feat: type not editable

test/membership/custom_field_validation_test.exs

@@ -8,6 +8,7 @@ defmodule Mv.Membership.CustomFieldValidationTest do
   - Description length validation (max 500 characters)
   - Description trimming
   - Required vs optional fields
+  - Value type immutability (cannot be changed after creation)
   """
   use Mv.DataCase, async: true
 
@@ -207,4 +208,101 @@ defmodule Mv.Membership.CustomFieldValidationTest do
       assert [%{field: :value_type}] = changeset.errors
     end
   end
+
+  describe "value_type immutability" do
+    test "rejects attempt to change value_type after creation", %{actor: actor} do
+      # Create custom field with value_type :string
+      {:ok, custom_field} =
+        CustomField
+        |> Ash.Changeset.for_create(:create, %{
+          name: "test_field",
+          value_type: :string
+        })
+        |> Ash.create(actor: actor)
+
+      original_value_type = custom_field.value_type
+      assert original_value_type == :string
+
+      # Attempt to update value_type to :integer
+      assert {:error, %Ash.Error.Invalid{} = error} =
+               custom_field
+               |> Ash.Changeset.for_update(:update, %{
+                 value_type: :integer
+               })
+               |> Ash.update(actor: actor)
+
+      # Verify error message contains expected text
+      error_message = Exception.message(error)
+      assert error_message =~ "cannot be changed" or error_message =~ "value_type"
+
+      # Reload and verify value_type remained unchanged
+      reloaded = Ash.get!(CustomField, custom_field.id, actor: actor)
+      assert reloaded.value_type == original_value_type
+      assert reloaded.value_type == :string
+    end
+
+    test "allows updating other fields while value_type remains unchanged", %{actor: actor} do
+      # Create custom field with value_type :string
+      {:ok, custom_field} =
+        CustomField
+        |> Ash.Changeset.for_create(:create, %{
+          name: "test_field",
+          value_type: :string,
+          description: "Original description"
+        })
+        |> Ash.create(actor: actor)
+
+      original_value_type = custom_field.value_type
+      assert original_value_type == :string
+
+      # Update other fields (name, description) without touching value_type
+      {:ok, updated_custom_field} =
+        custom_field
+        |> Ash.Changeset.for_update(:update, %{
+          name: "updated_name",
+          description: "Updated description"
+        })
+        |> Ash.update(actor: actor)
+
+      # Verify value_type remained unchanged
+      assert updated_custom_field.value_type == original_value_type
+      assert updated_custom_field.value_type == :string
+      # Verify other fields were updated
+      assert updated_custom_field.name == "updated_name"
+      assert updated_custom_field.description == "Updated description"
+    end
+
+    test "rejects value_type change even when other fields are updated", %{actor: actor} do
+      # Create custom field with value_type :boolean
+      {:ok, custom_field} =
+        CustomField
+        |> Ash.Changeset.for_create(:create, %{
+          name: "test_field",
+          value_type: :boolean
+        })
+        |> Ash.create(actor: actor)
+
+      original_value_type = custom_field.value_type
+      assert original_value_type == :boolean
+
+      # Attempt to update both name and value_type
+      assert {:error, %Ash.Error.Invalid{} = error} =
+               custom_field
+               |> Ash.Changeset.for_update(:update, %{
+                 name: "updated_name",
+                 value_type: :date
+               })
+               |> Ash.update(actor: actor)
+
+      # Verify error message
+      error_message = Exception.message(error)
+      assert error_message =~ "cannot be changed" or error_message =~ "value_type"
+
+      # Reload and verify value_type remained unchanged, but name was not updated either
+      reloaded = Ash.get!(CustomField, custom_field.id, actor: actor)
+      assert reloaded.value_type == original_value_type
+      assert reloaded.value_type == :boolean
+      assert reloaded.name == "test_field"
+    end
+  end
 end