🐛 [open-formulieren/open-forms#3572] Fix potential race condition on …

…WebKit

Backport-of: 585

src/components/FormStep/index.js

@@ -406,7 +406,7 @@ const FormStep = ({
    *
    *   - `LOGIC_CHECK_INTERRUPTED` When there's no point/change in state to be expected by the logic
    *       check
-   *   - `BLOCK_SUBMISSION` When the the logic is checking and the form should be disabled for
+   *   - `BLOCK_SUBMISSION` When the logic is checking and the form should be disabled for
    *       submission.
    *   - `LOGIC_CHECK_DONE` When the logic check is done and the form should be enabled for
    *       submission.
@@ -710,7 +710,7 @@ const FormStep = ({
    *
    * During evaluation, the following actions are/may be dispatched:
    *
-   *   - `BLOCK_SUBMISSION` When the the form midfier by a humer (`modifiedByHuman`)  and the form
+   *   - `BLOCK_SUBMISSION` When the form was modified by a human (`modifiedByHuman`)  and the form
    *       should be disabled for submission.
    *   - `ERROR` When an error occurred while evaluating the form logic.
    *   - `FORMIO_CHANGE_HANDLED` When the change is successfully handled .
@@ -726,6 +726,12 @@ const FormStep = ({
   const onFormIOChange = async (changed, flags, modifiedByHuman) => {
     // formio form not mounted -> nothing to do
     if (!formRef.current) return;
+    // Under some conditions and engines (e.g. WebKit), `onFormIOChange` can be triggered while
+    // logicChecking is currently running (that is the scheduled logic check with `setTimeout` is ongoing).
+    // While it is running, `canSubmit` is set to `false` because of the fired `BLOCK_SUBMISSION` action.
+    // We don't want to get in conflict with the current check if the change doesn't come from the user.
+    // See https://github.com/open-formulieren/open-forms/issues/3572 for an example.
+    if (!modifiedByHuman && logicChecking) return;
 
     // backend logic leads to changes in FormIO configuration, which triggers onFormIOInitialized.
     // This in turn triggers the onFormIOChange event because the submission data is set