> ' # Probably a better default class Pdb(bdb.Bdb, cmd.Cmd): _previous_sigint_handler = None # Limit the maximum depth of chained exceptions, we should be handling cycles, # but in case there are recursions, we stop at 999. MAX_CHAINED_EXCEPTION_DEPTH = 999 _file_mtime_table = {} _last_pdb_instance = None def __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) sys.audit("pdb.Pdb") if stdout: self.use_rawinput = 0 self.prompt = '(Pdb) ' self.aliases = {} self.displaying = {} self.mainpyfile = '' self._wait_for_mainpyfile = False self.tb_lineno = {} # Try to load readline if it exists try: import readline # remove some common file name delimiters readline.set_completer_delims(' \t\n`@#%^&*()=+[{]}\\|;:\'",<>?') except ImportError: pass self.allow_kbdint = False self.nosigint = nosigint # Consider these characters as part of the command so when the users type # c.a or c['a'], it won't be recognized as a c(ontinue) command self.identchars = cmd.Cmd.identchars + '=.[](),"\'+-*/%@&|<>~^' # Read ~/.pdbrc and ./.pdbrc self.rcLines = [] if readrc: try: with open(os.path.expanduser('~/.pdbrc'), encoding='utf-8') as rcFile: self.rcLines.extend(rcFile) except OSError: pass try: with open(".pdbrc", encoding='utf-8') as rcFile: self.rcLines.extend(rcFile) except OSError: pass self.commands = {} # associates a command list to breakpoint numbers self.commands_doprompt = {} # for each bp num, tells if the prompt # must be disp. after execing the cmd list self.commands_silent = {} # for each bp num, tells if the stack trace # must be disp. after execing the cmd list self.commands_defining = False # True while in the process of defining # a command list self.commands_bnum = None # The breakpoint number for which we are # defining a list self._chained_exceptions = tuple() self._chained_exception_index = 0 def set_trace(self, frame=None): Pdb._last_pdb_instance = self if frame is None: frame = sys._getframe().f_back super().set_trace(frame) def sigint_handler(self, signum, frame): if self.allow_kbdint: raise KeyboardInterrupt self.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 = None self.stack = [] self.curindex = 0 if hasattr(self, 'curframe') and self.curframe: self.curframe.f_globals.pop('__pdb_convenience_variables', None) self.curframe = None self.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] = lineno tb = tb.tb_next self.curframe = self.stack[self.curindex][0] # The f_locals dictionary used to be updated from the actual frame # locals whenever the .f_locals accessor was called, so it was # cached here to ensure that modifications were not overwritten. While # the caching is no longer required now that f_locals is a direct proxy # on optimized frames, it's also harmless, so the code structure has # been left unchanged. self.curframe_locals = self.curframe.f_locals self.set_convenience_variable(self.curframe, '_frame', self.curframe) if self._chained_exceptions: self.set_convenience_variable( self.curframe, '_exception', self._chained_exceptions[self._chained_exception_index], ) if self.rcLines: self.cmdqueue = [ line for line in self.rcLines if line.strip() and not line.strip().startswith("#") ] self.rcLines = [] # Override Bdb methods def user_call(self, frame, argument_list): """This method is called when there is the remote possibility that we ever need to stop in this function.""" if self._wait_for_mainpyfile: return if 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): return self._wait_for_mainpyfile = False if self.bp_commands(frame): self.interaction(frame, None) user_opcode = user_line 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 hit if getattr(self, "currentbp", False) and \ self.currentbp in self.commands: currentbp = self.currentbp self.currentbp = 0 lastcmd_back = self.lastcmd self.setup(frame, None) for line in self.commands[currentbp]: self.onecmd(line) self.lastcmd = lastcmd_back if not self.commands_silent[currentbp]: self.print_stack_entry(self.stack[self.curindex]) if self.commands_doprompt[currentbp]: self._cmdloop() self.forget() return return 1 def user_return(self, frame, return_value): """This function is called when a return trap is set here.""" if self._wait_for_mainpyfile: return frame.f_locals['__return__'] = return_value self.set_convenience_variable(frame, '_retval', return_value) self.