Go through normal `where` logic when preloading associations

This will allow eager type casting to take place as needed. There
doesn't seem to be any particular reason that the `in` statement was
forced for single values, and the commit message where it was introduced
gives no context.

See
https://github.com/rails/rails/commit/d90b4e2615e8048fdeffc6dffe3246704adee01f

4 files changed, 4 insertions, 4 deletions

diff --git a/activerecord/test/cases/adapters/mysql2/explain_test.rb b/activerecord/test/cases/adapters/mysql2/explain_test.rb
index f67f21fab1..2b01d941b8 100644
--- a/activerecord/test/cases/adapters/mysql2/explain_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/explain_test.rb
@@ -18,7 +18,7 @@ module ActiveRecord
           explain = Developer.where(:id => 1).includes(:audit_logs).explain
           assert_match %(EXPLAIN for: SELECT `developers`.* FROM `developers` WHERE `developers`.`id` = 1), explain
           assert_match %r(developers |.* const), explain
-          assert_match %(EXPLAIN for: SELECT `audit_logs`.* FROM `audit_logs` WHERE `audit_logs`.`developer_id` IN (1)), explain
+          assert_match %(EXPLAIN for: SELECT `audit_logs`.* FROM `audit_logs` WHERE `audit_logs`.`developer_id` = 1), explain
           assert_match %r(audit_logs |.* ALL), explain
         end
       end
diff --git a/activerecord/test/cases/adapters/postgresql/explain_test.rb b/activerecord/test/cases/adapters/postgresql/explain_test.rb
index d2dd04b84b..6ffb4c9f33 100644
--- a/activerecord/test/cases/adapters/postgresql/explain_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/explain_test.rb
@@ -18,7 +18,7 @@ module ActiveRecord
           explain = Developer.where(:id => 1).includes(:audit_logs).explain
           assert_match %(QUERY PLAN), explain
           assert_match %(EXPLAIN for: SELECT "developers".* FROM "developers" WHERE "developers"."id" = $1), explain
-          assert_match %(EXPLAIN for: SELECT "audit_logs".* FROM "audit_logs" WHERE "audit_logs"."developer_id" IN (1)), explain
+          assert_match %(EXPLAIN for: SELECT "audit_logs".* FROM "audit_logs" WHERE "audit_logs"."developer_id" = 1), explain
         end
       end
     end
diff --git a/activerecord/test/cases/adapters/sqlite3/explain_test.rb b/activerecord/test/cases/adapters/sqlite3/explain_test.rb
index de6e35ef57..7d66c44798 100644
--- a/activerecord/test/cases/adapters/sqlite3/explain_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/explain_test.rb
@@ -18,7 +18,7 @@ module ActiveRecord
           explain = Developer.where(:id => 1).includes(:audit_logs).explain
           assert_match %(EXPLAIN for: SELECT "developers".* FROM "developers" WHERE "developers"."id" = ?), explain
           assert_match(/(SEARCH )?TABLE developers USING (INTEGER )?PRIMARY KEY/, explain)
-          assert_match %(EXPLAIN for: SELECT "audit_logs".* FROM "audit_logs" WHERE "audit_logs"."developer_id" IN (1)), explain
+          assert_match %(EXPLAIN for: SELECT "audit_logs".* FROM "audit_logs" WHERE "audit_logs"."developer_id" = 1), explain
           assert_match(/(SCAN )?TABLE audit_logs/, explain)
         end
       end
diff --git a/activerecord/test/cases/inheritance_test.rb b/activerecord/test/cases/inheritance_test.rb
index 0338669016..fe6323ab02 100644
--- a/activerecord/test/cases/inheritance_test.rb
+++ b/activerecord/test/cases/inheritance_test.rb
@@ -304,7 +304,7 @@ class InheritanceTest < ActiveRecord::TestCase
 
   def test_eager_load_belongs_to_primary_key_quoting
     con = Account.connection
-    assert_sql(/#{con.quote_table_name('companies')}.#{con.quote_column_name('id')} IN \(1\)/) do
+    assert_sql(/#{con.quote_table_name('companies')}.#{con.quote_column_name('id')} = 1/) do
       Account.all.merge!(:includes => :firm).find(1)
     end
   end