Nested models error: " undefined method `reverse' for nil:NilClass "

[kapellan]

Hello! I use nested models(think reason near this) and hard relations between them. When I try to create some model instance, i get such error in create action.

NoMethodError in AdvertsController#create
undefined method `reverse' for nil:NilClass

When gem is disabled - error disappears.

[furiabhavesh]

We are also facing same issue which does not come if we remove this gem.

[rubenrails]

Same error here.

[sudhirj]

That's a +1. The error happens here:

https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb#L14

Is QR setting binds to nil or something?

[jdelStrother]

I could be wrong, but I believe this is caused by Rails running its built-in EXPLAIN query, and QueryReviewer running an EXPLAIN on that. I'm not sure it's anything to do with nested models.

[EDIT: nevermind, I just reproduced it without an EXPLAIN. So much for that theory...]

[laurens]

same here

activerecord (3.2.11)

https://github.com/rails/rails/blob/v3.2.11/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb#L8

[laurens]

It works for me when going back to query_reviewer 0.1.6

[laurens]

No, unfortunately it does not. But this seems only to happen on POST requests.

[nesquena]

Hmm, anyone have a working theory for what's causing this? Unfortunately not using this project at the moment but still maintaining and happy to accept patches.

[jdelStrother]

Is everyone here using the mysql2 gem, and only seeing it on inserts?

[jdelStrother]

So... I can reproduce just by loading up Rails console, enabling query reviewer with :

Thread.current["queries"] = QueryReviewer::SqlQueryCollection.new; Thread.current["query_reviewer_enabled"] = true

and then performing an insert (eg Post.create()).

The problem seems to result from some state being stored in the mysqladapter itself:

ActiveRecord::ConnectionAdapters::DatabaseStatements#insert calls DatabaseStatements#to_sql(arel, binds). If you call arel.to_sql after this point, (like QueryReviewer does in sanitize_strings_and_numbers_from_sql), then you'll hit the undefined method 'reverse' for nil:NilClass error. If you call arel.to_sql before this point, it works fine.

I think the problem results from the BindSubstitution class, which once you've run DatabaseStatements#to_sql stashes an @block ivar which changes the behaviour of to_sql. My head is starting to hurt following all the arel visitor methods though, so I'm struggling to pin it down much further.

[eyaleizenberg]

This error is still happening on rails 3.2.13 with latest query reviewer.