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Editing: debugging.py
"""Interactive debugging with PDB, the Python Debugger.""" import argparse import functools import sys import types import unittest from typing import Any from typing import Callable from typing import Generator from typing import List from typing import Optional from typing import Tuple from typing import Type from typing import TYPE_CHECKING from typing import Union from _pytest import outcomes from _pytest._code import ExceptionInfo from _pytest.config import Config from _pytest.config import ConftestImportFailure from _pytest.config import hookimpl from _pytest.config import PytestPluginManager from _pytest.config.argparsing import Parser from _pytest.config.exceptions import UsageError from _pytest.nodes import Node from _pytest.reports import BaseReport if TYPE_CHECKING: from _pytest.capture import CaptureManager from _pytest.runner import CallInfo def _validate_usepdb_cls(value: str) -> Tuple[str, str]: """Validate syntax of --pdbcls option.""" try: modname, classname = value.split(":") except ValueError as e: raise argparse.ArgumentTypeError( f"{value!r} is not in the format 'modname:classname'" ) from e return (modname, classname) def pytest_addoption(parser: Parser) -> None: group = parser.getgroup("general") group._addoption( "--pdb", dest="usepdb", action="store_true", help="Start the interactive Python debugger on errors or KeyboardInterrupt", ) group._addoption( "--pdbcls", dest="usepdb_cls", metavar="modulename:classname", type=_validate_usepdb_cls, help="Specify a custom interactive Python debugger for use with --pdb." "For example: --pdbcls=IPython.terminal.debugger:TerminalPdb", ) group._addoption( "--trace", dest="trace", action="store_true", help="Immediately break when running each test", ) def pytest_configure(config: Config) -> None: import pdb if config.getvalue("trace"): config.pluginmanager.register(PdbTrace(), "pdbtrace") if config.getvalue("usepdb"): config.pluginmanager.register(PdbInvoke(), "pdbinvoke") pytestPDB._saved.append( (pdb.set_trace, pytestPDB._pluginmanager, pytestPDB._config) ) pdb.set_trace = pytestPDB.set_trace pytestPDB._pluginmanager = config.pluginmanager pytestPDB._config = config # NOTE: not using pytest_unconfigure, since it might get called although # pytest_configure was not (if another plugin raises UsageError). def fin() -> None: ( pdb.set_trace, pytestPDB._pluginmanager, pytestPDB._config, ) = pytestPDB._saved.pop() config.add_cleanup(fin) class pytestPDB: """Pseudo PDB that defers to the real pdb.""" _pluginmanager: Optional[PytestPluginManager] = None _config: Optional[Config] = None _saved: List[ Tuple[Callable[..., None], Optional[PytestPluginManager], Optional[Config]] ] = [] _recursive_debug = 0 _wrapped_pdb_cls: Optional[Tuple[Type[Any], Type[Any]]] = None @classmethod def _is_capturing(cls, capman: Optional["CaptureManager"]) -> Union[str, bool]: if capman: return capman.is_capturing() return False @classmethod def _import_pdb_cls(cls, capman: Optional["CaptureManager"]): if not cls._config: import pdb # Happens when using pytest.set_trace outside of a test. return pdb.Pdb usepdb_cls = cls._config.getvalue("usepdb_cls") if cls._wrapped_pdb_cls and cls._wrapped_pdb_cls[0] == usepdb_cls: return cls._wrapped_pdb_cls[1] if usepdb_cls: modname, classname = usepdb_cls try: __import__(modname) mod = sys.modules[modname] # Handle --pdbcls=pdb:pdb.Pdb (useful e.g. with pdbpp). parts = classname.split(".") pdb_cls = getattr(mod, parts[0]) for part in parts[1:]: pdb_cls = getattr(pdb_cls, part) except Exception as exc: value = ":".join((modname, classname)) raise UsageError( f"--pdbcls: could not import {value!r}: {exc}" ) from exc else: import pdb pdb_cls = pdb.Pdb wrapped_cls = cls._get_pdb_wrapper_class(pdb_cls, capman) cls._wrapped_pdb_cls = (usepdb_cls, wrapped_cls) return wrapped_cls @classmethod def _get_pdb_wrapper_class(cls, pdb_cls, capman: Optional["CaptureManager"]): import _pytest.config # Type ignored because mypy doesn't support "dynamic" # inheritance like this. class PytestPdbWrapper(pdb_cls): # type: ignore[valid-type,misc] _pytest_capman = capman _continued = False def do_debug(self, arg): cls._recursive_debug += 1 ret = super().do_debug(arg) cls._recursive_debug -= 1 return ret def do_continue(self, arg): ret = super().do_continue(arg) if cls._recursive_debug == 0: assert cls._config is not None tw = _pytest.config.create_terminal_writer(cls._config) tw.line() capman = self._pytest_capman capturing = pytestPDB._is_capturing(capman) if capturing: if capturing == "global": tw.sep(">", "PDB continue (IO-capturing resumed)") else: tw.sep( ">", "PDB continue (IO-capturing resumed for %s)" % capturing, ) assert capman is not None capman.resume() else: tw.sep(">", "PDB continue") assert cls._pluginmanager is not None cls._pluginmanager.hook.pytest_leave_pdb(config=cls._config, pdb=self) self._continued = True return ret do_c = do_cont = do_continue def do_quit(self, arg): """Raise Exit outcome when quit command is used in pdb. This is a bit of a hack - it would be better if BdbQuit could be handled, but this would require to wrap the whole pytest run, and adjust the report etc. """ ret = super().do_quit(arg) if