fix(submission): keep dc.type dropdown display after change

src/app/shared/form/builder/ds-dynamic-form-ui/ds-dynamic-type-bind-relation.service.spec.ts

@@ -86,7 +86,7 @@ describe('DSDynamicTypeBindRelationService test suite', () => {
     it('Should not push undefined bind models', () => {
       const testModel = mockInputWithTypeBindModel;
       testModel.typeBindRelations = getTypeBindRelations(['boundType']);
-      spyOn((service as any).formBuilderService, 'getTypeBindModel').and.returnValue(undefined);
+      ((service as any).formBuilderService.getTypeBindModel as jasmine.Spy).and.returnValue(undefined);
 
       const relatedModels = service.getRelatedFormModel(testModel);
 
@@ -143,7 +143,7 @@ describe('DSDynamicTypeBindRelationService test suite', () => {
         opposingMatch: HIDDEN_MATCHER.match,
         onChange: jasmine.createSpy('onChange')
       };
-      spyOn((service as any).formBuilderService, 'getTypeBindModel').and.returnValue(undefined);
+      ((service as any).formBuilderService.getTypeBindModel as jasmine.Spy).and.returnValue(undefined);
 
       const hasMatch = service.matchesCondition(relation, visibleMatcher);
 
@@ -159,7 +159,7 @@ describe('DSDynamicTypeBindRelationService test suite', () => {
         opposingMatch: MATCH_VISIBLE,
         onChange: jasmine.createSpy('onChange')
       };
-      spyOn((service as any).formBuilderService, 'getTypeBindModel').and.returnValue(undefined);
+      ((service as any).formBuilderService.getTypeBindModel as jasmine.Spy).and.returnValue(undefined);
 
       const hasMatch = service.matchesCondition(relation, hiddenMatcher);
 
@@ -185,8 +185,8 @@ describe('DSDynamicTypeBindRelationService test suite', () => {
         onChange: jasmine.createSpy('onChange')
       };
       (service as any).dynamicMatchers = [visibleMatcher];
-      spyOn((service as any).formBuilderService, 'getTypeBindModel').and.callFake(() => bindModelAvailable ? bindModel : undefined);
-      spyOn((service as any).formBuilderService, 'getTypeBindModelUpdates').and.returnValue(bindModelUpdates$.asObservable());
+      ((service as any).formBuilderService.getTypeBindModel as jasmine.Spy).and.callFake(() => bindModelAvailable ? bindModel : undefined);
+      ((service as any).formBuilderService.getTypeBindModelUpdates as jasmine.Spy).and.returnValue(bindModelUpdates$.asObservable());
 
       const subscriptions = service.subscribeRelations(testModel, dcTypeControl);
       expect(subscriptions.length).toBe(1);
@@ -220,8 +220,8 @@ describe('DSDynamicTypeBindRelationService test suite', () => {
         onChange: jasmine.createSpy('onChange')
       };
       (service as any).dynamicMatchers = [hiddenMatcher];
-      spyOn((service as any).formBuilderService, 'getTypeBindModel').and.callFake(() => bindModelAvailable ? bindModel : undefined);
-      spyOn((service as any).formBuilderService, 'getTypeBindModelUpdates').and.returnValue(bindModelUpdates$.asObservable());
+      ((service as any).formBuilderService.getTypeBindModel as jasmine.Spy).and.callFake(() => bindModelAvailable ? bindModel : undefined);
+      ((service as any).formBuilderService.getTypeBindModelUpdates as jasmine.Spy).and.returnValue(bindModelUpdates$.asObservable());
 
       const subscriptions = service.subscribeRelations(testModel, dcTypeControl);
       expect(subscriptions.length).toBe(1);
@@ -254,8 +254,8 @@ describe('DSDynamicTypeBindRelationService test suite', () => {
         onChange: jasmine.createSpy('onChange')
       };
       (service as any).dynamicMatchers = [visibleMatcher];
-      spyOn((service as any).formBuilderService, 'getTypeBindModel').and.callFake(() => bindModelAvailable ? bindModel : undefined);
-      spyOn((service as any).formBuilderService, 'getTypeBindModelUpdates').and.returnValue(bindModelUpdates$.asObservable());
+      ((service as any).formBuilderService.getTypeBindModel as jasmine.Spy).and.callFake(() => bindModelAvailable ? bindModel : undefined);
+      ((service as any).formBuilderService.getTypeBindModelUpdates as jasmine.Spy).and.returnValue(bindModelUpdates$.asObservable());
 
       const subscriptions = service.subscribeRelations(testModel, dcTypeControl);
       expect(visibleMatcher.onChange).toHaveBeenCalledWith(false, testModel, dcTypeControl, jasmine.anything());

src/app/shared/form/builder/ds-dynamic-form-ui/models/scrollable-dropdown/dynamic-scrollable-dropdown.component.spec.ts

