bug#13594: Planning Emacs-24.4

[Stefan Monnier]

>> Implemented as requested. I have also briefly tested with ggtags and it
>> worked.  Comments welcome.  Thanks.

Thank you.  Two comments:
1- You can/should use nil instead of `ignore'.
2- I'm not sure `may-fail' is the right name.  After all, it's not
   really a failure, but rather a conscious (and successful) decision to
   not display the buffer.  I don't have a good counter-proposition, tho
   ("no-display-ok" is what comes to my mind, but I don't like it too
   much either).

> Why didn't you implement the may-fail part?  IIUC `display-buffer'
> should *not* return nil unless may-fail has been set.  So if may-fail is
> not set, `display-buffer' should either create a new window, a new
> frame, or reuse some window at any cost.

AFAICT, display-buffer does already try pretty hard.  I think that if
display-buffer returns nil in a context where may-fail is nil, it's not
a bug in display-buffer but in some of the ACTIONS, and I see no reason
why `display-buffer' should try and cover up the problem.

> And there's no use for `display-buffer' returning t.

You mean, it should return nil (and never t) if the return value is not
a window?
I guess it would indeed be cleaner, yes,


        Stefan