Обсуждение: psql: fix variable existence tab completion

On 2024-03-03 03:00 +0100, Steve Chavez wrote:
> psql has the :{?name} syntax for testing a psql variable existence.
> 
> But currently doing \echo :{?VERB<Tab> doesn't trigger tab completion.
> 
> This patch fixes it. I've also included a TAP test.

Thanks.  The code looks good, all tests pass, and the tab completion
works as expected when testing manually.

-- 
Erik

On Sun, Mar 3, 2024 at 5:37 PM Erik Wienhold <ewie@ewie.name> wrote:
> On 2024-03-03 03:00 +0100, Steve Chavez wrote:
> > psql has the :{?name} syntax for testing a psql variable existence.
> >
> > But currently doing \echo :{?VERB<Tab> doesn't trigger tab completion.
> >
> > This patch fixes it. I've also included a TAP test.
>
> Thanks.  The code looks good, all tests pass, and the tab completion
> works as expected when testing manually.

A nice improvement.  I've checked why we have at all the '{' at
WORD_BREAKS and if we're going to break anything by removing that.  It
seems that '{' here from the very beginning and it comes from the
default value of rl_basic_word_break_characters [1].  It seems that
:{?name} is the only usage of '{' sign in psql.  So, removing it from
WORD_BREAKS shouldn't break anything.

I'm going to push this patch if no objections.

Links.
1. https://tiswww.case.edu/php/chet/readline/readline.html#index-rl_005fbasic_005fword_005fbreak_005fcharacters

------
Regards,
Alexander Korotkov

Hello!

On 14.03.2024 17:57, Alexander Korotkov wrote:
> On Sun, Mar 3, 2024 at 5:37 PM Erik Wienhold <ewie@ewie.name> wrote:
>> On 2024-03-03 03:00 +0100, Steve Chavez wrote:
>>> psql has the :{?name} syntax for testing a psql variable existence.
>>>
>>> But currently doing \echo :{?VERB<Tab> doesn't trigger tab completion.
>>>
>>> This patch fixes it. I've also included a TAP test.
>>
>> Thanks.  The code looks good, all tests pass, and the tab completion
>> works as expected when testing manually.

I'm not sure if Debian 10 is actual for the current master. But, if this is the case,
i suggest a patch, since the test will not work under this OS.
The thing is that, Debian 10 will backslash curly braces and the question mark and
TAB completion will lead to the string like that:

\echo :\{\?VERBOSITY\}

instead of expected:

\echo :{?VERBOSITY}

The patch attached fix the 010_tab_completion.pl test in the same way like [1].

With the best regards,

-- 
Anton A. Melnikov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

[1] https://www.postgresql.org/message-id/960764.1643751011@sss.pgh.pa.us

Hi, Anton!

On Mon, May 6, 2024 at 9:05 AM Anton A. Melnikov
<a.melnikov@postgrespro.ru> wrote:
> On 14.03.2024 17:57, Alexander Korotkov wrote:
> > On Sun, Mar 3, 2024 at 5:37 PM Erik Wienhold <ewie@ewie.name> wrote:
> >> On 2024-03-03 03:00 +0100, Steve Chavez wrote:
> >>> psql has the :{?name} syntax for testing a psql variable existence.
> >>>
> >>> But currently doing \echo :{?VERB<Tab> doesn't trigger tab completion.
> >>>
> >>> This patch fixes it. I've also included a TAP test.
> >>
> >> Thanks.  The code looks good, all tests pass, and the tab completion
> >> works as expected when testing manually.
>
> I'm not sure if Debian 10 is actual for the current master. But, if this is the case,
> i suggest a patch, since the test will not work under this OS.
> The thing is that, Debian 10 will backslash curly braces and the question mark and
> TAB completion will lead to the string like that:
>
> \echo :\{\?VERBOSITY\}
>
> instead of expected:
>
> \echo :{?VERBOSITY}
>
> The patch attached fix the 010_tab_completion.pl test in the same way like [1].

Thank you for the fix.  As I get, the fix teaches
010_tab_completion.pl to tolerate the invalid result of tab
completion.  Do you think we could fix it another way to make the
result of tab completion correct?

------
Regards,
Alexander Korotkov
Supabase

Hi, Alexander!

On 06.05.2024 13:19, Alexander Korotkov wrote:
>> The patch attached fix the 010_tab_completion.pl test in the same way like [1].
> 
> Thank you for the fix.  As I get, the fix teaches
> 010_tab_completion.pl to tolerate the invalid result of tab
> completion.  Do you think we could fix it another way to make the
> result of tab completion correct?

Right now i don't see any straight way to fix this to the correct tab completion.
There are several similar cases in this test.
E.g., for such a commands:
  
  CREATE TABLE "mixedName" (f1 int, f2 text);
  select * from "mi<TAB> ;

gives with debian 10:
postgres=# select * from \"mixedName\" ;

resulting in an error.
  
Now there is a similar workaround in the 010_tab_completion.pl with regex: qr/"mixedName\\?" /

I think if there were or will be complaints from users about this behavior in Debian 10,
then it makes sense to look for more complex solutions that will fix a backslash substitutions.
If no such complaints, then it is better to make a workaround in test.

With the best wishes,

-- 
Anton A. Melnikov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company