>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3601415. --> Reported by: [pfrenssen](https://www.drupal.org/user/382067) Related to !96 >>> <h3 id="summary-problem-motivation">Problem/Motivation</h3> <p>The generated <code>WebformElementMarkupBase</code> interface bundles two unrelated fields: <code>markup</code> (the element's authored HTML) and <code>displayOn</code> (whether the element renders on the form, the submission view, both, or nowhere). <code>WebformSchemaBuilder</code> assigns this interface to every element whose plugin extends <code>WebformMarkupBase</code>.</p> <p>Several of those elements are display-only and never populate <code>#markup</code> &mdash; they carry their content elsewhere or have none at all. They are pulled into the interface only for <code>displayOn</code>, yet they also inherit a <code>markup</code> field that is structurally always <code>null</code>:</p> <ul> <li><code>WebformElementWebformMessage</code> &mdash; body lives in <code>#message_message</code>, exposed as <code>messageBody</code>.</li> <li><code>WebformElementLabel</code></li> <li><code>WebformElementWebformMore</code></li> <li><code>WebformElementView</code> &mdash; identified by <code>name</code> / <code>displayId</code> / <code>arguments</code>.</li> </ul> <p>A frontend introspecting the schema sees a <code>markup</code> field on these types and cannot tell from the schema that it will only ever return <code>null</code>. The conflation also misrepresents the domain: in Webform itself, "displays on" is a separate <code>WebformElementDisplayOnInterface</code>, while markup content is the concern of <code>WebformMarkupBase</code>. The GraphQL schema flattened the two into one interface.</p> <h4 id="summary-steps-reproduce">Steps to reproduce</h4> <p>Query <code>markup</code> on a <code>webform_message</code> (or <code>label</code> / <code>webform_more</code>) element via <code>form { elements { ... on WebformElementMarkupBase { markup } } }</code>. The field resolves to <code>null</code> for every such element, with no schema signal that it must.</p> <h3 id="summary-proposed-resolution">Proposed resolution</h3> <p>Separate the two concerns, mirroring Webform's own split:</p> <ul> <li>Add a <code>WebformElementDisplayOnBase</code> interface carrying only <code>displayOn</code>, assigned to every element whose plugin implements <code>WebformElementDisplayOnInterface</code>.</li> <li>Narrow <code>WebformElementMarkupBase</code> to the <code>markup</code> field, assigned only to elements that render authored HTML markup (<code>webform_markup</code>; <code>processed_text</code> keeps its dedicated <code>markup</code> resolver).</li> <li>As a result, <code>WebformElementWebformMessage</code>, <code>WebformElementLabel</code>, <code>WebformElementWebformMore</code> and <code>WebformElementView</code> expose <code>displayOn</code> without a <code>markup</code> field.</li> </ul> <p>This is a follow-up to the specialized-elements work in <span class="drupalorg-gitlab-issue-link drupalorg-gitlab-link-wrapper"><a href="https://git.drupalcode.org/project/graphql_webform/-/work_items/3599006" class="drupalorg-gitlab-link">https://git.drupalcode.org/project/graphql_webform/-/work_items/3599006</a></span>; message exposure surfaced the wart but it predates that issue for <code>label</code> / <code>webform_more</code> / <code>view</code>.</p> <h3 id="summary-remaining-tasks">Remaining tasks</h3> <ul> <li>Add the <code>WebformElementDisplayOnBase</code> interface in <code>WebformSchemaBuilder</code> and gate it on <code>WebformElementDisplayOnInterface</code>; narrow <code>WebformElementMarkupBase</code> to <code>markup</code>.</li> <li>Move the <code>displayOn</code> resolver wiring to the new interface in <code>WebformExtension</code>; keep the <code>markup</code> resolver only where markup is populated.</li> <li>Update the per-element tests and the element fixtures so the affected types no longer assert a <code>markup</code> field.</li> <li>Write a change record for the removed <code>markup</code> fields and the interface change.</li> </ul> <h3 id="summary-api-changes">API changes</h3> <p>New <code>WebformElementDisplayOnBase</code> interface exposing <code>displayOn</code> (additive).</p> <p>Breaking: <code>WebformElementMarkupBase</code> no longer declares <code>displayOn</code>, and the <code>markup</code> field is removed from <code>WebformElementWebformMessage</code>, <code>WebformElementLabel</code>, <code>WebformElementWebformMore</code> and <code>WebformElementView</code>. Consumers that selected <code>markup</code> on those types (always <code>null</code>) or relied on <code>displayOn</code> through <code>WebformElementMarkupBase</code> must update their queries. Needs a change record.</p> <h3 id="summary-release-notes">Release notes snippet</h3> <p>Display-only elements (message, label, more, view) no longer expose an always-null <code>markup</code> field; <code>displayOn</code> moved to a dedicated <code>WebformElementDisplayOnBase</code> interface.</p>