Fix Hidden fields triggering error when using getSingleScalarResult()

[Mediagone]

Using HIDDEN fields in a request was causing the "unicity" check to fail and throw a NonUniqueResultException, because we were counting raw data instead of counting gathered row data.

See #4257 for original issue.

PS: sorry if I've done something wrong in the contribution procedure, it's my first pull request :)

[Mediagone]

I didn't add "use function" statements because there was none in the original file, but I see errors in the commit.
Should I add them?

[beberlei]

@Mediagone i don't understand what you mean with HIDDEN fields? This behavior here is the same that DBAL and by extension PDO have when you use Statement->fetchColumn() on a row with more results. It returns just the first one, and that is to be expected at the moment.

If we want this to change, it would be a BC break.

[Mediagone]

Hi @beberlei , let's take this example:

SELECT 
  COUNT(u.id) AS count, 
  (u.posts_count + u.likes_count) AS HIDDEN score
FROM User u
HAVING score > 10

In this case, getScalarResult() will return an array of 1 result ("count"), because "score" is only used internally and not returned since it uses the HIDDEN DQL keyword.
However, getSingleScalarResult() will throw a NonUniqueResultException because it counts all selected fields, including hidden ones, despite the final result will discard hidden fields and return a single scalar.

[Mediagone]

Tests updated 🙂

[SenseException]

I'd like to see another reviewer checking the changes and if the tests are sufficient.

[beberlei]

thank you