Method _format_exception_only

IPython/core/ultratb.py:743–813

Format the exception part of a traceback. The arguments are the exception type and value such as given by sys.exc_info()[:2]. The return value is a list of strings, each ending in a newline. Normally, the list contains a single string; however, for SyntaxError excep

(self, etype, value)

        return list

    def _format_exception_only(self, etype, value):
        """Format the exception part of a traceback.

        The arguments are the exception type and value such as given by
        sys.exc_info()[:2]. The return value is a list of strings, each ending
        in a newline.  Normally, the list contains a single string; however,
        for SyntaxError exceptions, it contains several lines that (when
        printed) display detailed information about where the syntax error
        occurred.  The message indicating which exception occurred is the
        always last string in the list.

        Also lifted nearly verbatim from traceback.py
        """
        have_filedata = False
        Colors = self.Colors
        list = []
        stype = py3compat.cast_unicode(Colors.excName + etype.__name__ + Colors.Normal)
        if value is None:
            # Not sure if this can still happen in Python 2.6 and above
            list.append(stype + '\n')
        else:
            if issubclass(etype, SyntaxError):
                have_filedata = True
                if not value.filename: value.filename = "<string>"
                if value.lineno:
                    lineno = value.lineno
                    textline = linecache.getline(value.filename, value.lineno)
                else:
                    lineno = 'unknown'
                    textline = ''
                list.append('%s  File %s"%s"%s, line %s%s%s\n' % \
                            (Colors.normalEm,
                             Colors.filenameEm, py3compat.cast_unicode(value.filename), Colors.normalEm,
                             Colors.linenoEm, lineno, Colors.Normal  ))
                if textline == '':
                    textline = py3compat.cast_unicode(value.text, "utf-8")

                if textline is not None:
                    i = 0
                    while i < len(textline) and textline[i].isspace():
                        i += 1
                    list.append('%s    %s%s\n' % (Colors.line,
                                                  textline.strip(),
                                                  Colors.Normal))
                    if value.offset is not None:
                        s = '    '
                        for c in textline[i:value.offset - 1]:
                            if c.isspace():
                                s += c
                            else:
                                s += ' '
                        list.append('%s%s^%s\n' % (Colors.caret, s,
                                                   Colors.Normal))

            try:
                s = value.msg
            except Exception:
                s = self._some_str(value)