bug#2553: *vc-diff* buffers are read-only, but M-k works

[Lars Magne Ingebrigtsen <larsi@gnus.org>]

Chong Yidong <cyd@stupidchicken.com> writes:

> The purpose of making the vc-diff buffer read-only (2007-11-10 change to
> vc.el) was so that people can use the read-only diff-mode bindings like
> "k" and "p".  However, it's counter-intuitive that undo does not work.
> Probably the easiest fix is to define a diff-undo command that lifts the
> read-only restriction temporarily.  Any thoughts?

Perhaps a more general solution would be possible here.  I think there
probably are other "mostly-read-only" modes where you have one or two
special commands that alter the buffer, anyway.  Like with `M-k'.
Perhaps there could be a buffer-local variable like
`undo-read-only-buffer' that if set, would allow `undo' to work in these
cases.

-- 
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  bloggy blog http://lars.ingebrigtsen.no/