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: return exc_type, exc_value, exc_traceback = exc_info frame.f_locals['__exception__'] = exc_type, exc_value self.set_convenience_variable(frame, '_exception', 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_traceback and exc_type is StopIteration) else '' self.message('%s%s' % (prefix, self._format_exc(exc_value))) self.interaction(frame, exc_traceback) # General interaction function def _cmdloop(self): while True: try: # keyboard interrupts allow for an easy way to cancel # the current command, so allow them during interactive input self.allow_kbdint = True self.cmdloop() self.allow_kbdint = False break except KeyboardInterrupt: self.message('--KeyboardInterrupt--') def _validate_file_mtime(self): """Check if the source file of the current frame has been modified since the last time we saw it. If so, give a warning.""" try: filename = self.curframe.f_code.co_filename mtime = os.path.getmtime(filename) except Exception: return if (filename in self._file_mtime_table and mtime != self._file_mtime_table[filename]): self.message(f"*** WARNING: file '{filename}' was edited, " "running stale code until the program is rerun") self._file_mtime_table[filename] = mtime # Called before loop, handles display expressions # Set up convenience variable containers def _show_display(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 displayed if newvalue is not oldvalue and newvalue != oldvalue: displaying[expr] = newvalue self.message('display %s: %s [old: %s]' % (expr, self._safe_repr(newvalue, expr), self._safe_repr(oldvalue, expr))) def _get_tb_and_exceptions(self, tb_or_exc): """ Given a tracecack or an exception, return a tuple of chained exceptions and current traceback to inspect. This will deal with selecting the right ``__cause__`` or ``__context__`` as well as handling cycles, and return a flattened list of exceptions we can jump to with do_exceptions. """ _exceptions = [] if isinstance(tb_or_exc, BaseException): traceback, current = tb_or_exc.__traceback__, tb_or_exc while current is not None: if current in _exceptions: break _exceptions.append(current) if current.__cause__ is not None: current = current.__cause__ elif ( current.__context__ is not None and not current.__suppress_context__ ): current = current.__context__ if len(_exceptions) >= self.MAX_CHAINED_EXCEPTION_DEPTH: self.message( f"More than {self.MAX_CHAINED_EXCEPTION_DEPTH}" " chained exceptions found, not all exceptions" "will be browsable with `exceptions`." ) break else: traceback = tb_or_exc return tuple(reversed(_exceptions)), traceback @contextmanager def _hold_exceptions(self, exceptions): """ Context manager to ensure proper cleaning of exceptions references When given a chained exception instead of a traceback, pdb may hold references to many objects which may leak memory. We use this context manager to make sure everything is properly cleaned """ try: self._chained_exceptions = exceptions self._chained_exception_index = len(exceptions) - 1 yield finally: # we can't put those in forget as otherwise they would # be cleared on exception change self._chained_exceptions = tuple() self._chained_exception_index = 0 def interaction(self, frame, tb_or_exc): # Restore the previous signal handler at the Pdb prompt. if Pdb._previous_sigint_handler: try: signal.signal(signal.SIGINT, Pdb._previous_sigint_handler) except ValueError: # ValueError: signal only works in main thread pass else: Pdb._previous_sigint_handler = None _chained_exceptions, tb = self._get_tb_and_exceptions(tb_or_exc) if isinstance(tb_or_exc, BaseException): assert tb is not None, "main exception must have a traceback" with self._hold_exceptions(_chained_exceptions): self.setup(frame, tb) # We should print the stack entry if and only if the user input # is expected, and we should print it right before the user input. # We achieve this by appending _pdbcmd_print_frame_status to the # command queue. If cmdqueue is not exausted, the user input is # not expected and we will not print the stack entry. self.cmdqueue.append('_pdbcmd_print_frame_status') self._cmdloop() # If _pdbcmd_print_frame_status is not used, pop it out if self.cmdqueue and self.cmdqueue[-1] == '_pdbcmd_print_frame_status': self.cmdqueue.pop() self.forget() def displayhook(self, obj): """Custom displayhook for the exec in default(), which prevents assignment of the _ variable in the builtins. """ # reproduce the behavior of the standard displayhook, not printing None if obj is not None: self.message(repr(obj)) @contextmanager def _disable_command_completion(self): completenames = self.completenames try: self.completenames = self.completedefault yield finally: self.completenames = completenames return def _exec_in_closure(self, source, globals, locals): """ Run source code in closure so code object created within source can find variables in locals correctly returns True if the source is executed, False otherwise """ # Determine if the source should be executed in closure. Only when the # source compiled to multiple code objects, we should use this feature. # Otherwise, we can just raise an exception and normal exec will be used. code = compile(source, "", "exec") if not any(isinstance(const, CodeType) for const in code.co_consts): return False # locals could be a proxy which does not support pop # copy it first to avoid modifying the original locals locals_copy = dict(locals) locals_copy["__pdb_eval__"] = { "result": None, "write_back": {} } # If the source is an expression, we need to print its value try: compile(source, "", "eval") except SyntaxError: pass else: source = "__pdb_eval__['result'] = " + source # Add write-back to update the locals source = ("try:\n" + textwrap.indent(source, " ") + "\n" + "finally:\n" + " __pdb_eval__['write_back'] = locals()") # Build a closure source code with freevars from locals like: # def __pdb_outer(): # var = None # def __pdb_scope(): # This is the code object we want to execute # nonlocal var # # return __pdb_scope.__code__ source_with_closure = ("def __pdb_outer():\n" + "\n".join(f" {var} = None" for var in locals_copy) + "\n" + " def __pdb_scope():\n" + "\n".join(f" nonlocal {var}" for var in locals_copy) + "\n" + textwrap.indent(source, " ") + "\n" + " return __pdb_scope.__code__" ) # Get the code object of __pdb_scope() # The exec fills locals_copy with the __pdb_outer() function and we can call # that to get the code object of __pdb_scope() ns = {} try: exec(source_with_closure, {}, ns) except Exception: return False code = ns["__pdb_outer"]() cells = tuple(types.CellType(locals_copy.get(var)) for var in code.co_freevars) try: exec(code, globals, locals_copy, closure=cells) except Exception: return False # get the data we need from the statement pdb_eval = locals_copy["__pdb_eval__"] # __pdb_eval__ should not be updated back to locals pdb_eval["write_back"].pop("__pdb_eval__") # Write all local variables back to locals locals.update(pdb_eval["write_back"]) eval_result = pdb_eval["result"] if eval_result is not None: print(repr(eval_result)) return True def default(self, line): if line[:1] == '!': line = line[1:].strip() locals = self.curframe_locals globals = self.curframe.f_globals try: buffer = line if (code := codeop.compile_command(line + '\n', '', 'single')) is None: # Multi-line mode with self._disable_command_completion(): buffer = line continue_prompt = "... " while (code := codeop.compile_command(buffer, '', 'single')) is None: if self.use_rawinput: try: line = input(continue_prompt) except (EOFError, KeyboardInterrupt): self.lastcmd = "" print('\n') return else: self.stdout.write(continue_prompt) self.stdout.flush() line = self.stdin.readline() if not len(line): self.lastcmd = "" self.stdout.write('\n') self.stdout.flush() return else: line = line.rstrip('\r\n') buffer += '\n' + line save_stdout = sys.stdout save_stdin = sys.stdin save_displayhook = sys.displayhook try: sys.stdin = self.stdin sys.stdout = self.stdout sys.displayhook = self.displayhook if not self._exec_in_closure(buffer, globals, locals): exec(code, globals, locals) finally: sys.stdout = save_stdout sys.stdin = save_stdin sys.displayhook = save_displayhook except: self._error_exc() def _replace_convenience_variables(self, line): """Replace the convenience variables in 'line' with their values. e.g. $foo is replaced by __pdb_convenience_variables["foo"]. Note: such pattern in string literals will be skipped""" if "$" not in line: return line dollar_start = dollar_end = -1 replace_variables = [] try: for t in tokenize.generate_tokens(io.StringIO(line).readline): token_type, token_string, start, end, _ = t if token_type == token.OP and token_string == '$': dollar_start, dollar_end = start, end elif start == dollar_end and token_type == token.NAME: # line is a one-line command so we only care about column replace_variables.append((dollar_start[1], end[1], token_string)) except tokenize.TokenError: return line if not replace_variables: return line last_end = 0 line_pieces = [] for start, end, name in replace_variables: