:count yields wrong result

[NobodysNightmare]

Reproduction

Model.create_100_entries
Model.page(1).per_page(10).count

Expected

=> 10

Actual

=> 100

Explanation

From an ActiveRecord perspective I am holding a Relation, that results in 10 records being returned. I don't understand, how the count for this relation could be higher.
Or to write it as rspec expectation:

relation = Model.page(1).per_page(10)
expect(relation.count).to eql relation.to_a.count

Workaround?

If (for some reason) this problem is not as easily solvable:
Is there a work around? The best solution I could find is calling to_a, which of course will perform the full SQL query.

[joaozig]

When you use Model.count, ActiveRecord performs a SELECT COUNT, ignoring any limit parameter.

In this case, you can use:
relation = Model.page(1).per_page(10)
expect(relation.length).to eql(10)
or
relation = Model.page(1).per_page(10)
expect(relation.size).to eql(10)

.length will avoid another db query, but you must previously load the collection.
.size seems to be the best option because if the collection has already been loaded, it will return its length just like calling .length. If it hasn't been loaded yet, it's like calling .count.

you can read more about that here:
http://blog.hasmanythrough.com/2008/2/27/count-length-size
http://stackoverflow.com/questions/6083219/activerecord-size-vs-count