Python warnings.showwarning() Examples

def idle_showwarning(
        message, category, filename, lineno, file=None, line=None):
    """Show Idle-format warning (after replacing warnings.showwarning).

    The differences are the formatter called, the file=None replacement,
    which can be None, the capture of the consequence AttributeError,
    and the output of a hard-coded prompt.
    """
    if file is None:
        file = warning_stream
    try:
        file.write(idle_formatwarning(
                message, category, filename, lineno, line=line))
        file.write(">>> ")
    except (AttributeError, IOError):
        pass  # if file (probably __stderr__) is invalid, skip warning. 

def _showwarning(message, category, filename, lineno, file=None, line=None):
    """
    Implementation of showwarnings which redirects to logging, which will first
    check to see if the file parameter is None. If a file is specified, it will
    delegate to the original warnings implementation of showwarning. Otherwise,
    it will call warnings.formatwarning and will log the resulting string to a
    warnings logger named "py.warnings" with level logging.WARNING.
    """
    if file is not None:
        if _warnings_showwarning is not None:
            _warnings_showwarning(message, category, filename, lineno, file, line)
    else:
        s = warnings.formatwarning(message, category, filename, lineno, line)
        logger = getLogger("py.warnings")
        if not logger.handlers:
            logger.addHandler(NullHandler())
        logger.warning("%s", s) 

def _showwarning(message, category, filename, lineno, file=None, line=None):
    """
    Implementation of showwarnings which redirects to logging, which will first
    check to see if the file parameter is None. If a file is specified, it will
    delegate to the original warnings implementation of showwarning. Otherwise,
    it will call warnings.formatwarning and will log the resulting string to a
    warnings logger named "py.warnings" with level logging.WARNING.
    """
    if file is not None:
        if _warnings_showwarning is not None:
            _warnings_showwarning(message, category, filename, lineno, file, line)
    else:
        s = warnings.formatwarning(message, category, filename, lineno, line)
        logger = getLogger("py.warnings")
        if not logger.handlers:
            logger.addHandler(NullHandler())
        logger.warning("%s", s) 

def _showwarning(message, category, filename, lineno, file=None, line=None):
    """
    Implementation of showwarnings which redirects to logging, which will first
    check to see if the file parameter is None. If a file is specified, it will
    delegate to the original warnings implementation of showwarning. Otherwise,
    it will call warnings.formatwarning and will log the resulting string to a
    warnings logger named "py.warnings" with level logging.WARNING.
    """
    if file is not None:
        if _warnings_showwarning is not None:
            _warnings_showwarning(message, category, filename, lineno, file, line)
    else:
        s = warnings.formatwarning(message, category, filename, lineno, line)
        logger = getLogger("py.warnings")
        if not logger.handlers:
            logger.addHandler(NullHandler())
        logger.warning("%s", s) 

def __enter__(self):
        if self._entered:
            raise RuntimeError("Cannot enter %r twice" % self)
        self._entered = True
        self._filters = self._module.filters
        self._module.filters = self._filters[:]
        self._showwarning = self._module.showwarning
        if self._record:
            log = []

            def showwarning(*args, **kwargs):
                log.append(WarningMessage(*args, **kwargs))
            self._module.showwarning = showwarning
            return log
        else:
            return None 

def _showwarning(message, category, filename, lineno, file=None, line=None):
    """
    Implementation of showwarnings which redirects to logging, which will first
    check to see if the file parameter is None. If a file is specified, it will
    delegate to the original warnings implementation of showwarning. Otherwise,
    it will call warnings.formatwarning and will log the resulting string to a
    warnings logger named "py.warnings" with level logging.WARNING.
    """
    if file is not None:
        if _warnings_showwarning is not None:
            _warnings_showwarning(message, category, filename, lineno, file, line)
    else:
        s = warnings.formatwarning(message, category, filename, lineno, line)
        logger = getLogger("py.warnings")
        if not logger.handlers:
            logger.addHandler(NullHandler())
        logger.warning("%s", s) 

def test_warnings(self):
        with warnings.catch_warnings():
            logging.captureWarnings(True)
            try:
                warnings.filterwarnings("always", category=UserWarning)
                file = cStringIO.StringIO()
                h = logging.StreamHandler(file)
                logger = logging.getLogger("py.warnings")
                logger.addHandler(h)
                warnings.warn("I'm warning you...")
                logger.removeHandler(h)
                s = file.getvalue()
                h.close()
                self.assertTrue(s.find("UserWarning: I'm warning you...\n") > 0)