line_pieces.append(line[last_end:start] + f'__pdb_convenience_variables["{name}"]') last_end = end line_pieces.append(line[last_end:]) return ''.join(line_pieces) def precmd(self, line): """Handle alias expansion and ';;' separator.""" if not line.strip(): return line args = line.split() while args[0] in self.aliases: line = self.aliases[args[0]] for idx in range(1, 10): if f'%{idx}' in line: if idx >= len(args): self.error(f"Not enough arguments for alias '{args[0]}'") # This is a no-op return "!" line = line.replace(f'%{idx}', args[idx]) elif '%*' not in line: if idx < len(args): self.error(f"Too many arguments for alias '{args[0]}'") # This is a no-op return "!" break line = line.replace("%*", ' '.join(args[1:])) args = line.split() # split into ';;' separated commands # unless it's an alias command if args[0] != 'alias': marker = line.find(';;') if marker >= 0: # queue up everything after marker next = line[marker+2:].lstrip() self.cmdqueue.insert(0, next) line = line[:marker].rstrip() # Replace all the convenience variables line = self._replace_convenience_variables(line) return line def onecmd(self, line): """Interpret the argument as though it had been typed in response to the prompt. Checks whether this line is typed at the normal prompt or in a breakpoint command list definition. """ if not self.commands_defining: self._validate_file_mtime() if line.startswith('_pdbcmd'): command, arg, line = self.parseline(line) if hasattr(self, command): return getattr(self, command)(arg) 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: return False if cmd == 'silent': self.commands_silent[self.commands_bnum] = True return False # continue to handle other cmd def in the cmd list elif cmd == 'end': return True # end of cmd list elif cmd == 'EOF': print('') return True # end of cmd list cmdlist = self.commands[self.commands_bnum] if arg: cmdlist.append(cmd+' '+arg) else: cmdlist.append(cmd) # Determine if we must stop try: func = getattr(self, 'do_' + cmd) except AttributeError: func = self.default # one of the resuming commands if func.__name__ in self.commands_resuming: self.commands_doprompt[self.commands_bnum] = False return True return False # interface abstraction functions def message(self, msg, end='\n'): print(msg, end=end, file=self.stdout) def error(self, msg): print('***', msg, file=self.stdout) # convenience variables def set_convenience_variable(self, frame, name, value): if '__pdb_convenience_variables' not in frame.f_globals: frame.f_globals['__pdb_convenience_variables'] = {} frame.f_globals['__pdb_convenience_variables'][name] = value # Generic completion functions. Individual complete_foo methods can be # assigned below to one of these functions. def completenames(self, text, line, begidx, endidx): # Overwrite completenames() of cmd so for the command completion, # if no current command matches, check for expressions as well commands = super().completenames(text, line, begidx, endidx) for alias in self.aliases: if alias.startswith(text): commands.append(alias) if commands: return commands else: expressions = self._complete_expression(text, line, begidx, endidx) if expressions: return expressions return self.completedefault(text, line, begidx, endidx) 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(glob.escape(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 ret def _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, **self.curframe_locals} if text.startswith("$"): # Complete convenience variables conv_vars = self.curframe.f_globals.get('__pdb_convenience_variables', {}) return [f"${name}" for name in conv_vars if name.startswith(text[1:])] if '.' in text: # Walk an attribute chain up to the last part, similar to what # rlcompleter does. This will bail if any of the parts are not # simple attribute access, which is what we want. dotted = text.split('.') try: obj = ns[dotted[0]] for part in dotted[1:-1]: obj = getattr(obj, part) except (KeyError, AttributeError): return [] prefix = '.'