[python-committers] Adding a hidden field to BaseException going to break the ABI?

[Brett Cannon]

issue6844 wants to stop a warning from being raised when someone
accesses a 'message' attribute on an exception when it is set by the
user (currently any usage of the 'message' attribute raises a
warning). To do this properly is going to require some state flag on
BaseException's struct. But I don't know if that constitutes breaking
the ABI during a micro release or not. I figure no but I wanted to
double-check.

-Brett