                #See if an explicit file uses the original implementation
                file = cStringIO.StringIO()
                warnings.showwarning("Explicit", UserWarning, "dummy.py", 42,
                                        file, "Dummy line")
                s = file.getvalue()
                file.close()
                self.assertEqual(s,
                        "dummy.py:42: UserWarning: Explicit\n  Dummy line\n")
            finally:
                logging.captureWarnings(False) 

def __enter__(self):
        if self._entered:
            raise RuntimeError("Cannot enter %r twice" % self)
        self._entered = True
        self._filters = self._module.filters
        self._module.filters = self._filters[:]
        self._showwarning = self._module.showwarning
        if self._record:
            log = []

            def showwarning(*args, **kwargs):
                log.append(WarningMessage(*args, **kwargs))
            self._module.showwarning = showwarning
            return log
        else:
            return None 

def _showwarning(message, category, filename, lineno, file=None, line=None):
    """
    Implementation of showwarnings which redirects to logging, which will first
    check to see if the file parameter is None. If a file is specified, it will
    delegate to the original warnings implementation of showwarning. Otherwise,
    it will call warnings.formatwarning and will log the resulting string to a
    warnings logger named "py.warnings" with level logging.WARNING.
    """
    if file is not None:
        if _warnings_showwarning is not None:
            _warnings_showwarning(message, category, filename, lineno, file, line)
    else:
        s = warnings.formatwarning(message, category, filename, lineno, line)
        logger = getLogger("py.warnings")
        if not logger.handlers:
            logger.addHandler(NullHandler())
        logger.warning("%s", s) 

def _showwarning(message, category, filename, lineno, file=None, line=None):
    """
    Implementation of showwarnings which redirects to logging, which will first
    check to see if the file parameter is None. If a file is specified, it will
    delegate to the original warnings implementation of showwarning. Otherwise,
    it will call warnings.formatwarning and will log the resulting string to a
    warnings logger named "py.warnings" with level logging.WARNING.
    """
    if file is not None:
        if _warnings_showwarning is not None:
            _warnings_showwarning(message, category, filename, lineno, file, line)
    else:
        s = warnings.formatwarning(message, category, filename, lineno, line)
        logger = getLogger("py.warnings")
        if not logger.handlers:
            logger.addHandler(NullHandler())
        logger.warning("%s", s) 

def test_warnings(self):
        with warnings.catch_warnings():
            logging.captureWarnings(True)
            try:
                warnings.filterwarnings("always", category=UserWarning)
                file = cStringIO.StringIO()
                h = logging.StreamHandler(file)
                logger = logging.getLogger("py.warnings")
                logger.addHandler(h)
                warnings.warn("I'm warning you...")
                logger.removeHandler(h)
                s = file.getvalue()
                h.close()
                self.assertTrue(s.find("UserWarning: I'm warning you...\n") > 0)

                #See if an explicit file uses the original implementation
                file = cStringIO.StringIO()
                warnings.showwarning("Explicit", UserWarning, "dummy.py", 42,
                                        file, "Dummy line")
                s = file.getvalue()
                file.close()
                self.assertEqual(s,
                        "dummy.py:42: UserWarning: Explicit\n  Dummy line\n")
            finally:
                logging.captureWarnings(False) 

def _showwarning(message, category, filename, lineno, file=None, line=None):
    """
    Implementation of showwarnings which redirects to logging, which will first
    check to see if the file parameter is None. If a file is specified, it will
    delegate to the original warnings implementation of showwarning. Otherwise,
    it will call warnings.formatwarning and will log the resulting string to a
    warnings logger named "py.warnings" with level logging.WARNING.
    """
    if file is not None:
        if _warnings_showwarning is not None:
            _warnings_showwarning(message, category, filename, lineno, file, line)
    else:
        s = warnings.formatwarning(message, category, filename, lineno, line)
        logger = getLogger("py.warnings")
        if not logger.handlers:
            logger.addHandler(NullHandler())
        logger.warning("%s", s) 

def execute(self):
        def showwarning(message, category, filename, fileno, file=None, line=None):
            msg = warnings.formatwarning(message, category, filename, fileno, line)
            self.log.warning(msg.strip())

        with warnings.catch_warnings():
            warnings.simplefilter("always")
            warnings.showwarning = showwarning

            try:
                return self.run()
            except SystemExit:
                raise
            except:
                self.log.critical(traceback.format_exc().strip())
                sys.exit(1) 