.join(dotted[:-1]) + '.' return [prefix + n for n in dir(obj) if n.startswith(dotted[-1])] else: # Complete a simple name. return [n for n in ns.keys() if n.startswith(text)] def completedefault(self, text, line, begidx, endidx): if text.startswith("$"): # Complete convenience variables conv_vars = self.curframe.f_globals.get('__pdb_convenience_variables', {}) return [f"${name}" for name in conv_vars if name.startswith(text[1:])] # Use rlcompleter to do the completion state = 0 matches = [] completer = Completer(self.curframe.f_globals | self.curframe_locals) while (match := completer.complete(text, state)) is not None: matches.append(match) state += 1 return matches # Pdb meta commands, only intended to be used internally by pdb def _pdbcmd_print_frame_status(self, arg): self.print_stack_trace(0) self._show_display() # Command definitions, called by cmdloop() # The argument is the remaining string on the command line # Return true to exit from the command loop def do_commands(self, arg): """(Pdb) 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 and follow it immediately with end; that is, give no commands. With no bpnumber argument, commands refers to the last breakpoint set. You can use breakpoint commands to start your program up again. Simply use the continue command, or step, or any other command 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 was immediately followed by end). This is because any time you resume execution (even with a simple next or step), you may encounter another breakpoint -- which could have its own command list, leading to ambiguities about which list to execute. If you use the 'silent' command in the command list, the usual message about stopping at a breakpoint is not printed. This may be desirable for breakpoints that are to print a specific message and then continue. If none of the other commands print anything, you will see no sign that the breakpoint was reached. """ if not arg: bnum = len(bdb.Breakpoint.bpbynumber) - 1 else: try: bnum = int(arg) except: self._print_invalid_arg(arg) return try: self.get_bpbynumber(bnum) except ValueError as err: self.error('cannot set commands: %s' % err) return self.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 = None self.commands[bnum] = [] self.commands_doprompt[bnum] = True self.commands_silent[bnum] = False prompt_back = self.prompt self.prompt = '(com) ' self.commands_defining = True try: 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 = False self.prompt = prompt_back complete_commands = _complete_bpnumber def 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 the current file. With a function name, set a break at the first executable line of that function. If a second argument is present, it is a string specifying an expression which must evaluate 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 that hasn't been loaded yet). The file is searched for on sys.path; the .py suffix may be omitted. """ if not arg: if self.breaks: # There's at least one self.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 filename filename = None lineno = None cond = None comma = arg.find(',') if comma > 0: # parse stuff after comma: "condition" cond = arg[comma+1:].lstrip() if err := self._compile_error_message(cond): self.error('Invalid condition %s: %r' % (cond, err)) return arg = arg[:comma].rstrip() # parse stuff before comma: [filename:]lineno | function colon = arg.rfind(':') funcname = None if colon >= 0: filename = arg[:colon].rstrip() f = self.lookupmodule(filename) if not f: self.error('%r not found from sys.path' % filename) return else: filename = f arg = arg[colon+1:].lstrip() try: lineno = int(arg) except ValueError: self.error('Bad lineno: %s' % arg) return else: # no colon; can be lineno or function try: lineno = int(arg) except ValueError: try: func = eval(arg, self.curframe.f_globals, self.curframe_locals) except: func = arg try: 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_name lineno = find_first_executable_line(code) filename = code.co_filename except: # 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) return funcname = ok # ok contains a function name lineno = int(ln) if not filename: filename = self.defaultFile() # Check for reasonable breakpoint line = self.checkline(filename, lineno) if line: # now set the break point err = 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 debuggers def defaultFile(self): """Produce a reasonable default.""" filename = self.curframe.f_code.co_filename if filename == '' and self.mainpyfile: filename = self.mainpyfile return filename do_b = do_break complete_break = _complete_location complete_b = _complete_location def do_tbreak(self, arg): """tbreak [ ([filename:]lineno | function) [, condition] ] Same arguments as break, but sets a temporary breakpoint: it is automatically deleted when first hit. """ self.do_break(arg, 1) complete_tbreak = _complete_location def lineinfo(self, identifier): failed = (None, None, None) # Input