Use fieldset id instead of the fieldset title in Form when rendering the Field component

docs/source/upgrade-guide/index.md

@@ -218,6 +218,12 @@ The `.stories.mdx` extension is no longer supported.
 Although it is technically possible to keep the old version running, the script `volto-update-deps` will try to update to Storybook 8 every time you run it.
 ```
 
+### Form component passes down `id` of the current fieldset
+
+A bug where a fieldset's `title` contains spaces would cause the generated `id` to be invalid.
+This has been fixed by passing down the fieldset `id` instead of the `title`.
+If your tests rely on the old fieldset's generated `id` attribute for selecting fields, your tests could break, in which case you should amend them to use the updated fieldset's `id` instead.
+
 (volto-upgrade-guide-17.x.x)=
 
 ## Upgrading to Volto 17.x.x

packages/types/src/config/index.d.ts

@@ -17,8 +17,13 @@ export type ComponentsConfig = Record<
   { component: React.ComponentType }
 >;
 
-export type ExperimentalConfig = Record<string, unknown>;
+export interface ExperimentalConfig {
+  addBlockButton: {
+    enabled: boolean;
+  };
+}
 
+// This is a type because it's not supposed to be extendable
 export type ConfigData = {
   settings: SettingsConfig;
   blocks: BlocksConfig;

packages/volto/news/5921.bugfix

@@ -0,0 +1 @@
+Use fieldset id instead of the title in Form when rendering the Field component @sneridagh

packages/volto/src/components/manage/Form/Form.jsx

@@ -843,7 +843,7 @@ class Form extends Component {
                             {...schema.properties[field]}
                             id={field}
                             formData={formData}
-                            fieldSet={item.title.toLowerCase()}
+                            fieldSet={item.id}
                             focus={this.state.inFocus[field]}
                             value={formData?.[field]}
                             required={schema.required.indexOf(field) !== -1}