def _showwarning(message, category, filename, lineno, file=None, line=None):
    """
    Implementation of showwarnings which redirects to logging, which will first
    check to see if the file parameter is None. If a file is specified, it will
    delegate to the original warnings implementation of showwarning. Otherwise,
    it will call warnings.formatwarning and will log the resulting string to a
    warnings logger named "py.warnings" with level logging.WARNING.
    """
    if file is not None:
        if _warnings_showwarning is not None:
            _warnings_showwarning(message, category, filename, lineno, file, line)
    else:
        s = warnings.formatwarning(message, category, filename, lineno, line)
        logger = getLogger("py.warnings")
        if not logger.handlers:
            logger.addHandler(NullHandler())
        logger.warning("%s", s) 

def test_warnings(self):
        with warnings.catch_warnings():
            logging.captureWarnings(True)
            try:
                warnings.filterwarnings("always", category=UserWarning)
                file = cStringIO.StringIO()
                h = logging.StreamHandler(file)
                logger = logging.getLogger("py.warnings")
                logger.addHandler(h)
                warnings.warn("I'm warning you...")
                logger.removeHandler(h)
                s = file.getvalue()
                h.close()
                self.assertTrue(s.find("UserWarning: I'm warning you...\n") > 0)

                #See if an explicit file uses the original implementation
                file = cStringIO.StringIO()
                warnings.showwarning("Explicit", UserWarning, "dummy.py", 42,
                                        file, "Dummy line")
                s = file.getvalue()
                file.close()
                self.assertEqual(s,
                        "dummy.py:42: UserWarning: Explicit\n  Dummy line\n")
            finally:
                logging.captureWarnings(False) 

def install_warning_logger():
    # Enable our Deprecation Warnings
    warnings.simplefilter("default", PipDeprecationWarning, append=True)

    global _warnings_showwarning

    if _warnings_showwarning is None:
        _warnings_showwarning = warnings.showwarning
        warnings.showwarning = _showwarning 

def _collectWarnings(observeWarning, f, *args, **kwargs):
    """
    Call C{f} with C{args} positional arguments and C{kwargs} keyword arguments
    and collect all warnings which are emitted as a result in a list.

    @param observeWarning: A callable which will be invoked with a L{_Warning}
        instance each time a warning is emitted.

    @return: The return value of C{f(*args, **kwargs)}.
    """
    def showWarning(message, category, filename, lineno, file=None, line=None):
        assert isinstance(message, Warning)
        observeWarning(_Warning(
                str(message), category, filename, lineno))

    # Disable the per-module cache for every module otherwise if the warning
    # which the caller is expecting us to collect was already emitted it won't
    # be re-emitted by the call to f which happens below.
    _setWarningRegistryToNone(sys.modules)

    origFilters = warnings.filters[:]
    origShow = warnings.showwarning
    warnings.simplefilter('always')
    try:
        warnings.showwarning = showWarning
        result = f(*args, **kwargs)
    finally:
        warnings.filters[:] = origFilters
        warnings.showwarning = origShow
    return result 

def install_warning_logger():
    # Enable our Deprecation Warnings
    warnings.simplefilter("default", PipDeprecationWarning, append=True)

    global _warnings_showwarning

    if _warnings_showwarning is None:
        _warnings_showwarning = warnings.showwarning
        warnings.showwarning = _showwarning 

def install_warning_logger():
    # Enable our Deprecation Warnings
    warnings.simplefilter("default", PipDeprecationWarning, append=True)

    global _warnings_showwarning

    if _warnings_showwarning is None:
        _warnings_showwarning = warnings.showwarning
        warnings.showwarning = _showwarning 

def install_warning_logger():
    # Enable our Deprecation Warnings
    warnings.simplefilter("default", PipDeprecationWarning, append=True)

    global _warnings_showwarning

    if _warnings_showwarning is None:
        _warnings_showwarning = warnings.showwarning
        warnings.showwarning = _showwarning 

def __enter__(self):
        if self._entered:
            raise RuntimeError("cannot enter suppress_warnings twice.")

        self._orig_show = warnings.showwarning
        self._filters = warnings.filters
        warnings.filters = self._filters[:]

        self._entered = True
        self._tmp_suppressions = []
        self._tmp_modules = set()
        self._forwarded = set()

        self.log = []  # reset global log (no need to keep same list)

        for cat, mess, _, mod, log in self._suppressions:
            if log is not None:
                del log[:]  # clear the log
            if mod is None:
                warnings.filterwarnings(
                    "always", category=cat, message=mess)
            else:
                module_regex = mod.__name__.replace('.', r'\.') + '$'
                warnings.filterwarnings(
                    "always", category=cat, message=mess,
                    module=module_regex)
                self._tmp_modules.add(mod)
        warnings.showwarning = self._showwarning
        self._clear_registries()

        return self 

def __enter__(self):
        if self._entered:
            raise RuntimeError("cannot enter suppress_warnings twice.")

