Arel: Implemented DB-aware NULL-safe comparison (#34451)

* Arel: Implemented DB-aware NULL-safe comparison

* Fixed where clause inversion for NULL-safe comparison

* Renaming "null_safe_eq" to "is_not_distinct_from", "null_safe_not_eq" to "is_distinct_from"

[Dmytro Shteflyuk + Rafael Mendonça França]

1 files changed, 39 insertions, 0 deletions

diff --git a/activerecord/test/cases/arel/visitors/postgres_test.rb b/activerecord/test/cases/arel/visitors/postgres_test.rb
index f7f2c76b6f..0f9efb20b4 100644
--- a/activerecord/test/cases/arel/visitors/postgres_test.rb
+++ b/activerecord/test/cases/arel/visitors/postgres_test.rb
@@ -276,6 +276,45 @@ module Arel
           }
         end
       end
+
+      describe "Nodes::IsNotDistinctFrom" do
+        it "should construct a valid generic SQL statement" do
+          test = Table.new(:users)[:name].is_not_distinct_from "Aaron Patterson"
+          compile(test).must_be_like %{
+            "users"."name" IS NOT DISTINCT FROM 'Aaron Patterson'
+          }
+        end
+
+        it "should handle column names on both sides" do
+          test = Table.new(:users)[:first_name].is_not_distinct_from Table.new(:users)[:last_name]
+          compile(test).must_be_like %{
+            "users"."first_name" IS NOT DISTINCT FROM "users"."last_name"
+          }
+        end
+
+        it "should handle nil" do
+          @table = Table.new(:users)
+          val = Nodes.build_quoted(nil, @table[:active])
+          sql = compile Nodes::IsNotDistinctFrom.new(@table[:name], val)
+          sql.must_be_like %{ "users"."name" IS NOT DISTINCT FROM NULL }
+        end
+      end
+
+      describe "Nodes::IsDistinctFrom" do
+        it "should handle column names on both sides" do
+          test = Table.new(:users)[:first_name].is_distinct_from Table.new(:users)[:last_name]
+          compile(test).must_be_like %{
+            "users"."first_name" IS DISTINCT FROM "users"."last_name"
+          }
+        end
+
+        it "should handle nil" do
+          @table = Table.new(:users)
+          val = Nodes.build_quoted(nil, @table[:active])
+          sql = compile Nodes::IsDistinctFrom.new(@table[:name], val)
+          sql.must_be_like %{ "users"."name" IS DISTINCT FROM NULL }
+        end
+      end
     end
   end
 end