From 22ca710f20c3c656811df006cbf1f4dbc359f7a6 Mon Sep 17 00:00:00 2001
From: Ryuta Kamizono <kamipo@gmail.com>
Date: Mon, 21 Nov 2016 05:01:41 +0900
Subject: [PATCH 1/2] Fix unscope with subquery

Currently cannot unscope subquery properly.
This commit fixes the issue.

Fixes #26323.
---
 .../active_record/relation/where_clause.rb    | 29 ++++++++++++-------
 activerecord/test/cases/relations_test.rb     | 12 ++++++++
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/activerecord/lib/active_record/relation/where_clause.rb b/activerecord/lib/active_record/relation/where_clause.rb
index 402f8acfd1..e862a9048e 100644
--- a/activerecord/lib/active_record/relation/where_clause.rb
+++ b/activerecord/lib/active_record/relation/where_clause.rb
@@ -25,10 +25,7 @@ def merge(other)
       end
 
       def except(*columns)
-        WhereClause.new(
-          predicates_except(columns),
-          binds_except(columns),
-        )
+        WhereClause.new(*except_predicates_and_binds(columns))
       end
 
       def or(other)
@@ -132,20 +129,32 @@ def invert_predicate(node)
           end
         end
 
-        def predicates_except(columns)
-          predicates.reject do |node|
+        def except_predicates_and_binds(columns)
+          except_binds = []
+          binds_index = 0
+
+          predicates = self.predicates.reject do |node|
             case node
             when Arel::Nodes::Between, Arel::Nodes::In, Arel::Nodes::NotIn, Arel::Nodes::Equality, Arel::Nodes::NotEqual, Arel::Nodes::LessThan, Arel::Nodes::LessThanOrEqual, Arel::Nodes::GreaterThan, Arel::Nodes::GreaterThanOrEqual
+              binds_contains = node.grep(Arel::Nodes::BindParam).size
               subrelation = (node.left.kind_of?(Arel::Attributes::Attribute) ? node.left : node.right)
               columns.include?(subrelation.name.to_s)
+            end.tap do |except|
+              if except && binds_contains > 0
+                (binds_index...(binds_index + binds_contains)).each do |i|
+                  except_binds[i] = true
+                end
+
+                binds_index += binds_contains
+              end
             end
           end
-        end
 
-        def binds_except(columns)
-          binds.reject do |attr|
-            columns.include?(attr.name)
+          binds = self.binds.reject.with_index do |_, i|
+            except_binds[i]
           end
+
+          [predicates, binds]
         end
 
         def predicates_with_wrapped_sql_literals
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 96833ad428..716ace9686 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -1962,6 +1962,18 @@ def test_presence
     assert !Post.all.respond_to?(:by_lifo)
   end
 
+  def test_unscope_with_subquery
+    p1 = Post.where(id: 1)
+    p2 = Post.where(id: 2)
+
+    assert_not_equal p1, p2
+
+    comments = Comment.where(post: p1).unscope(where: :post_id).where(post: p2)
+
+    assert_not_equal p1.first.comments, comments
+    assert_equal p2.first.comments, comments
+  end
+
   def test_unscope_removes_binds
     left = Post.where(id: Arel::Nodes::BindParam.new)
     column = Post.columns_hash["id"]

From bbf1f152644177774710c52a230813e7d06935df Mon Sep 17 00:00:00 2001
From: Ryuta Kamizono <kamipo@gmail.com>
Date: Mon, 13 Feb 2017 12:44:37 +0900
Subject: [PATCH 2/2] Refactor `except_predicates_and_binds` to avoid `tap`

---
 .../active_record/relation/where_clause.rb    | 27 ++++++++++---------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/activerecord/lib/active_record/relation/where_clause.rb b/activerecord/lib/active_record/relation/where_clause.rb
index e862a9048e..e550fcf7ae 100644
--- a/activerecord/lib/active_record/relation/where_clause.rb
+++ b/activerecord/lib/active_record/relation/where_clause.rb
@@ -134,20 +134,23 @@ def except_predicates_and_binds(columns)
           binds_index = 0
 
           predicates = self.predicates.reject do |node|
-            case node
-            when Arel::Nodes::Between, Arel::Nodes::In, Arel::Nodes::NotIn, Arel::Nodes::Equality, Arel::Nodes::NotEqual, Arel::Nodes::LessThan, Arel::Nodes::LessThanOrEqual, Arel::Nodes::GreaterThan, Arel::Nodes::GreaterThanOrEqual
-              binds_contains = node.grep(Arel::Nodes::BindParam).size
-              subrelation = (node.left.kind_of?(Arel::Attributes::Attribute) ? node.left : node.right)
-              columns.include?(subrelation.name.to_s)
-            end.tap do |except|
-              if except && binds_contains > 0
-                (binds_index...(binds_index + binds_contains)).each do |i|
-                  except_binds[i] = true
-                end
-
-                binds_index += binds_contains
+            except = \
+              case node
+              when Arel::Nodes::Between, Arel::Nodes::In, Arel::Nodes::NotIn, Arel::Nodes::Equality, Arel::Nodes::NotEqual, Arel::Nodes::LessThan, Arel::Nodes::LessThanOrEqual, Arel::Nodes::GreaterThan, Arel::Nodes::GreaterThanOrEqual
+                binds_contains = node.grep(Arel::Nodes::BindParam).size
+                subrelation = (node.left.kind_of?(Arel::Attributes::Attribute) ? node.left : node.right)
+                columns.include?(subrelation.name.to_s)
               end
+
+            if except && binds_contains > 0
+              (binds_index...(binds_index + binds_contains)).each do |i|
+                except_binds[i] = true
+              end
+
+              binds_index += binds_contains
             end
+
+            except
           end
 
           binds = self.binds.reject.with_index do |_, i|