Hide children section for milestones

https://community.openproject.org/work_packages/54983

frontend/src/app/features/work-packages/components/wp-relations/wp-relations-hierarchy/wp-relations-hierarchy.directive.ts

@@ -33,12 +33,13 @@ import { PathHelperService } from 'core-app/core/path-helper/path-helper.service
 import {
   WorkPackageRelationsHierarchyService,
 } from 'core-app/features/work-packages/components/wp-relations/wp-relations-hierarchy/wp-relations-hierarchy.service';
-import { take } from 'rxjs/operators';
+import { take, withLatestFrom } from 'rxjs/operators';
 import { UntilDestroyedMixin } from 'core-app/shared/helpers/angular/until-destroyed.mixin';
 import { ApiV3Service } from 'core-app/core/apiv3/api-v3.service';
 import {
   WorkPackageIsolatedQuerySpaceDirective,
 } from 'core-app/features/work-packages/directives/query-space/wp-isolated-query-space.directive';
+import { SchemaCacheService } from 'core-app/core/schemas/schema-cache.service';
 
 @Component({
   selector: 'wp-relations-hierarchy',
@@ -54,18 +55,21 @@ export class WorkPackageRelationsHierarchyComponent extends UntilDestroyedMixin
 
   public workPackagePath:string;
 
-  public canHaveChildren:boolean;
+  public canHaveChildren = false;
 
   public canModifyHierarchy:boolean;
 
   public canAddRelation:boolean;
 
   public childrenQueryProps:any;
 
-  constructor(protected wpRelationsHierarchyService:WorkPackageRelationsHierarchyService,
-    protected apiV3Service:ApiV3Service,
-    protected PathHelper:PathHelperService,
-    readonly I18n:I18nService) {
+  constructor(
+    readonly wpRelationsHierarchyService:WorkPackageRelationsHierarchyService,
+    readonly apiV3Service:ApiV3Service,
+    readonly PathHelper:PathHelperService,
+    readonly I18n:I18nService,
+    readonly schemaCache:SchemaCacheService,
+  ) {
     super();
   }
 
@@ -91,10 +95,12 @@ export class WorkPackageRelationsHierarchyComponent extends UntilDestroyedMixin
       .id(this.workPackage)
       .requireAndStream()
       .pipe(
+        withLatestFrom(this.schemaCache.requireAndStream(this.workPackage.href as string)),
         this.untilDestroyed(),
       )
-      .subscribe((wp:WorkPackageResource) => {
+      .subscribe(([wp, schema]) => {
         this.workPackage = wp;
+        this.canHaveChildren = !schema.isMilestone as boolean;
 
         const parentId = this.workPackage.parent?.id?.toString();
 

frontend/src/app/features/work-packages/components/wp-relations/wp-relations-hierarchy/wp-relations-hierarchy.template.html

@@ -1,4 +1,6 @@
-<div class="wp-relations-hierarchy-section wp-relations--children">
+<div
+  *ngIf="canHaveChildren"
+  class="wp-relations-hierarchy-section wp-relations--children">
   <div class="attributes-group--header">
     <div class="attributes-group--header-container">
       <h3 class="attributes-group--header-text"

spec/features/work_packages/details/relations/hierarchy_milestone_spec.rb

@@ -54,5 +54,7 @@
       expect(page).to have_no_text("Create new child")
       expect(page).to have_no_css("wp-inline-create--add-link")
     end
+
+    expect(page).to have_no_text("Children")
   end
 end