Fix and add tests for writable violations due to surfaced changes at insertion

Author: green-david

lib/ecto/repo/schema.ex

@@ -452,7 +452,7 @@ defmodule Ecto.Repo.Schema do
     # On insert, we always merge the whole struct into the
     # changeset as changes, except the primary key if it is nil.
     changeset = put_repo_and_action(changeset, :insert, repo, tuplet)
-    changeset = Relation.surface_changes(changeset, struct, keep_fields ++ assocs)
+    changeset = Relation.surface_changes(changeset, struct, keep_fields ++ drop_fields ++ assocs)
     changeset = update_in(changeset.changes, &drop_non_writable_changes!(&1, drop_fields, schema, :insert))
 
     wrap_in_transaction(adapter, adapter_meta, opts, changeset, assocs, embeds, prepare, fn ->

test/ecto/repo_test.exs

@@ -2513,6 +2513,15 @@ defmodule Ecto.RepoTest do
                    end
     end
 
+    test "insert with surfaced changes on_writable_violation: :nothing saves changes for writable: :always/:insert and ignores changes for writable: :never" do
+      %MySchemaWritable{id: 1, always: 10, never: 11, insert: 12}
+      |> Ecto.Changeset.change(%{})
+      |> TestRepo.insert()
+
+      assert_received {:insert, %{fields: inserted_fields}}
+      assert Enum.sort(inserted_fields) == [always: 10, id: 1, insert: 12]
+    end
+
     test "insert with on_writable_violation: :nothing saves changes for writable: :always/:insert and ignores changes for writable: :never" do
       %MySchemaWritable{id: 1}
       |> Ecto.Changeset.change(%{always: 10, never: 11, insert: 12})
@@ -2522,6 +2531,19 @@ defmodule Ecto.RepoTest do
       assert Enum.sort(inserted_fields) == [always: 10, id: 1, insert: 12]
     end
 
+    test "insert with with surfaced changes and on_writable_violation: :warn saves changes for writable: :always/:insert, ignores changes for writable: :never, and logs a warning" do
+      log = capture_log(fn ->
+        %MySchemaWritableWarn{id: 1, always: 10, never: 11, insert: 12}
+        |> Ecto.Changeset.change(%{})
+        |> TestRepo.insert()
+
+        assert_received {:insert, %{fields: inserted_fields}}
+        assert Enum.sort(inserted_fields) == [always: 10, id: 1, insert: 12]
+      end)
+
+      assert log =~ "attempted to write to non-writable field :never during insert"
+    end
+
     test "insert with on_writable_violation: :warn saves changes for writable: :always/:insert, ignores changes for writable: :never, and logs a warning" do
       log = capture_log(fn ->
         %MySchemaWritableWarn{id: 1}
@@ -2535,6 +2557,21 @@ defmodule Ecto.RepoTest do
       assert log =~ "attempted to write to non-writable field :never during insert"
     end
 
+    test "insert with surfaced changes and on_writable_violation: :raise saves changes for writable: :always/:insert and raises for changes for writable: :never" do
+      assert_raise ArgumentError, "attempted to write to non-writable field :never during insert", fn ->
+        %MySchemaWritableRaise{id: 1, never: 10}
+        |> Ecto.Changeset.change(%{})
+        |> TestRepo.insert()
+      end
+
+      %MySchemaWritableRaise{id: 2, insert: 11, always: 12}
+      |> Ecto.Changeset.change(%{})
+      |> TestRepo.insert()
+
+      assert_received {:insert, %{fields: inserted_fields}}
+      assert Enum.sort(inserted_fields) == [always: 12, id: 2, insert: 11]
+    end
+
     test "insert with on_writable_violation: :raise saves changes for writable: :always/:insert and raises for changes for writable: :never" do
       assert_raise ArgumentError, "attempted to write to non-writable field :never during insert", fn ->
         %MySchemaWritableRaise{id: 1}