Fix of Max Choices bug

[pjpassa]

Max choices used to only send data to the front end if the total number of instances of the model was less than the max choices setting.

I refactored the code so that the set was created earlier. This way the view will return data if the number of unique values is less than the max choices setting.

[coveralls]

Coverage decreased (-0.007%) to 96.19% when pulling 2b124aa75688e9260291f3d1df8d9830a7d149d0 on worthwhile:feat/max-choices-fix into 119c76d7198b84148f5662face3e62af9241895b on modlinltd:develop.

[asfaltboy]

Hi @pjpassa, thanks for the contribution! This fix makes sense but, I'm worried about potentially harmful performance if the query will return a very large number of values. That was the reason we used query.count() instead, to avoid potentially fetching large amount of values just to count them.

What if we order_by(field.name).distinct().count() instead? For our simple query this should work correctly I believe.

Additionally, I would add a more specific test case, for example leaving the existing name with identical 5 names, and asserting the view returns the 1 distinct name. Later, randomizing the names (or using ID field), and asserting the max limit is reached.

[coveralls]

Coverage decreased (-2.1%) to 94.095% when pulling dbed972ee7b524c86224ce5c30989e7637fa2e9b on worthwhile:feat/max-choices-fix into 119c76d7198b84148f5662face3e62af9241895b on modlinltd:develop.

[coveralls]

Coverage decreased (-0.007%) to 96.19% when pulling dbed972ee7b524c86224ce5c30989e7637fa2e9b on worthwhile:feat/max-choices-fix into 119c76d7198b84148f5662face3e62af9241895b on modlinltd:develop.