1
0
Fork 0
mirror of https://github.com/rails/rails.git synced 2022-11-09 12:12:34 -05:00

Correct through associations using scopes

The changes introduced to through associations in c80487eb were quite
interesting. Changing `relation.merge!(scope)` to `relation =
relation.merge(scope)` should in theory never cause any changes in
behavior. The subtle breakage led to a surprising conclusion.

The old code wasn't doing anything! Since `merge!` calls
`instance_exec` when given a proc, and most scopes will look something
like `has_many :foos, -> { where(foo: :bar) }`, if we're not capturing
the return value, it's a no-op. However, removing the `merge` causes
`unscope` to break.

While we're merging in the rest of the chain elsewhere, we were never
merging in `unscope` values, causing a breakage on associations where a
default scope was being unscoped in an association scope (yuk!). This is
subtly related to #20722, since it appears we were previously relying on
this mutability.

Fixes #20721.
Fixes #20727.
This commit is contained in:
Sean Griffin 2015-06-30 09:53:56 -07:00
parent f55c60f5ae
commit bc6ac8609c
4 changed files with 16 additions and 6 deletions

View file

@ -1,3 +1,11 @@
* Fix through associations using scopes having the scope merged multiple
times.
Fixes #20721.
Fixes #20727.
*Sean Griffin*
* `ActiveRecord::Base.dump_schema_after_migration` applies migration tasks
other than `db:migrate`. (eg. `db:rollback`, `db:migrate:dup`, ...)

View file

@ -149,6 +149,7 @@ module ActiveRecord
scope.where_clause += item.where_clause
scope.order_values |= item.order_values
scope.unscope!(*item.unscope_values)
end
reflection = reflection.next

View file

@ -15,12 +15,6 @@ module ActiveRecord
scope = super
reflection.chain.drop(1).each do |reflection|
relation = reflection.klass.all
reflection_scope = reflection.scope
if reflection_scope && reflection_scope.arity.zero?
relation = relation.merge(reflection_scope)
end
scope.merge!(
relation.except(:select, :create_with, :includes, :preload, :joins, :eager_load)
)

View file

@ -1158,4 +1158,11 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
post_through = organization.posts.build
assert_equal post_direct.author_id, post_through.author_id
end
def test_has_many_through_with_scope_that_should_not_be_fully_merged
Club.has_many :distinct_memberships, -> { distinct }, class_name: "Membership"
Club.has_many :special_favourites, through: :distinct_memberships, source: :member
assert_nil Club.new.special_favourites.distinct_value
end
end