Re: TestLib::command_fails_like enhancement - Mailing list pgsql-hackers

On 11/11/19 11:28 AM, Andrew Dunstan wrote:
> 
> On 11/11/19 1:27 PM, Mark Dilger wrote:
>>
>>
>> On 11/11/19 8:48 AM, Andrew Dunstan wrote:
>>>
>>> On 11/9/19 8:25 AM, Andrew Dunstan wrote:
>>>> OK, I agree that we're getting rather baroque here. I could go with
>>>> your
>>>> suggestion of YA function, or possibly a solution that simple passes
>>>> any
>>>> extra arguments straight through to IPC::Run::run(), e.g.
>>>>
>>>> command_fails_like(
>>>>         [ 'pg_dump', 'qqq', 'abc' ],
>>>>         qr/\Qpg_dump: error: too many command-line arguments (first is
>>>> "abc")\E/,
>>>>         'pg_dump: too many command-line arguments',
>>>>         '<pty<', \$eof_in);
>>>>
>>>> That means we're not future-proofing the function - we'll never be able
>>>> to add more arguments to it, but I'm not really certain that matters
>>>> anyway. I should note that perlcritic whines about subroutines with too
>>>> many arguments, so making provision for more seems unnecessary anyway.
>>>>
>>>> I don't think this is worth spending a huge amount of time on, we've
>>>> already spent more time discussing it than it would take to implement
>>>> either solution.
>>>>
>>>>
>>>
>>> On further consideration, I'm wondering why we don't just
>>> unconditionally use a closed input pty for all these functions (except
>>> run_log). None of them use any input, and making the client worry about
>>> whether or not to close it seems something of an abstraction break.
>>> There would be no API change at all involved in this case, just a bit of
>>> extra cleanliness. Would need testing on Windows, I'll go and do that
>>> now.
>>>
>>>
>>> Thoughts?
>>
>> That sounds a lot better than your previous patch.
>>
>> PostgresNode.pm and TestLib.pm both invoke IPC::Run::run.  If you
>> change all the invocations in TestLib to close input pty, should you
>> do the same for PostgresNode?  I don't have a strong argument for
>> doing so, but it seems cleaner to have both libraries invoking
>> commands under identical conditions, such that if commands were
>> borrowed from one library and called from the other they would behave
>> the same.
>>
>> PostgresNode already uses TestLib, so perhaps setting up the
>> environment can be abstracted into something, perhaps TestLib::run,
>> and then used everywhere that IPC::Run::run currently is used.
> 
> 
> 
> I don't think we need to do that. In the case of the PostgresNode.pm
> uses we know what the executable is, unlike the the TestLib.pm cases.
> They are our own executables and we don't expect them to be doing
> anything funky with /dev/tty.

Ok.  I think your proposal sounds fine.

-- 
Mark Dilger