Change `having_values` to use the `WhereClause` class

This fixed an issue where `having` can only be called after the last
call to `where`, because it messes with the same `bind_values` array.
With this change, the two can be called as many times as needed, in any
order, and the final query will be correct. However, once something
assigns `bind_values`, that stops. This is because we have to move all
of the bind values from the having clause over to the where clause since
we can't differentiate the two, and assignment was likely in the form
of:

`relation.bind_values += other.bind_values`

This will go away once we remove all places that are assigning
`bind_values`, which is next on the list.

While this fixes a bug that was present in at least 4.2 (more likely
present going back as far as 3.0, becoming more likely in 4.1 and later
as we switched to prepared statements in more cases), I don't think this
can be easily backported. The internal changes to `Relation` are
non-trivial, anything that involves modifying the `bind_values` array
would need to change, and I'm not confident that we have sufficient test
coverage of all of those locations (when `having` was called with a hash
that could generate bind values).

[Sean Griffin & anthonynavarre]

1 files changed, 18 insertions, 2 deletions

diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index d272b9b929..e0e04a0891 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -1468,10 +1468,26 @@ class RelationTest < ActiveRecord::TestCase
 
   def test_doesnt_add_having_values_if_options_are_blank
     scope = Post.having('')
-    assert_equal [], scope.having_values
+    assert scope.having_clause.empty?
 
     scope = Post.having([])
-    assert_equal [], scope.having_values
+    assert scope.having_clause.empty?
+  end
+
+  def test_having_with_binds_for_both_where_and_having
+    post = Post.first
+    having_then_where = Post.having(id: post.id).where(title: post.title).group(:title)
+    where_then_having = Post.where(title: post.title).having(id: post.id).group(:title)
+
+    assert_equal [post], having_then_where
+    assert_equal [post], where_then_having
+  end
+
+  def test_multiple_where_and_having_clauses
+    post = Post.first
+    having_then_where = Post.having(id: post.id).where(title: post.title).having(id: post.id).where(title: post.title).group(:title)
+
+    assert_equal [post], having_then_where
   end
 
   def test_references_triggers_eager_loading