Re: Rest interface: how to match empty fields

On Sun, Oct 06, 2019 at 12:19:57PM -0400, John P. Rouillard wrote:
> Hi all:
> 
> Does anybody have any ideas on how to ask a rest interface if a value
> is missing? I am working with multilinks specifically, but empty links
> or text fields are also a concern.

You can put "-1" for the ID.

> Use cases:
> 
>    issues that do not have a keyword value set (e.g. no keywords, or null)
-1 for the keyword multilink should do the trick.

>    issues that do not have the FirstTimeFailure (item #7) keyword set
> 
> This is also kind of an issue in the web interface IIRC. E.G. for
> links I can't say must not be item 4, I have to say must be
> -1,1,2,3,5,6,7,8,9. This obviously doesn't work for multilinks as I
> can have both link3 and link 4.

There is a hack that implements an expression parser using special
negative values (like -1 for no value, -2,... is used for specifying
boolean expressions like 'not', 'and', 'or'). See code in and around
_filter_multilink_expression in backends/rdbms_common.py.

There is unfortunately no regression test for this and the
implementation uses subselects (instead of an outer join) but, well, it
sort of works :-) I've encountered at least one case (which I can't
currently reproduce) where it fails when two such searches are
performed in the same query.

And, no, I don't know how to really use this, so a test to document how
to do that would be really nice (I didn't implement this feature :-)

Note that this is only implemented for Multilinks although I see no
reason why it couldn't work on Link, too.

Ralf
-- 
Dr. Ralf Schlatterbeck                  Tel:   +43/2243/26465-16
Open Source Consulting                  www:   http://www.runtux.com
Reichergasse 131, A-3411 Weidling       email: [email protected]