Re: Add SHELL_EXIT_CODE to psql

On Sat, Dec 31, 2022 at 5:28 PM Isaac Morland <isaac(dot)morland(at)gmail(dot)com>
wrote:

> On Sat, 31 Dec 2022 at 16:47, Corey Huinker <corey(dot)huinker(at)gmail(dot)com>
> wrote:
>
>>
>>> I wonder if there is value in setting up a psql on/off var
>>> SHELL_ERROR_OUTPUT construct that when set to "off/false"
>>> suppresses standard error via appending "2> /dev/null" (or "2> nul" if
>>> #ifdef WIN32). At the very least, it would allow for tests like this to be
>>> done with standard regression scripts.
>>>
>>
>> Thinking on this some more a few ideas came up:
>>
>> 1. The SHELL_ERROR_OUTPUT var above. This is good for simple situations,
>> but it would fail if the user took it upon themselves to redirect output,
>> and suddenly "myprog 2> /dev/null" works fine on its own but will fail when
>> we append our own "2> /dev/null" to it.
>>
>
> Rather than attempting to append redirection directives to the command,
> would it work to redirect stderr before invoking the shell? This seems to
> me to be more reliable and it should allow an explicit redirection in the
> shell command to still work. The difference between Windows and Unix then
> becomes the details of what system calls we use to accomplish the
> redirection (or maybe none, if an existing abstraction layer takes care of
> that - I'm not really up on Postgres internals enough to know), rather than
> what we append to the provided command.
>
>
Inside psql, it's a call to the system() function which takes a single
string. All output, stdout or stderr, is printed. So for the regression
test we have to compose a command that is OS appropriate AND suppresses
stderr.