Python traceback.format_exception_only() Examples

def Start(self, callback):
        try:
            try:
                try:
                    self.result = eval(self.code, self.frame.f_globals, self.frame.f_locals)
                except SyntaxError:
                    exec self.code in self.frame.f_globals, self.frame.f_locals
                    self.result = ""
                self.hresult = 0
            except:
                l = traceback.format_exception_only(sys.exc_info()[0], sys.exc_info()[1])
                # l is a list of strings with trailing "\n"
                self.result = string.join(map(lambda s:s[:-1], l), "\n")
                self.hresult = winerror.E_FAIL
        finally:
            self.isComplete = 1
            callback.onComplete() 

def handle_exceptions(extype, value, tb):
    # Create traceback log
    lst = (traceback.format_tb(tb, None) +
        traceback.format_exception_only(extype, value))
    tracelog = '\nTraceback (most recent call last):\n' + "%-20s%s\n" % (
        "".join(lst[:-1]), lst[-1])

    if State.logger != None:
        pprint(tracelog)
    else:
        sys.stderr.write(tracelog)

        # Save to debug.log
        dbg = open(dfile(), 'w')
        dbg.write(tracelog)
        dbg.close()

###
# Install Px to startup 

def traceback_get_exception(num = -1):

    # build error message
    exception_string = ''.join(traceback.format_exception_only(sys.exc_type, hasattr(sys, 'exc_value') and sys.exc_value or 'Unknown'))

    # extract error location from traceback
    if hasattr(sys, 'exc_traceback'):
        (filename, line_number, function_name, text) = traceback.extract_tb(sys.exc_traceback)[num]
    else:
        (filename, line_number, function_name, text) = ('-', '-', '-', '-')

    error = {
        'message': exception_string,
        'location': {
            'filename': filename,
            'line_number': line_number,
            'function_name': function_name,
            'text': text,
            }
    }

    return error 

def do_pp(self, arg):
        """[width]pp expression
        Pretty-print the value of the expression.
        """
        width = getattr(arg, "cmd_count", None)
        try:
            val = self._getval(arg)
        except:
            return
        if width is None:
            try:
                width, _ = self.get_terminal_size()
            except Exception as exc:
                self.message("warning: could not get terminal size ({})".format(exc))
                width = None
        try:
            pprint.pprint(val, self.stdout, width=width)
        except:
            exc_info = sys.exc_info()[:2]
            self.error(traceback.format_exception_only(*exc_info)[-1].strip()) 

def filtered_traceback_format(tb_exception, chain=True):
    if chain:
        if tb_exception.__cause__ is not None:
            yield from filtered_traceback_format(tb_exception.__cause__, chain=chain)
            yield tb._cause_message
        elif (
            tb_exception.__context__ is not None
            and not tb_exception.__suppress_context__
        ):
            yield from filtered_traceback_format(tb_exception.__context__, chain=chain)
            yield tb._context_message
    yield "Traceback (most recent calls WITHOUT Sacred internals):\n"
    current_tb = tb_exception.exc_traceback
    while current_tb is not None:
        if not _is_sacred_frame(current_tb.tb_frame):
            stack = tb.StackSummary.extract(
                tb.walk_tb(current_tb), limit=1, lookup_lines=True, capture_locals=False
            )
            yield from stack.format()
        current_tb = current_tb.tb_next
    yield from tb_exception.format_exception_only()


# noinspection PyUnusedLocal 

def istrue(self):
        try:
            return self._istrue()
        except TEST_OUTCOME:
            self.exc = sys.exc_info()
            if isinstance(self.exc[1], SyntaxError):
                msg = [" " * (self.exc[1].offset + 4) + "^"]
                msg.append("SyntaxError: invalid syntax")
            else:
                msg = traceback.format_exception_only(*self.exc[:2])
            fail(
                "Error evaluating %r expression\n"
                "    %s\n"
                "%s" % (self._mark_name, self.expr, "\n".join(msg)),
                pytrace=False,
            ) 

def format_exc(limit=None, exception=None, tb_list=None):
    """
    This is like print_exc(limit) but returns a string instead of printing to a
    file.
    """
    result = ["Traceback (most recent call last):\n"]
    if exception is None:
        exception = get_context_with_traceback(get_async_context()).exception

    if tb_list is None:
        tb_list = extract_tb(limit)

    if tb_list:
        result.extend(traceback.format_list(tb_list))
        result.extend(traceback.format_exception_only(exception.__class__,
                                                      exception))
        return result
    else:
        return None 

