Rename current_build_id sort option to current_build

lib/travis/api/v3/queries/repositories.rb

@@ -3,7 +3,14 @@ module Travis::API::V3
     params :active, :private, :starred, prefix: :repository
     sortable_by :id, :github_id, :owner_name, :name, active: sort_condition(:active),
                 :'default_branch.last_build' => 'builds.started_at',
-                :current_build_id => "repositories.current_build_id %{order} NULLS LAST"
+                :current_build => "repositories.current_build_id %{order} NULLS LAST"
+
+    # this is a hack for a bug in AR that generates invalid query when it tries
+    # to include `current_build` and join it at the same time. We don't actually
+    # need the join, but it will be automatically added, because `current_build`
+    # is an association. This prevents adding the join. We will probably be able
+    # to remove it once we move to newer AR versions
+    prevent_sortable_join :current_build
 
     def for_member(user, **options)
       all(user: user, **options).joins(:users).where(users: user_condition(user), invalidated_at: nil)

lib/travis/api/v3/query.rb

@@ -70,6 +70,15 @@ module Travis::API::V3
       mapping.each { |key, value| sort_by[key.to_s]   = prefix(value) }
     end
 
+    def self.prevent_sortable_join(*fields)
+      dont_join.push(*fields.map(&:to_s))
+    end
+
+    @dont_join = []
+    def self.dont_join
+      @dont_join ||= superclass.dont_join.dup
+    end
+
     def self.sort_condition(condition)
       if condition.is_a? Hash
         condition = condition.map { |e| e.map { |v| prefix(v) }.join(" = ".freeze) }.join(" and ".freeze)
@@ -172,6 +181,7 @@ module Travis::API::V3
     end
 
     def sort_join?(collection, field)
+      return if self.class.dont_join.include?(field)
       !collection.reflect_on_association(field.to_sym).nil?
     end