This line:
author = Mongoid::QueryCache.cache

causes error: undefined method `select_server' for nil:NilClass

backtrace:

vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/query_cache.rb:225:in `each'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/contextual/mongo.rb:132:in `each'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/contextual.rb:20:in `each'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/criteria/findable.rb:108:in `entries'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/criteria/findable.rb:108:in `from_database'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/criteria/findable.rb:76:in `multiple_from_db'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/criteria/findable.rb:20:in `execute_or_raise'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/criteria/findable.rb:41:in `find'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/findable.rb:94:in `find'
app/views/svetovanje/novice.html.erb:15:in `block (3 levels) in _app_views_svetovanjenovice_html_erb__2280375005956261036_69126640'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/query_cache.rb:69:in `cache'
app/views/svetovanje/novice.html.erb:15:in `block (2 levels) in _app_views_svetovanjenovice_html_erb__2280375005956261036_69126640'
vendor/ruby/2.4.0/gems/actionview-5.1.4/lib/action_view/helpers/capture_helper.rb:39:in `block in capture'
vendor/ruby/2.4.0/gems/actionview-5.1.4/lib/action_view/helpers/capture_helper.rb:203:in `with_output_buffer'
vendor/ruby/2.4.0/gems/actionview-5.1.4/lib/action_view/helpers/capture_helper.rb:39:in `capture'
vendor/ruby/2.4.0/gems/actionview-5.1.4/lib/action_view/helpers/tag_helper.rb:272:in `content_tag'
vendor/ruby/2.4.0/gems/actionview-5.1.4/lib/action_view/helpers/url_helper.rb:198:in `link_to'
app/views/svetovanje/novice.html.erb:12:in `block in _app_views_svetovanjenovice_html_erb__2280375005956261036_69126640'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/contextual/mongo.rb:696:in `yield_document'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/contextual/mongo.rb:133:in `block in each'
vendor/ruby/2.4.0/gems/mongo-2.5.0/lib/mongo/collection/view/iterable.rb:46:in `block in each'
vendor/ruby/2.4.0/gems/mongo-2.5.0/lib/mongo/cursor.rb:117:in `block in each'
vendor/ruby/2.4.0/gems/mongo-2.5.0/lib/mongo/cursor.rb:117:in `each'
vendor/ruby/2.4.0/gems/mongo-2.5.0/lib/mongo/cursor.rb:117:in `each'
vendor/ruby/2.4.0/gems/mongo-2.5.0/lib/mongo/collection/view/iterable.rb:45:in `each'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/query_cache.rb:222:in `each'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/contextual/mongo.rb:132:in `each'
vendor/ruby/2.4.0/gems/mongoid-6.2.1/lib/mongoid/contextual.rb:20:in `each'

etc .....

It happens only with mongo 2.5.0. driver. Reverting to mongo 2.4.3. version makes problem disapear.

by
Damjan Rems