From a60a20bb7faae4d0758676b865f625275c500e4e Mon Sep 17 00:00:00 2001
From: bogdanvlviv <bogdanvlviv@gmail.com>
Date: Mon, 22 Aug 2016 21:16:08 +0300
Subject: [PATCH] Added ability update locking_column value

---
 activerecord/CHANGELOG.md                     |  5 ++
 .../lib/active_record/locking/optimistic.rb   | 14 ++--
 activerecord/test/cases/dirty_test.rb         |  2 +-
 activerecord/test/cases/locking_test.rb       | 76 +++++++++++++++++++
 4 files changed, 90 insertions(+), 7 deletions(-)

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index db9c394a65..f847c71420 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Optimistic locking: Added ability update locking_column value.
+    Ignore optimistic locking if update with new locking_column value.
+
+    *bogdanvlviv*
+
 *   Fixed: Optimistic locking does not work well with null in the database.
 
     Fixes #26024
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index fa9e789b24..d39b7181f4 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -78,17 +78,19 @@ module ActiveRecord
 
         def _update_record(attribute_names = self.attribute_names) #:nodoc:
           return super unless locking_enabled?
-          return 0 if attribute_names.empty?
 
           lock_col = self.class.locking_column
-          previous_lock_value = read_attribute_before_type_cast(lock_col)
 
-          increment_lock
-
-          attribute_names += [lock_col]
-          attribute_names.uniq!
+          return super if attribute_names.include?(lock_col)
+          return 0 if attribute_names.empty?
 
           begin
+            previous_lock_value = read_attribute_before_type_cast(lock_col)
+
+            increment_lock
+
+            attribute_names.push(lock_col)
+
             relation = self.class.unscoped
 
             affected_rows = relation.where(
diff --git a/activerecord/test/cases/dirty_test.rb b/activerecord/test/cases/dirty_test.rb
index 09bd00291d..3bd8475bb0 100644
--- a/activerecord/test/cases/dirty_test.rb
+++ b/activerecord/test/cases/dirty_test.rb
@@ -341,7 +341,7 @@ class DirtyTest < ActiveRecord::TestCase
 
   def test_partial_update_with_optimistic_locking
     person = Person.new(first_name: "foo")
-    old_lock_version = 1
+    old_lock_version = person.lock_version
 
     with_partial_writes Person, false do
       assert_queries(2) { 2.times { person.save! } }
diff --git a/activerecord/test/cases/locking_test.rb b/activerecord/test/cases/locking_test.rb
index 8b6a969c9e..0579df0a07 100644
--- a/activerecord/test/cases/locking_test.rb
+++ b/activerecord/test/cases/locking_test.rb
@@ -247,6 +247,44 @@ class OptimisticLockingTest < ActiveRecord::TestCase
     assert_equal "new title2", t2.title
   end
 
+  def test_lock_without_default_should_update_with_lock_col
+    t1 = LockWithoutDefault.create(title: "title1", lock_version: 6)
+
+    assert_equal 6, t1.lock_version
+
+    t1.update(lock_version: 0)
+    t1.reload
+
+    assert_equal 0, t1.lock_version
+  end
+
+  def test_lock_without_default_queries_count
+    t1 = LockWithoutDefault.create(title: "title1")
+
+    assert_equal "title1", t1.title
+    assert_equal 0, t1.lock_version
+
+    assert_queries(1) { t1.update(title: "title2") }
+
+    t1.reload
+    assert_equal "title2", t1.title
+    assert_equal 1, t1.lock_version
+
+    assert_queries(1) { t1.update(title: "title3", lock_version: 6) }
+
+    t1.reload
+    assert_equal "title3", t1.title
+    assert_equal 6, t1.lock_version
+
+    t2 = LockWithoutDefault.new(title: "title1")
+
+    assert_queries(1) { t2.save! }
+
+    t2.reload
+    assert_equal "title1", t2.title
+    assert_equal 0, t2.lock_version
+  end
+
   def test_lock_with_custom_column_without_default_sets_version_to_zero
     t1 = LockWithCustomColumnWithoutDefault.new
 
@@ -283,6 +321,44 @@ class OptimisticLockingTest < ActiveRecord::TestCase
     assert_equal "new title2", t2.title
   end
 
+  def test_lock_with_custom_column_without_default_should_update_with_lock_col
+    t1 = LockWithCustomColumnWithoutDefault.create(title: "title1", custom_lock_version: 6)
+
+    assert_equal 6, t1.custom_lock_version
+
+    t1.update(custom_lock_version: 0)
+    t1.reload
+
+    assert_equal 0, t1.custom_lock_version
+  end
+
+  def test_lock_with_custom_column_without_default_queries_count
+    t1 = LockWithCustomColumnWithoutDefault.create(title: "title1")
+
+    assert_equal "title1", t1.title
+    assert_equal 0, t1.custom_lock_version
+
+    assert_queries(1) { t1.update(title: "title2") }
+
+    t1.reload
+    assert_equal "title2", t1.title
+    assert_equal 1, t1.custom_lock_version
+
+    assert_queries(1) { t1.update(title: "title3", custom_lock_version: 6) }
+
+    t1.reload
+    assert_equal "title3", t1.title
+    assert_equal 6, t1.custom_lock_version
+
+    t2 = LockWithCustomColumnWithoutDefault.new(title: "title1")
+
+    assert_queries(1) { t2.save! }
+
+    t2.reload
+    assert_equal "title1", t2.title
+    assert_equal 0, t2.custom_lock_version
+  end
+
   def test_readonly_attributes
     assert_equal Set.new([ "name" ]), ReadonlyNameShip.readonly_attributes