bug#9185: 24.0.50; "C-s M-p" does not bring the tip of the search ring

[Juri Linkov <juri@jurta.org>]

>> But I've found another use-case that seems to need a fix too:
>> 0. C-s a <RET> C-s b <RET> C-s c <RET>
>> 1. C-s C-s     --> "c" is selected, OK.
>> 2. M-p <RET>   --> "b" is selected, OK.
>> 3. M-p         --> Now "c" (the previous used entry) should have been
>> selected, but I see that "b" (the current entry) remains selected
>> instead.
>
> This is a separate problem caused when exiting from the minibuffer in
> `isearch-edit-string' by `read-from-minibuffer' (i.e. step 2
> `M-p <RET>' above) adds a new element "b" to the history (search ring).
>
> I agree that `isearch-edit-string' should not update the search ring.
> It should be updated only by `isearch-update-ring' in `isearch-done'.
> So e.g. `C-s C-s M-e RET C-g' or `C-s M-p RET C-g' should keep the
> search ring unchanged.  Note also that `isearch-done' with the arg
> NOPUSH=t already tries to take care of not updating the search ring,
> but unsuccessfully.  It requires the following patch for the complete fix:

I noticed now that `isearch-edit-string' should not add new elements
to the search ring, but should allow old elements to be deleted
from the search ring with a command like `delete-history-element'
(published in http://thread.gmane.org/gmane.emacs.devel/24353/focus=25269)
So I installed another fix that let-binds `history-add-new-input' to nil.