Re: fix for bug 10994 breaks ido customizations in major way

["Óscar Fuentes" <ofv@wanadoo.es>]

Le Wang <l26wang@gmail.com> writes:

> On Sat, May 4, 2013 at 4:33 AM, Leo Liu <sdl.web@gmail.com> wrote:
>
>> On 2013-05-03 20:49 +0800, Le Wang wrote:
>> > There are a few ido customizations floating around that propertizes text.
>> >  This will break all of them.  I don't think this fix is acceptable.
>>
>> That I wouldn't know. I only know what is in emacs and that the fix has
>> been in use for a while.  Feel free to propose a different fix
>>
>
> Sure, I've attached a patch that deletes duplicates.

This change introduces a serious slowdown which is noticeable for large
candidate lists (try with 10000 elements.) The slowdown happens on every
invocation.

It is obvious that having duplicate candidates makes no sense, but at
the same time scanning the list in advance for all duplicates is
expensive. I'll suggest detecting and removing the duplicates on the
navigation functions, maybe just the adjacent duplicates (using the list
as a ring.)

Another "fix" could be to require a duplicate-free list for
ido-complete.