DataMapper::Repository#read with an invalid query returns an ambiguous result

[halorgium]

If you ask a Repository to read the records for a valid query which returns an empty set, you get an empty set.
If you ask a Repository to read the records for an invalid query, you get an empty set.

It is impossible to determine the difference between these results.

Can we change the behaviour for an invalid query to raise an error?

https://github.com/datamapper/dm-core/blob/master/lib/dm-core/repository.rb#L160-163

[solnic]

Yes there were some discussions about that already and yes we want to change that behavior. Can't say when exactly it'll happen tho but I think it's safe to assume this change will make it into release 1.2.

[halorgium]

Is there any reason why someone should be relying on the current behaviour with an invalid query?
It would seem that changing this would only make it less likely that people are hitting cases where their queries are not actually executed.

[mbj]

@solnic, @emmanuel. Id like to tackle this since I was bid by this multiple times. It has become better since we merged the "raise on invalid property" patches but you can still easily create an invalid query. You'll accept a pull request for 1.3?

[solnic]

@mbj sure man!

[tpitale]

@mbj Any interest in tackling this still?

[tpitale]

Oh wait, I did add a PR … #295.

[mbj]

@mbj Any interest in tackling this still?

No, sorry.