@@ -5,6 +5,7 @@ import { ComponentFixture, fakeAsync, inject, TestBed, tick, waitForAsync, } fro
 import { By } from '@angular/platform-browser';
 import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
 import { TranslateModule } from '@ngx-translate/core';
+import { of as observableOf } from 'rxjs';
 import { InfiniteScrollModule } from 'ngx-infinite-scroll';
 import { DynamicFormLayoutService, DynamicFormsCoreModule, DynamicFormValidationService } from '@ng-dynamic-forms/core';
 import { DynamicFormsNGBootstrapUIModule } from '@ng-dynamic-forms/ui-ng-bootstrap';
@@ -15,6 +16,7 @@ import { VocabularyServiceStub } from '../../../../../testing/vocabulary-service
 import { DsDynamicScrollableDropdownComponent } from './dynamic-scrollable-dropdown.component';
 import { DynamicScrollableDropdownModel } from './dynamic-scrollable-dropdown.model';
 import { VocabularyEntry } from '../../../../../../core/submission/vocabularies/models/vocabulary-entry.model';
+import { FormFieldMetadataValueObject } from '../../../models/form-field-metadata-value.model';
 import { createTestComponent, hasClass } from '../../../../../testing/utils.test';
 import {
   mockDynamicFormLayoutService,
@@ -209,6 +211,50 @@ describe('Dynamic Dynamic Scrollable Dropdown component', () => {
         expect(scrollableDropdownComp.optionsList).toEqual(vocabularyServiceStub.getList());
         expect(scrollableDropdownComp.model.value).toEqual(modelValue);
       });
+
+      it('should fall back to the underlying value when display is empty on value change', () => {
+        const valueWithEmptyDisplay = { display: '', value: 'Corpus' };
+        scrollableDropdownComp.setCurrentValue(valueWithEmptyDisplay);
+
+        let currentValue;
+        scrollableDropdownComp.currentValue.subscribe((v) => currentValue = v);
+
+        expect(currentValue).toBe('Corpus');
+      });
+
+      it('should fall back to the underlying value when display is empty on init', () => {
+        // Build the value bypassing the FormFieldMetadataValueObject constructor (which would
+        // otherwise apply its own `display || value`), so the init branch genuinely receives an
+        // empty display and exercises the fallback in setCurrentValue.
+        const emptyDisplayValue = Object.assign(
+          new FormFieldMetadataValueObject(),
+          { display: '', value: 'Corpus' }
+        );
+        spyOn(scrollableDropdownComp, 'getInitValueFromModel').and.returnValue(observableOf(emptyDisplayValue));
+        scrollableDropdownComp.setCurrentValue(emptyDisplayValue, true);
+
+        let currentValue;
+        scrollableDropdownComp.currentValue.subscribe((v) => currentValue = v);
+
+        expect(currentValue).toBe('Corpus');
+      });
+
+      // Regression for ufal/clarin-dspace#1377: after a dc.type change the section
+      // reloads and pushes a new value with an empty display through the form control.
+      // The rendered input must not blank out.
+      it('should keep the rendered value when a value with empty display arrives via valueChanges', fakeAsync(() => {
+        const reloadedValue = Object.assign(
+          new FormFieldMetadataValueObject(),
+          { display: '', value: 'Corpus', authority: 'corpus-auth' }
+        );
+
+        scrollableDropdownComp.group.get(scrollableDropdownComp.model.id).setValue(reloadedValue);
+        tick();
+        scrollableDropdownFixture.detectChanges();
+
+        const input = scrollableDropdownFixture.debugElement.query(By.css('input.form-control')).nativeElement;
+        expect(input.value).toBe('Corpus');
+      }));
     });
   });
 });

src/app/shared/form/builder/ds-dynamic-form-ui/models/scrollable-dropdown/dynamic-scrollable-dropdown.component.ts

@@ -276,7 +276,7 @@ export class DsDynamicScrollableDropdownComponent extends DsDynamicVocabularyCom
 
     if (init && !this.useFindAllService) {
       result = this.getInitValueFromModel().pipe(
-        map((formValue: FormFieldMetadataValueObject) => formValue.display)
+        map((formValue: FormFieldMetadataValueObject) => formValue.display || formValue.value)
       );
     } else {
       if (isEmpty(value)) {
@@ -286,7 +286,7 @@ export class DsDynamicScrollableDropdownComponent extends DsDynamicVocabularyCom
       } else if (this.useFindAllService) {
         result = observableOf(value[this.model.displayKey]);
       } else {
-        result = observableOf(value.display);
+        result = observableOf(value.display || value.value);
       }
     }