Re: psql completion for ids in multibyte string

On Fri, Feb 26, 2016 at 6:34 PM, Kyotaro HORIGUCHI
<horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> Hello, this is the second patch plitted out. This allows
> multibyte names to be completed in psql.
>
> At Fri, 06 Nov 2015 11:47:17 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp> wrote
in<20151106.114717.170526268.horiguchi.kyotaro@lab.ntt.co.jp> 
>> At Thu, 5 Nov 2015 18:32:59 +0900, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> wrote in
<563B224B.3020400@lab.ntt.co.jp>
>> > On 2015/11/05 18:10, Kyotaro HORIGUCHI wrote:
>> > > Hello. I don't know whether this is a bug fix or improvement,
>> >
>> > Would it be 50-50? :-)
>>
>> Yeah, honestly saying, I doubt that this is valuable but feel
>> uneasy to see some of the candidates vanish as completon proceeds
>> for no persuasive reason.

+1 from me, it's entirely reasonable to want to name database objects
in any human language and use auto-completion.  It's not working today
as you showed.

> The current version of tab-completion failed to complete names
> with multibyte characters.
>
> =# create table いろは (あ int);
> =# create table いこい (あ int);
> =# drop table <tab>
> "いろは"             hint_plan.           pg_toast.
> "いこい"             information_schema.  pg_toast_temp_1.
> ALL IN TABLESPACE    pg_catalog.          public.
> dbms_stats.          pg_temp_1.
> postgres=# alter table "い
> =# drop table "い<tab>
> =# drop table "い           /* No candidate offered */
>
> This is because _complet_from_query counts the string length in
> bytes, instead of characters. With this patch the candidates will
> appear.
>
> =# drop table "い<tab>
> "いこい"  "いろは"
> postgres=# drpo table "い

The patch looks correct to me: it counts characters rather than bytes,
which is the right thing to do because the value is passed to substr()
which also works in characters rather than bytes.  I tested with
"éclair", and without the patch, tab completion doesn't work if you
press tab after 'é'.  With the patch it does.

--
Thomas Munro
http://www.enterprisedb.com