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#2740 ✓stale
Matt Hanlon

Find conditions get clobbered by nested scopes

Reported by Matt Hanlon | May 29th, 2009 @ 09:52 PM | in 3.x

In ActiveRecord 2.3.2, nested scopes (named or dynamic) that have conditions hashes with common keys get overwritten by the final scope. For instance suppose there is a Widget model with id and name fields. Then

Widget.scoped_by_id([1,2,3]).scoped_by_name('foo').all

will return the widgets where the id is in [1,2,3] AND the name is 'foo'. One would then expect that

Widget.scoped_by_id([1,2,3]).scoped_by_id([3,4,5]).all

would return only the widget with id=3 (using AND), but in fact the id condition of the second scope clobbers the first and we get any widgets matching [3,4,5].

This behavior is a change from previous versions of ActiveRecord and seems to be an intentional result of this checkin:

http://github.com/rails/rails/commit/fe6ffce51dc16285094be49244b265...

To my mind this breaks the semantics of a scope for finding, which should be a way to restrict results and should be arbitrarily chainable.

Comments and changes to this ticket

  • Matt Hanlon

    Matt Hanlon May 29th, 2009 @ 09:57 PM

    As background, I came across this issue while upgrading a 2.1 rails app that uses nested find scopes to implement some user access control. Basically it uses named scopes like

    Asset.filter_by_user_access(some_user).filter_by_search_terms(some_term)

    In this case, the search scope clobbered the access scope since they both relied on some of the same fields.

  • Joe Goldberg

    Joe Goldberg May 29th, 2009 @ 10:18 PM

    I'm having this problem too. How can we get http://github.com/lifo to see this ticket so he can comment on the change?

  • Matt Hanlon

    Matt Hanlon June 22nd, 2009 @ 07:54 PM

    • Tag set to “2.3.2, activerecord, condition, find, named_scope, s”
  • Matt Hanlon

    Matt Hanlon June 22nd, 2009 @ 07:54 PM

    • Tag changed from “2.3.2, activerecord, condition, find, named_scope, s” to “2.3.2, activerecord, condition, find, named_scope”
  • Jeremy Kemper

    Jeremy Kemper May 4th, 2010 @ 06:48 PM

    • Milestone changed from “2.x” to “3.x”
  • Rohit Arondekar

    Rohit Arondekar October 9th, 2010 @ 04:06 AM

    • State changed from “new” to “stale”
    • Importance changed from “” to “”

    Marking ticket as stale. If this is still an issue please leave a comment with suggested changes, creating a patch with tests, rebasing an existing patch or just confirming the issue on a latest release or master/branches.

  • bingbing

    bingbing March 26th, 2011 @ 02:13 AM

  • Henning

    Henning March 31st, 2011 @ 04:45 PM

    This issue seems to be fixed in Rails 3.0.5, but it is still a problem with older version of Rails 3 and every version of Rails 2. A long writeup on the issue can be found here: http://makandra.com/notes/740-know-the-side-effects-of-using-hashes...

    This should be fixed for Rails 2 because every application that uses scopes to restrict user access might be broken.

    I could provide a patch that fixes this for the 2-3-stable branch. Given that Rails 3 is the hot new thing now, would my fix still be considered for a future release?

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