LIBDRUM-909. Fix race condition in validation error display after deposit

docs/DrumAngularCustomizations.md

@@ -80,3 +80,22 @@ would successfully complete:
 
 * Commented out the "codecov" job, because UMD does not have an appropriate key
   for uploading the results to codecov.io.
+
+## Change to Submission Form Validation Handling
+
+The "updateForm" method in the "SubmissionSectionFormComponent" class
+(src/app/submission/sections/form/section-form.component.ts) has been
+modified to clear the form validation errors held by Angular when
+receiving a form update from the back-end.
+
+This change is intended to fix an issue (see LIBDRUM-909) in which submitting
+a form without all the required fields populated would only show a brief
+"flash" of the validation errors, and then not show GUI validation
+warnings on all affected fields. This is apparently caused by a race condition
+between the Angular validation handling, and a page refresh triggered by the
+DSpace backend response.
+
+It is unclear whether this is the optimal fix, so it has not been submitted
+upstream to DSpace. Also, DSpace has been working on various similar fixes, so
+the changes in this class should be re-evaluated on upgrades, and
+removed if possible.

src/app/submission/sections/form/section-form.component.ts

@@ -370,6 +370,20 @@ export class SubmissionSectionFormComponent extends SectionModelComponent {
         this.isUpdating = true;
         this.formModel = null;
         this.cdr.detectChanges();
+        // UMD Customization
+        // Clear errors before calling initForm.
+        // This is needed because this code path may be called multiple times,
+        // and checksForErrors does a no-op (essentially clearing the
+        // validation errors) if the "this.sectionData.errorsToShow" hasn't
+        // changed.
+        // Clearing the "errorsToShow" ensures that checksForErrors actually
+        // shows the errors, no matter how many times this code block is called.
+        //
+        // Note: Future DSpace changes may eliminate the need for this change,
+        // so it should be checked when doing DSpace upgrades, and removed,
+        // if possible.
+        this.sectionData.errorsToShow = [];
+        // End UMD Customization
         this.initForm(sectionData, errors, sectionState.serverValidationErrors);
         this.checksForErrors(errors);
         this.isUpdating = false;