Method format_messages_default

mypy/errors.py:1021–1078

Return a string list that represents the error messages. Use a form suitable for displaying to the user. If self.pretty is True also append a relevant trimmed source code line (only for severity 'error').

(
        self, error_tuples: list[ErrorTuple], source_lines: list[str] | None
    )

        )

    def format_messages_default(
        self, error_tuples: list[ErrorTuple], source_lines: list[str] | None
    ) -> list[str]:
        """Return a string list that represents the error messages.

        Use a form suitable for displaying to the user. If self.pretty
        is True also append a relevant trimmed source code line (only for
        severity 'error').
        """
        a: list[str] = []
        for file, line, column, end_line, end_column, severity, message, code in error_tuples:
            s = ""
            if file is not None:
                if self.options.show_column_numbers and line >= 0 and column >= 0:
                    srcloc = f"{file}:{line}:{1 + column}"
                    if self.options.show_error_end and end_line >= 0 and end_column >= 0:
                        srcloc += f":{end_line}:{end_column}"
                elif line >= 0:
                    srcloc = f"{file}:{line}"
                else:
                    srcloc = file
                s = f"{srcloc}: {severity}: {message}"
            else:
                s = message
            if (
                not self.hide_error_codes
                and code
                and (severity != "note" or code in SHOW_NOTE_CODES)
            ):
                # If note has an error code, it is related to a previous error. Avoid
                # displaying duplicate error codes.
                s = f"{s}  [{code}]"
            a.append(s)
            if self.options.pretty:
                # Add source code fragment and a location marker.
                if severity == "error" and source_lines and line > 0:
                    source_line = source_lines[line - 1]
                    source_line_expanded = source_line.expandtabs()
                    min_column = len(source_line) - len(source_line.lstrip())
                    if column < min_column:
                        # Something went wrong, take first non-empty column.
                        column = min_column

                    # Shifts column after tab expansion
                    column = len(source_line[:column].expandtabs())
                    end_column = len(source_line[:end_column].expandtabs())

                    # Note, currently coloring uses the offset to detect source snippets,
                    # so these offsets should not be arbitrary.
                    a.append(" " * DEFAULT_SOURCE_OFFSET + source_line_expanded)
                    marker = "^"
                    if end_line == line and end_column > column:
                        marker = f'^{"~" * (end_column - column - 1)}'
                    elif end_line != line:
                        # just highlight the first line instead
                        marker = f'^{"~" * (len(source_line_expanded) - column - 1)}'
                    a.append(" " * (DEFAULT_SOURCE_OFFSET + column) + marker)
        return a