def exceptionHandler(self, excType, exc, tb, systrace=False):
        if self.ui.catchNextExceptionBtn.isChecked():
            self.ui.catchNextExceptionBtn.setChecked(False)
        elif not self.ui.catchAllExceptionsBtn.isChecked():
            return
        
        self.currentTraceback = tb
        
        excMessage = ''.join(traceback.format_exception_only(excType, exc))
        self.ui.exceptionInfoLabel.setText(excMessage)

        if systrace:
            # exceptions caught using systrace don't need the usual 
            # call stack + traceback handling
            self.setStack(sys._getframe().f_back.f_back)
        else:
            self.setStack(frame=sys._getframe().f_back, tb=tb) 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def format_exc(self, limit=None):
        """
        This is like exception.print_exc(limit) but returns a string instead
        of printing to a file.
        """
        result = ["Traceback (most recent call last):\n"]

        tb_list = self._traceback

        if limit is not None:
            tb_list = tb_list[-limit:]

        result.extend(traceback.format_list(tb_list))

        if self.cause is not None:
            result.extend(traceback.format_exception_only(self.cause.__class__,
                                                          self.cause))
            return result
        else:
            return result 

def istrue(self):
        try:
            return self._istrue()
        except TEST_OUTCOME:
            self.exc = sys.exc_info()
            if isinstance(self.exc[1], SyntaxError):
                msg = [" " * (self.exc[1].offset + 4) + "^"]
                msg.append("SyntaxError: invalid syntax")
            else:
                msg = traceback.format_exception_only(*self.exc[:2])
            fail(
                "Error evaluating %r expression\n"
                "    %s\n"
                "%s" % (self._mark_name, self.expr, "\n".join(msg)),
                pytrace=False,
            ) 

def _do_row(self, insert_stmt, i, num_partitions):

        # Error callback for async requests
        def handle_errors(row, exc):
            self.num_request_done += 1
            try:
                name = type(exc).__name__
                self.exception_type[name] += 1
            except Exception as e:
                print(traceback.format_exception_only(type(e), e))

        # Success callback for async requests
        def success_callback(row):
            self.num_request_done += 1

        if i % self.update_stats_every == 0:
            self._print_write_status(i)

        row = row_generate(i, num_partitions)

        async_ret = self.session.execute_async(insert_stmt, row)
        errors = partial(handle_errors, row)
        async_ret.add_callbacks(success_callback, errors) 

def capture_exception(self, exc: Optional[BaseException] = None, user: Any = None,
                                context_env: Any = None,
                                severity: Optional[LogSeverity] = None):
        if exc:
            tb = exc.__traceback__
        else:
            _, exc, tb = sys.exc_info()
        exc_type: Any = type(exc)
        if severity is None:
            severity = LogSeverity.ERROR
        async with self.dbpool.acquire() as conn, conn.begin():
            query = error_logs.insert().values({
                'severity': severity,
                'source': 'manager',
                'user': user,
                'message': ''.join(traceback.format_exception_only(exc_type, exc)).strip(),
                'context_lang': 'python',
                'context_env': context_env,
                'traceback': ''.join(traceback.format_tb(tb)).strip()
            })
            await conn.execute(query)
        log.debug('Manager log collected: {}', str(exc)) 

def test_base_exception(self):
        # Test that exceptions derived from BaseException are formatted right
        e = KeyboardInterrupt()
        lst = traceback.format_exception_only(e.__class__, e)
        self.assertEqual(lst, ['KeyboardInterrupt\n'])

    # String exceptions are deprecated, but legal.  The quirky form with
    # separate "type" and "value" tends to break things, because
    #     not isinstance(value, type)
    # and a string cannot be the first argument to issubclass.
    #
    # Note that sys.last_type and sys.last_value do not get set if an
    # exception is caught, so we sort of cheat and just emulate them.
    #
    # test_string_exception1 is equivalent to
    #
    # >>> raise "String Exception"
    #
    # test_string_exception2 is equivalent to
    #
    # >>> raise "String Exception", "String Value"
    # 

def dump_exception(msg, f = sys.stdout, extra = None):
    exc_type, exc_value, exc_traceback = sys.exc_info()
    if isinstance(exc_value, StdException):
        cus_traceback = exc_value.traceback
    else:
        if hasattr(exc_value, 'traceback'):
            exc_traceback = exc_value.traceback
        cus_traceback = None
    f.write('%s %s:\n' % (datetime.now(), msg))
    f.write(SEPT)
    if cus_traceback != None:
        f.write('Traceback (most recent call last):\n')
        print_list(cus_traceback, file = f)
        f.write(format_exception_only(exc_type, exc_value)[0])
    else:
        print_exception(exc_type, exc_value, exc_traceback, file = f)
    f.write(SEPT)
    if extra != None:
        f.write(extra)
        f.write(SEPT)
    f.flush() 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def showtraceback(self):
        """Display the exception that just occurred.

