Investigate why the Canvas UI seems to not apply client-side transforms
>>> [!note] Migrated issue
<!-- Drupal.org comment -->
<!-- Migrated from issue #3535024. -->
Reported by: [wim leers](https://www.drupal.org/user/99777)
Related to !86 !122
>>>
<h3 id="overview">Overview</h3>
<p>Grab a ☕️ and go and read <span class="drupalorg-gitlab-issue-link drupalorg-gitlab-link-wrapper"><a href="https://git.drupalcode.org/project/canvas/-/work_items/3528396" class="drupalorg-gitlab-link">https://git.drupalcode.org/project/canvas/-/work_items/3528396</a></span>.</p>
<p>Over there, we worked around it purely on the BE, but it's <strong>likely still a bug in the handling of client-side transforms — possibly on the BE not providing them, possibly on the FE not applying them</strong>.</p>
<p>We need to get to the bottom of that still, and ideally would remove the work-around that MR added:</p>
<pre> // 💡 Automatically inform developers of missing client-side transforms,<br> // which is the most likely explanation for a value sent by the XB UI<br> // not being accepted by the field type. However, gracefully degrade and<br> // log a deprecation error.<br> // @see https://en.wikipedia.org/wiki/Robustness_principle<br> if ($source->fieldItemList->count() > 0 && $source->fieldItemList->isEmpty()) {<br> // @todo Investigate in https://www.drupal.org/project/experience_builder/issues/3535024, and preferably add extra guardrails and convert this to an exception<br> // @phpcs:ignore Drupal.Semantics.FunctionTriggerError.TriggerErrorTextLayoutRelaxed<br> @trigger_error(sprintf('Client-side transformation for the `%s` prop failed: `%s` provided, but the %s data type logic considers it to be empty, hence indicating a mismatch.', $prop, json_encode($prop_value), $source->getSourceType()), E_USER_DEPRECATED);<br> continue;<br> }</pre><h3 id="proposed-resolution">Proposed resolution</h3>
<p>TBD, investigate.</p>
<h3 id="ui-changes">User interface changes</h3>
> Related issue: [Issue #3528396](https://www.drupal.org/node/3528396)
> Related issue: [Issue #3549005](https://www.drupal.org/node/3549005)
> Related issue: [Issue #3499554](https://www.drupal.org/node/3499554)
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