bug#60333: [PATCH] whitespace: Update bob, eob markers in base and indirect buffers

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

>> +(defvar whitespace--indirect-buffers nil
>> +  "Plist mapping a base buffer to a list of its indirect buffers.
>> +Used to work around Bug#46982.")
> Org uses a similar variable for similar purposes.
> Would it make more sense to expose the list of indirect buffers for a
> given buffer in more centralized way?

"Expose" is the wrong term, because we don't have that info ready to
be exposed.  We'd either have to create&maintain that list, or compute
it on-demand when requested.

We could export some way for ELisp to check if BUFFER is the base buffer
of some other indirect buffers so as to skip the loop through
`buffer-list` in the common case.  So that sane code (i.e. code which
doesn't use indirect buffers) doesn't pay for the careless users of that
anti-feature :-)

If it weren't for backward compatibility, I'd suggest to make
`buffer-base-buffer` return t (rather than nil) when BUFFER is the base
buffer of other indirect buffers.


        Stefan