        We remove the first stack item because it is our own code.

        The output is written by self.write(), below.

        """
        try:
            type, value, tb = sys.exc_info()
            sys.last_type = type
            sys.last_value = value
            sys.last_traceback = tb
            tblist = traceback.extract_tb(tb)
            del tblist[:1]
            list = traceback.format_list(tblist)
            if list:
                list.insert(0, "Traceback (most recent call last):\n")
            list[len(list):] = traceback.format_exception_only(type, value)
        finally:
            tblist = tb = None
        map(self.write, list) 

def write(self, source, value, depth=0):
        if depth == 0:
            value_string = pprint.pformat(value)
        else:
            try:
                value_string = repr(value)
            except Exception as e:
                exception_string = ''.join(
                    traceback.format_exception_only(type(e), e)
                ).strip()
                value_string = '<Exception in repr(): {}>'.format(exception_string)

        formatted = self.config.formatter.format_log_value(
            self.event, source, value_string, depth)
        self.config.write(formatted) 

def fallback_repr(self):
        try:
            info = ''.join(format_exception_only(*sys.exc_info()[:2]))
        except Exception:  # pragma: no cover
            info = '?'
        if PY2:
            info = info.decode('utf-8', 'ignore')
        return u'<span class="brokenrepr">&lt;broken repr (%s)&gt;' \
               u'</span>' % escape(info.strip()) 

def exception(self):
        """String representation of the exception."""
        buf = traceback.format_exception_only(self.exc_type, self.exc_value)
        rv = ''.join(buf).strip()
        return rv.decode('utf-8', 'replace') if PY2 else rv 

def test_unicode(self):
        err = AssertionError('\xff')
        lines = traceback.format_exception_only(type(err), err)
        self.assertEqual(lines, ['AssertionError: \xff\n'])

        err = AssertionError(u'\xe9')
        lines = traceback.format_exception_only(type(err), err)
        self.assertEqual(lines, ['AssertionError: \\xe9\n']) 

def format_error(self):
        """
        Format the error recieved from the other side and returns a list of
        strings.
        """
        lines = (['Exception in comms call {}:\n'.format(self.call_name)]
                 + traceback.format_list(self.tb)
                 + traceback.format_exception_only(self.etype, self.error))
        return lines 

def format_exception(self, event):
        lines = []
        exception_string = u''.join(traceback.format_exception_only(*event.arg[:2]))
        lines += [
            u'{c.red}!!! {line}{c.reset}'.format(
                c=self.c,
                line=line,
            )
            for line in exception_string.splitlines()
        ]
        lines += self.format_executing_node_exception(event)
        return lines 

def print_exception(type=None, value=None, tb=None, limit=None):
    if type is None:
        type, value, tb = sys.exc_info()
    import traceback
    print
    print "<H3>Traceback (most recent call last):</H3>"
    list = traceback.format_tb(tb, limit) + \
           traceback.format_exception_only(type, value)
    print "<PRE>%s<B>%s</B></PRE>" % (
        escape("".join(list[:-1])),
        escape(list[-1]),
        )
    del tb 

def get_exception_format(self, func, exc):
        try:
            func()
        except exc, value:
            return traceback.format_exception_only(exc, value) 

def test_string_exception1(self):
        str_type = "String Exception"
        err = traceback.format_exception_only(str_type, None)
        self.assertEqual(len(err), 1)
        self.assertEqual(err[0], str_type + '\n') 

def test_string_exception2(self):
        str_type = "String Exception"
        str_value = "String Value"
        err = traceback.format_exception_only(str_type, str_value)
        self.assertEqual(len(err), 1)
        self.assertEqual(err[0], str_type + ': ' + str_value + '\n') 

def test_unicode(self):
        err = AssertionError('\xff')
        lines = traceback.format_exception_only(type(err), err)
        self.assertEqual(lines, ['AssertionError: \xff\n'])

        err = AssertionError(u'\xe9')
        lines = traceback.format_exception_only(type(err), err)
        self.assertEqual(lines, ['AssertionError: \\xe9\n']) 

def test_without_exception(self):
        err = traceback.format_exception_only(None, None)
        self.assertEqual(err, ['None\n'])