bug#50431: revert-buffer doesn't preserve read-onlyness

[Lars Ingebrigtsen <larsi@gnus.org>]

Richard Stallman <rms@gnu.org> writes:

> How about just this: keep buffer-read-only unchanged?
>
> If it differs from the file's permissions, almost certainly
> the user changed it and will beglad of revert-buffer preserves it.

Yes, but that's my point -- we need to store the file's permissions
somewhere so that we can see whether buffer-read-only was set/unset
because of that or not.  (Since the file's permissions may change
afterwards.)

> The other case is that the file permissions have been changed
> since visiting the file.  But users won't be shocked if
> revert-buffer fails to change buffer-read-only in that case,
> and they will know what to do.

No, people have work flows that depend on revert-buffer updating the
readedness based on the file's readedness, and this would disrupt that.
And there's no need to.  We just have to do a small bit of programming.  :-)

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