        self._orig_show = warnings.showwarning
        self._filters = warnings.filters
        warnings.filters = self._filters[:]

        self._entered = True
        self._tmp_suppressions = []
        self._tmp_modules = set()
        self._forwarded = set()

        self.log = []  # reset global log (no need to keep same list)

        for cat, mess, _, mod, log in self._suppressions:
            if log is not None:
                del log[:]  # clear the log
            if mod is None:
                warnings.filterwarnings(
                    "always", category=cat, message=mess)
            else:
                module_regex = mod.__name__.replace('.', r'\.') + '$'
                warnings.filterwarnings(
                    "always", category=cat, message=mess,
                    module=module_regex)
                self._tmp_modules.add(mod)
        warnings.showwarning = self._showwarning
        self._clear_registries()

        return self 

def __exit__(self, *exc_info):
        warnings.showwarning = self._orig_show
        warnings.filters = self._filters
        self._clear_registries()
        self._entered = False
        del self._orig_show
        del self._filters 

def install_warning_logger():
    # type: () -> None
    # Enable our Deprecation Warnings
    warnings.simplefilter("default", PipDeprecationWarning, append=True)

    global _original_showwarning

    if _original_showwarning is None:
        _original_showwarning = warnings.showwarning
        warnings.showwarning = _showwarning 

def __exit__(self, *exc_info):
        warnings.showwarning = self._orig_show
        warnings.filters = self._filters
        self._clear_registries()
        self._entered = False
        del self._orig_show
        del self._filters 

def captureWarnings(capture):
    """
    If capture is true, redirect all warnings to the logging package.
    If capture is False, ensure that warnings are not redirected to logging
    but to their original destinations.
    """
    global _warnings_showwarning
    if capture:
        if _warnings_showwarning is None:
            _warnings_showwarning = warnings.showwarning
            warnings.showwarning = _showwarning
    else:
        if _warnings_showwarning is not None:
            warnings.showwarning = _warnings_showwarning
            _warnings_showwarning = None 

def __enter__(self):
        if self._entered:
            raise RuntimeError("cannot enter suppress_warnings twice.")

        self._orig_show = warnings.showwarning
        self._filters = warnings.filters
        warnings.filters = self._filters[:]

        self._entered = True
        self._tmp_suppressions = []
        self._tmp_modules = set()
        self._forwarded = set()

        self.log = []  # reset global log (no need to keep same list)

        for cat, mess, _, mod, log in self._suppressions:
            if log is not None:
                del log[:]  # clear the log
            if mod is None:
                warnings.filterwarnings(
                    "always", category=cat, message=mess)
            else:
                module_regex = mod.__name__.replace('.', r'\.') + '$'
                warnings.filterwarnings(
                    "always", category=cat, message=mess,
                    module=module_regex)
                self._tmp_modules.add(mod)
        warnings.showwarning = self._showwarning
        self._clear_registries()

        return self 

def install_warning_logger():
    # type: () -> None
    # Enable our Deprecation Warnings
    warnings.simplefilter("default", PipDeprecationWarning, append=True)

    global _original_showwarning

    if _original_showwarning is None:
        _original_showwarning = warnings.showwarning
        warnings.showwarning = _showwarning 

def capture_warnings(capture):
    "Replace warning.showwarning with idle_showwarning, or reverse."

    global _warnings_showwarning
    if capture:
        if _warnings_showwarning is None:
            _warnings_showwarning = warnings.showwarning
            warnings.showwarning = idle_showwarning
    else:
        if _warnings_showwarning is not None:
            warnings.showwarning = _warnings_showwarning
            _warnings_showwarning = None 

def test_warningToFile(self):
        """
        L{twisted.python.log.showwarning} passes warnings with an explicit file
        target on to the underlying Python warning system.
        """
        message = "another unique message"
        category = FakeWarning
        filename = "warning-filename.py"
        lineno = 31

        output = StringIO()
        log.showwarning(message, category, filename, lineno, file=output)

        self.assertEqual(
            output.getvalue(),
            warnings.formatwarning(message, category, filename, lineno))

        # In Python 2.6 and higher, warnings.showwarning accepts
        # a "line" argument which gives the source line the warning
        # message is to include.
        line = "hello world"
        output = StringIO()
        log.showwarning(message, category, filename, lineno, file=output,
                        line=line)

        self.assertEqual(
            output.getvalue(),
            warnings.formatwarning(message, category, filename, lineno,
                                   line))