find_byの実行中にメソッドエラーが発生しません。これはレールのバグですか？

Question

私は公式にアイデアがありません：Pこれはレール問題になるかもしれないと思っていますが、私が間違いを犯した人だと思うほとんどの時間：私はこの質問をしましたしかし別の方法で）StackOverflowで2回、私は正しい答えを得られなかった。だから私は新しいアプローチを試みている。

この行があります：

DiscoveredLocation.find_all_by_user_id(user.id, :include => [:boss_kills]) 

getLocationNextBossesは上記のみの行を実行します。

このエラーメッセージは何が作成される可能性がありますか？これはfind内のレール実装の一部であるようです。どう思いますか ？ （user.idは正しいbtwです）。

NoMethodError in BossesController#index 

You have a nil object when you didn't expect it! 
You might have expected an instance of Array. 
The error occurred while evaluating nil.each 

RAILS_ROOT: /Users/hthought/rails/bbg 
Application Trace | Framework Trace | Full Trace 

/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:125:in `add_preloaded_records_to_collection' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:243:in `preload_has_many_association' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:241:in `each' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:241:in `preload_has_many_association' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:120:in `send' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:120:in `preload_one_association' 
/opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/ordered_hash.rb:97:in `each' 
/opt/local/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/ordered_hash.rb:97:in `each' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:114:in `preload_one_association' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:91:in `preload_associations' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:90:in `preload_associations' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:90:in `each' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/association_preload.rb:90:in `preload_associations' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:1550:in `find_every' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:615:in `find' 
/opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.5/lib/active_record/base.rb:1900:in `find_all_by_user_id' 
/Users/hthought/rails/bbg/app/models/boss_kill.rb:12:in `getLocationNextBosses' 
/Users/hthought/rails/bbg/app/controllers/bosses_controller.rb:8:in `index' 

development.logも示しています

[4;35;1mBossKill Load (0.3ms)[0m [0mSELECT `boss_kills`.* FROM `boss_kills` WHERE (`boss_kills`.monster_id IN (695794181,732497461)) [0m 
    [4;36;1mBossKill Columns (11.9ms)[0m [0;1mSHOW FIELDS FROM `boss_kills`[0m 

NoMethodError (You have a nil object when you didn't expect it! 
You might have expected an instance of Array. 
The error occurred while evaluating nil.each): 
    app/models/boss_kill.rb:12:in `getLocationNextBosses' 
    app/controllers/bosses_controller.rb:8:in `index' 
    /opt/local/lib/ruby/1.8/webrick/httpserver.rb:104:in `service' 
    /opt/local/lib/ruby/1.8/webrick/httpserver.rb:65:in `run' 
    /opt/local/lib/ruby/1.8/webrick/server.rb:173:in `start_thread' 
    /opt/local/lib/ruby/1.8/webrick/server.rb:162:in `start' 
    /opt/local/lib/ruby/1.8/webrick/server.rb:162:in `start_thread' 
    /opt/local/lib/ruby/1.8/webrick/server.rb:95:in `start' 
    /opt/local/lib/ruby/1.8/webrick/server.rb:92:in `each' 
    /opt/local/lib/ruby/1.8/webrick/server.rb:92:in `start' 
    /opt/local/lib/ruby/1.8/webrick/server.rb:23:in `start' 
    /opt/local/lib/ruby/1.8/webrick/server.rb:82:in `start' 

Rendered rescues/_trace (114.2ms) 
Rendered rescues/_request_and_response (0.8ms) 
Rendering rescues/layout (internal_server_error) 

Answer 1

これはRailsのバグですか？

非常にありそうもありません。

このエラーメッセージはどのような原因で発生する可能性がありますか？

もう少しコードを見ずに分かりにくいです。私はUserモデル、BossKillモデル、BossesController#indexアクションを開始して投稿することをお勧めします。