Redmine

Only three sorting criteria can be selected on the query edit screen.
With code before r16390, only three items could be saved as data according to screen specifications.

However, since "slice(0,3)" was changed to "slice!(3)" at r16390, the following result is returned now.

# slice(0,3)
sort_criteria = [['priority', 'desc'], ['tracker', 'asc'], ['priority', 'asc'], ['id', 'asc'], ['project', 'asc'], ['subject', 'asc']]
p sort_criteria.slice(0,3)
=> [['priority', 'desc'], ['tracker', 'asc'], ['priority', 'asc']]

# slice!(3)
# The number limit is not made
sort_criteria .slice!(3)
p sort_criteria 
=> [['priority', 'desc'], ['tracker', 'asc'], ['priority', 'asc'], ['subject', 'asc']]

I think it should be restricted to only three from the beginning like the case of "slice(0, 3)".
The attached file is a patch for fix.