bug#72830: Big rectangular selections are slow

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

> Sorry if I've lost track with your step numbering, but the problem is still
> that we extract and retain the selected text both at selection and each
> incremental modification of it.

"incremental modification" is my step 2.  And in the design, step
2 should not actually compute the content of the selection.
IOW, what you describe sounds like a plain bug.

> So the extraction needs to be delayed until either requested by the X server
> or locally by mouse-yank-primary. This means that we need to decide whether
> it would be a problem to do so, as the buffer may have changed between the
> selection and text extraction. (I think we shouldn't bother preserving
> PRIMARY data across buffer modification.)

Modifications deactivate the selection, so if we want to preserve the
selection until after modifications, that's when step 4 comes into play.


        Stefan