is identifier, may be in single quotes idstring = identifier.split("'") if len(idstring) == 1: # not in single quotes id = idstring[0].strip() elif len(idstring) == 3: # quoted id = idstring[1].strip() else: return failed if id == '': return failed parts = id.split('.') # Protection for derived debuggers if parts[0] == 'self': del parts[0] if len(parts) == 0: return failed # Best first guess at file to look at fname = self.defaultFile() if len(parts) == 1: item = parts[0] else: # More than one part. # First is module, second is method/class f = self.lookupmodule(parts[0]) if f: fname = f item = parts[1] answer = find_function(item, self.canonic(fname)) return answer or failed def 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, blank line 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 frame frame = getattr(self, 'curframe', None) globs = frame.f_globals if frame else None line = linecache.getline(filename, lineno, globs) if not line: self.message('End of file') return 0 line = line.strip() # Don't allow setting breakpoint at a blank line if (not line or (line[0] == '#') or (line[:3] == '"""') or line[:3] == "'''"): self.error('Blank or comment') return 0 return lineno def do_enable(self, arg): """enable bpnumber [bpnumber ...] Enables the breakpoints given as a space separated list of breakpoint 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_bpnumber def do_disable(self, arg): """disable bpnumber [bpnumber ...] Disables the breakpoints given as a space separated list of breakpoint numbers. Disabling a breakpoint means it cannot cause the program to stop execution, but unlike clearing a breakpoint, 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_bpnumber def do_condition(self, arg): """condition bpnumber [condition] Set a new condition for the breakpoint, an expression which must evaluate to true before the breakpoint is honored. If condition is absent, any existing condition is removed; i.e., the breakpoint is made unconditional. """ args = arg.split(' ', 1) try: cond = args[1] if err := self._compile_error_message(cond): self.error('Invalid condition %s: %r' % (cond, err)) return except IndexError: cond = None try: bp = self.get_bpbynumber(args[0].strip()) except IndexError: self.error('Breakpoint number expected') except ValueError as err: self.error(err) else: bp.cond = cond if 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_bpnumber def do_ignore(self, arg): """ignore bpnumber [count] Set the ignore count for the given breakpoint number. If count is omitted, the ignore count is set to 0. A breakpoint becomes active when the ignore count is zero. When non-zero, the count is decremented each time the breakpoint is reached and the breakpoint is not disabled and any associated condition evaluates to true. """ args = arg.split() if not args: self.error('Breakpoint number expected') return if len(args) == 1: count = 0 elif len(args) == 2: try: count = int(args[1]) except ValueError: self._print_invalid_arg(arg) return else: self._print_invalid_arg(arg) return try: bp = self.get_bpbynumber(args[0].strip()) except ValueError as err: self.error(err) else: bp.ignore = count if count > 0: if count > 1: countstr = '%d crossings' % count else: 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_bpnumber def do_clear(self, arg): """cl(ear) [filename:lineno | bpnumber ...] With a space separated list of breakpoint numbers, clear those breakpoints. Without argument, clear all breaks (but first 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) return if ':' 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)" % arg else: 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) return numberlist = 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_location complete_cl = _complete_location def do_where(self, arg): """w(here) [count] Print a stack trace. If count is not specified, print the full stack. If count is 0, print the current frame entry. If count is positive, print count entries from the most recent frame. If count is negative, print -count entries from the least recent frame. An arrow indicates the "current frame", which determines the context of most commands. 