Internal error when q is defined multiple times

[LucaDiba]

Hi team, the API returns 500 when calling GET /tracks?q=&q=foo (q defined multiple times where one time it's an empty string and another time it's not empty).

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Hi team, it looks like some query parameters in GET /tracks are not considered if q is undefined.

For example, specifying the genres correctly returns only the tracks of those genres.
However, adding created_at[from] doesn't change the result and always returns the same data.

I would expect all filters to be considered even if q is not defined.

Also, note that the API returns 500 when calling GET /tracks?q=&q=foo.

[LucaDiba]

Duplicate of #495 - definitely a caching issue since changing genres=dubstep to genres=dubstep,{random_string} returns the right data. Changing the created_at keeping the same random string returns the stale data. Looks like the cache entry is set after filtering on the creation date, however the cache key doesn't depend on the creation date.

Will keep this open for the internal error.