cls._recursive_debug == 0: outcomes.exit("Quitting debugger") return ret do_q = do_quit do_exit = do_quit def setup(self, f, tb): """Suspend on setup(). Needed after do_continue resumed, and entering another breakpoint again. """ ret = super().setup(f, tb) if not ret and self._continued: # pdb.setup() returns True if the command wants to exit # from the interaction: do not suspend capturing then. if self._pytest_capman: self._pytest_capman.suspend_global_capture(in_=True) return ret def get_stack(self, f, t): stack, i = super().get_stack(f, t) if f is None: # Find last non-hidden frame. i = max(0, len(stack) - 1) while i and stack[i][0].f_locals.get("__tracebackhide__", False): i -= 1 return stack, i return PytestPdbWrapper @classmethod def _init_pdb(cls, method, *args, **kwargs): """Initialize PDB debugging, dropping any IO capturing.""" import _pytest.config if cls._pluginmanager is None: capman: Optional[CaptureManager] = None else: capman = cls._pluginmanager.getplugin("capturemanager") if capman: capman.suspend(in_=True) if cls._config: tw = _pytest.config.create_terminal_writer(cls._config) tw.line() if cls._recursive_debug == 0: # Handle header similar to pdb.set_trace in py37+. header = kwargs.pop("header", None) if header is not None: tw.sep(">", header) else: capturing = cls._is_capturing(capman) if capturing == "global": tw.sep(">", f"PDB {method} (IO-capturing turned off)") elif capturing: tw.sep( ">", "PDB %s (IO-capturing turned off for %s)" % (method, capturing), ) else: tw.sep(">", f"PDB {method}") _pdb = cls._import_pdb_cls(capman)(**kwargs) if cls._pluginmanager: cls._pluginmanager.hook.pytest_enter_pdb(config=cls._config, pdb=_pdb) return _pdb @classmethod def set_trace(cls, *args, **kwargs) -> None: """Invoke debugging via ``Pdb.set_trace``, dropping any IO capturing.""" frame = sys._getframe().f_back _pdb = cls._init_pdb("set_trace", *args, **kwargs) _pdb.set_trace(frame) class PdbInvoke: def pytest_exception_interact( self, node: Node, call: "CallInfo[Any]", report: BaseReport ) -> None: capman = node.config.pluginmanager.getplugin("capturemanager") if capman: capman.suspend_global_capture(in_=True) out, err = capman.read_global_capture() sys.stdout.write(out) sys.stdout.write(err) assert call.excinfo is not None if not isinstance(call.excinfo.value, unittest.SkipTest): _enter_pdb(node, call.excinfo, report) def pytest_internalerror(self, excinfo: ExceptionInfo[BaseException]) -> None: tb = _postmortem_traceback(excinfo) post_mortem(tb) class PdbTrace: @hookimpl(hookwrapper=True) def pytest_pyfunc_call(self, pyfuncitem) -> Generator[None, None, None]: wrap_pytest_function_for_tracing(pyfuncitem) yield def wrap_pytest_function_for_tracing(pyfuncitem): """Change the Python function object of the given Function item by a wrapper which actually enters pdb before calling the python function itself, effectively leaving the user in the pdb prompt in the first statement of the function.""" _pdb = pytestPDB._init_pdb("runcall") testfunction = pyfuncitem.obj # we can't just return `partial(pdb.runcall, testfunction)` because (on # python < 3.7.4) runcall's first param is `func`, which means we'd get # an exception if one of the kwargs to testfunction was called `func`. @functools.wraps(testfunction) def wrapper(*args, **kwargs): func = functools.partial(testfunction, *args, **kwargs) _pdb.runcall(func) pyfuncitem.obj = wrapper def maybe_wrap_pytest_function_for_tracing(pyfuncitem): """Wrap the given pytestfunct item for tracing support if --trace was given in the command line.""" if pyfuncitem.config.getvalue("trace"): wrap_pytest_function_for_tracing(pyfuncitem) def _enter_pdb( node: Node, excinfo: ExceptionInfo[BaseException], rep: BaseReport ) -> BaseReport: # XXX we re-use the TerminalReporter's terminalwriter # because this seems to avoid some encoding related troubles # for not completely clear reasons. tw = node.config.pluginmanager.getplugin("terminalreporter")._tw tw.line() showcapture = node.config.option.showcapture for sectionname, content in ( ("stdout", rep.capstdout), ("stderr", rep.capstderr), ("log", rep.caplog), ): if showcapture in (sectionname, "all") and content: tw.sep(">", "captured " + sectionname) if content[-1:] == "\n": content = content[:-1] tw.line(content) tw.sep(">", "traceback") rep.toterminal(tw) tw.sep(">", "entering PDB") tb = _postmortem_traceback(excinfo) rep._pdbshown = True # type: ignore[attr-defined] post_mortem(tb) return rep def _postmortem_traceback(excinfo: ExceptionInfo[BaseException]) -> types.TracebackType: from doctest import UnexpectedException if isinstance(excinfo.value, UnexpectedException): # A doctest.UnexpectedException is not useful for post_mortem. # Use the underlying exception instead: return excinfo.value.exc_info[2] elif isinstance(excinfo.value, ConftestImportFailure): # A config.ConftestImportFailure is not useful for post_mortem. # Use the underlying exception instead: return excinfo.value.excinfo[2] else: assert excinfo._excinfo is not None return excinfo._excinfo[2] def post_mortem(t: types.TracebackType) -> None: p = pytestPDB._init_pdb("post_mortem") p.reset() p.interaction(None, t) if p.quitting: outcomes.exit("Quitting debugger")
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