🐛 [#4772] Add migration to set select dataType to string

because Select components did not have a dataType set, formio tries to cast it to other types if possible, which causes issues when submitting the data to the backend. For that reason we set the value to string to avoid this unwanted normalization

src/openforms/formio/migration_converters.py

@@ -208,6 +208,14 @@ def fix_multiple_empty_default_value(component: Component) -> bool:
     return False
 
 
+def set_datatype_string(component: Component):
+    # https://github.com/open-formulieren/open-forms/issues/4772
+    if component.get("dataType") != "string":
+        component["dataType"] = "string"
+        return True
+    return False
+
+
 def convert_simple_conditionals(configuration: JSONObject) -> bool:
     config_modified = False
 
@@ -350,6 +358,7 @@ def fix_empty_default_value(component: Component) -> bool:
     "select": {
         "set_openforms_datasrc": set_openforms_datasrc,
         "fix_multiple_empty_default_value": fix_multiple_empty_default_value,
+        "set_datatype_string": set_datatype_string,
     },
     "selectboxes": {"set_openforms_datasrc": set_openforms_datasrc},
     "currency": {

src/openforms/formio/typing/base.py

@@ -89,6 +89,7 @@ class Component(TypedDict):
     prefill: NotRequired[PrefillConfiguration]
     openForms: NotRequired[OpenFormsConfig]
     autocomplete: NotRequired[str]
+    dataType: NotRequired[str]
 
 
 class FormioConfiguration(TypedDict):

src/openforms/forms/migrations/0104_select_datatype_string.py

@@ -0,0 +1,16 @@
+# Generated by Django 4.2.16 on 2024-11-11 12:00
+
+from django.db import migrations
+
+from openforms.forms.migration_operations import ConvertComponentsOperation
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("forms", "0103_remove_formvariable_prefill_config_empty_or_complete_and_more"),
+    ]
+
+    operations = [
+        ConvertComponentsOperation("select", "set_datatype_string"),
+    ]