Accept arguments for #count

[DanielVartanov]

Sometimes it is needed to call relation.count(distinct: true). I am not sure what is the best way to test it within will_paginate's testing conventions. Can you guys give me some advice?

Thanks in advance.

[mislav]

Why do you need to count distinct entries on a paginated collection?

will_paginate's testing conventions aren't anything special. You set up some data in the database (I use fixtures), then call the method and assert that you got the value you expected.

I'm not happy with the current hack I did for count, but it was needed to work around some Active Record bugs. Since count accepts arguments and I seem to have broken that, your fix is in order.

[DanielVartanov]

Why do you need to count distinct entries on a paginated collection?

I came up with a request which I have to denote disctinct: true for in order to get a correct result.

Honestly, I believe that it is a bug of ActiveRecord (relation.uniq.count.to_sql returns SELECT COUNT(id) instead of SELECT COUNT(DISTINCT id)). I will try to fix it in AR, but anyway it is useful for will_paginate to reflect actual AR syntax.

So, for now I should write tests and it will be enough, correct?

[mislav]

If AR Relation accepts arguments to count, I definitely want to forward them. It doesn't matter so much what they are. Please add tests for this

[DanielVartanov]

Ok! I'll be back with tests soon.

[cyrusstoller]

+1

Want to be able to pass count(:all) due to rails/rails#10710

[nathany]

Need to same feature for the same reason as @cyrusstoller.

Thanks @DanielVartanov.

[nathany]

@DanielVartanov Are you adding tests for this and rebasing to master?

[DanielVartanov]

@nathany procrastinating, unfortunately. I publicly announce, that it will be done by June 2nd, 00:00 UTC.

I offer to put me in shame if I don't! But I will :-)

[nathany]

😄

[DanielVartanov]

@mislav Please review the updated commit (sorry for a force-push).

[nathany]

Thanks @DanielVartanov. There is still another issue with count internally from will_paginate if there is a select scope.

It can be fixed with count(:all) but I'm not sure how far back Rails supports that syntax and how far back will_paginate intends to support with this version.

[mislav]

I wish this test was more solid. It should assert the result of count. The data and the query should be set up in a way that makes count() yield different results depending on whether it was with or without arguments. This way we're sure that the arguments really got forwarded and that the correct SQL query was executed. Then there will be no need for inspecting the query directly on the next line.

Also, if such test passes on CI, we are confident that it works in all combinations of Active Record + db adapter versions.

[mislav]

In the end I removed this test before merging, since it didn't yield the same results on all Rails versions that we test with (~ half of them failed)