Merge pull request rails#54790 from andyundso/upserts-only-last-update

Test if `insert_all` / `upsert_all` apply correct values when given duplicate identifiers in same call

Author: byroot

activerecord/test/cases/insert_all_test.rb

@@ -185,6 +185,16 @@ def test_insert_all_with_skip_duplicates_and_autonumber_id_given
     end
   end
 
+  def test_insert_all_only_applies_last_value_when_given_duplicate_identifiers
+    skip unless supports_insert_on_duplicate_skip?
+
+    Book.insert_all [
+      { id: 111, name: "expected_new_name" },
+      { id: 111, name: "unexpected_new_name" }
+    ]
+    assert_equal "expected_new_name", Book.find(111).name
+  end
+
   def test_skip_duplicates_strategy_does_not_secretly_upsert
     skip unless supports_insert_on_duplicate_skip?
 
@@ -399,6 +409,18 @@ def test_upsert_all_updates_existing_record_by_primary_key
     assert_equal "New edition", Book.find(1).name
   end
 
+  def test_upsert_all_only_applies_last_value_when_given_duplicate_identifiers
+    skip unless supports_insert_on_duplicate_update? && !current_adapter?(:PostgreSQLAdapter)
+
+    Book.create!(id: 112, name: "original_name")
+
+    Book.upsert_all [
+      { id: 112, name: "unexpected_new_name" },
+      { id: 112, name: "expected_new_name" }
+    ]
+    assert_equal "expected_new_name", Book.find(112).name
+  end
+
   def test_upsert_all_does_notupdates_existing_record_by_when_there_is_no_key
     skip unless supports_insert_on_duplicate_update? && !supports_insert_conflict_target?