'bt' is an alias for this command. """ if not arg: count = None else: try: count = int(arg) except ValueError: self.error('Invalid count (%s)' % arg) return self.print_stack_trace(count) do_w = do_where do_bt = do_where def _select_frame(self, number): assert 0 <= number < len(self.stack) self.curindex = number self.curframe = self.stack[self.curindex][0] self.curframe_locals = self.curframe.f_locals self.set_convenience_variable(self.curframe, '_frame', self.curframe) self.print_stack_entry(self.stack[self.curindex]) self.lineno = None def do_exceptions(self, arg): """exceptions [number] List or change current exception in an exception chain. Without arguments, list all the current exception in the exception chain. Exceptions will be numbered, with the current exception indicated with an arrow. If given an integer as argument, switch to the exception at that index. """ if not self._chained_exceptions: self.message( "Did not find chained exceptions. To move between" " exceptions, pdb/post_mortem must be given an exception" " object rather than a traceback." ) return if not arg: for ix, exc in enumerate(self._chained_exceptions): prompt = ">" if ix == self._chained_exception_index else " " rep = repr(exc) if len(rep) > 80: rep = rep[:77] + "..." indicator = ( " -" if self._chained_exceptions[ix].__traceback__ is None else f"{ix:>3}" ) self.message(f"{prompt} {indicator} {rep}") else: try: number = int(arg) except ValueError: self.error("Argument must be an integer") return if 0 <= number < len(self._chained_exceptions): if self._chained_exceptions[number].__traceback__ is None: self.error("This exception does not have a traceback, cannot jump to it") return self._chained_exception_index = number self.setup(None, self._chained_exceptions[number].__traceback__) self.print_stack_entry(self.stack[self.curindex]) else: self.error("No exception with that number") def do_up(self, arg): """u(p) [count] Move the current frame count (default one) levels up in the stack trace (to an older frame). """ if self.curindex == 0: self.error('Oldest frame') return try: count = int(arg or 1) except ValueError: self.error('Invalid frame count (%s)' % arg) return if count < 0: newframe = 0 else: newframe = max(0, self.curindex - count) self._select_frame(newframe) do_u = do_up def do_down(self, arg): """d(own) [count] Move the current frame count (default one) levels down in the stack trace (to a newer frame). """ if self.curindex + 1 == len(self.stack): self.error('Newest frame') return try: count = int(arg or 1) except ValueError: self.error('Invalid frame count (%s)' % arg) return if count < 0: newframe = len(self.stack) - 1 else: newframe = min(len(self.stack) - 1, self.curindex + count) self._select_frame(newframe) do_d = do_down def do_until(self, arg): """unt(il) [lineno] Without argument, continue execution until the line with a number greater than the current one is reached. With a line number, continue execution until a line with a number greater or equal to that is reached. In both cases, also stop when the current frame returns. """ if arg: try: lineno = int(arg) except ValueError: self.error('Error in argument: %r' % arg) return if lineno <= self.curframe.f_lineno: self.error('"until" line number is smaller than current ' 'line number') return else: lineno = None self.set_until(self.curframe, lineno) return 1 do_unt = do_until def 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 current function). """ if arg: self._print_invalid_arg(arg) return self.set_step() return 1 do_s = do_step def do_next(self, arg): """n(ext) Continue execution until the next line in the current function is reached or it returns. """ if arg: self._print_invalid_arg(arg) return self.set_next(self.curframe) return 1 do_n = do_next def do_run(self, arg): """run [args...] Restart the debugged python program. If a string is supplied it is split with "shlex", and the result is used as the new sys.argv. History, breakpoints, actions and debugger options are preserved. "restart" is an alias for "run". """ if arg: import shlex argv0 = sys.argv[0:1] try: sys.argv = shlex.split(arg) except ValueError as e: self.error('Cannot run %s: %s' % (arg, e)) return sys.argv[:0] = argv0 # this is caught in the main debugger loop raise Restart do_restart = do_run def do_return(self, arg): """r(eturn) Continue execution until the current function returns. """ if arg: self._print_invalid_arg(arg) return self.set_return(self.curframe) return 1 do_r = do_return def do_continue(self, arg): """c(ont(inue)) Continue execution, only stop when a breakpoint is encountered. """ if arg: self._print_invalid_arg(arg) return 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? pass self.set_continue() return 1 do_c = do_cont = do_continue def do_jump(self, arg): """j(ump) lineno Set the next line that will be executed. Only available in the bottom-most frame. This lets you jump back and execute code again, or jump forward to skip code that you don't want to run. It should be noted that not all jumps are allowed -- for instance it is not possible to jump into the middle of a for loop or out of a finally clause. """ if self.curindex + 1 != len(self.stack): self.error('You can only jump within the bottom frame') return try: 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 position self.curframe.f_lineno = arg self.stack[self.curindex] = self.stack[self.curindex][0], arg self.print_stack_entry(self.stack[self.curindex]) except ValueError as e: self.error('Jump failed: %s' % e) do_j = do_jump def do_debug(self, arg): """debug code Enter a recursive debugger that steps through the code argument (which is an arbitrary expression or statement to be executed in the current environment). """ sys.settrace(None) globals = self.curframe.f_globals locals = self.curframe_locals p = 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: self._error_exc() self.message("LEAVING RECURSIVE DEBUGGER") sys.settrace(self.trace_dispatch) self.lastcmd = p.lastcmd complete_debug = _complete_expression def do_quit(self, arg): """q(uit) | exit Quit from the debugger. The program being executed is aborted. """ self._user_requested_quit = True self.set_quit() return 1 do_q = do_quit do_exit = do_quit def do_EOF(self, arg): """EOF Handles the receipt of EOF as a command. """ self.message('') self._user_requested_quit = True self.set_quit() return 1 def do_args(self, arg): """a(rgs) Print the argument list of the current function. """ if arg: self._print_invalid_arg(arg) return co = self.curframe.f_code dict = self.curframe_locals n = co.co_argcount + co.co_kwonlyargcount if co.co_flags & inspect.CO_VARARGS: n = n+1 if co.co_flags & inspect.CO_VARKEYWORDS: n = n+1 for i in range(n): name = co.co_varnames[i] if name in dict: self.message('%s = %s' % (name, self._safe_repr(dict[name], name))) else: self.message('%s = *** undefined ***' % (name,)) do_a = do_args def do_retval(self, arg): """retval Print the return value for the last return of a function. """ if arg: self._print_invalid_arg(arg) return if '__return__' in self.curframe_locals: self.message(self._safe_repr(self.curframe_locals['__return__'], "retval")) else: self.error('Not yet returned!') do_rv = do_retval def _getval(self, arg): try: return eval(arg, self.curframe.f_globals, self.curframe_locals) except: self._error_exc() raise def _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 BaseException as exc: return _rstr('** raised %s **' % self._format_exc(exc)) def _error_exc(self): exc = sys.exception() self.error(self._format_exc(exc)) def _msg_val_func(self, arg, func): try: val = self._getval(arg) except: return # _getval() has displayed the error try: self.message(func(val)) except: self._error_exc() def _safe_repr(self, obj, expr): try: return repr(obj) except Exception as e: return _rstr(f"*** repr({expr}) failed: {self._format_exc(e)} ***") def do_p(self, arg): """p expression Print the value of the expression. """ self._msg_val_func(arg, repr) def do_pp(self, arg): """pp expression Pretty-print the value of the expression. """ self._msg_val_func(arg, pprint.pformat) complete_print = _complete_expression complete_p = _complete_expression complete_pp = _complete_expression def 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 previous listing. With . as argument, list 11 lines around the current line. With one argument, list 11 lines starting at that line. With two arguments, list the given range; if the second argument 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 the exception was originally raised or propagated is indicated by ">>", if it differs from the current line. """ self.lastcmd = 'list' last = None if 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 count last = first + last else: first = int(arg.strip()) first = max(1, first - 5) except ValueError: self.error('Error in argument: %r' % arg) return elif self.lineno is None or arg == '.': first = max(1, self.curframe.f_lineno - 5) else: first = self.lineno + 1 if last is None: last = first + 10 filename = self.curframe.f_code.co_filename # gh-93696: stdlib frozen modules provide a useful __file__ # this workaround can be removed with the closure of gh-89815 if filename.startswith("