fix(ivy): Class selector directives execute properly on container elements (#29383)

PR Close #29383

packages/core/src/render3/instructions/instructions.ts

@@ -547,6 +547,13 @@ export function elementContainerStart(
   const tNode =
       createNodeAtIndex(index, TNodeType.ElementContainer, native, tagName, attrs || null);
 
+
+  if (attrs) {
+    // While ng-container doesn't necessarily support styling, we use the style context to identify
+    // and execute directives on the ng-container.
+    setNodeStylingTemplate(tView, tNode, attrs, 0);
+  }
+
   appendChild(native, tNode, lView);
   createDirectivesAndLocals(tView, lView, localRefs);
   attachPatchData(native, lView);
@@ -559,6 +566,25 @@ export function elementContainerStart(
   executeContentQueries(tView, tNode, lView);
 }
 
+/**
+ * Appropriately sets `stylingTemplate` on a TNode
+ *
+ * Does not apply styles to DOM nodes
+ *
+ * @param tNode The node whose `stylingTemplate` to set
+ * @param attrs The attribute array source to set the attributes from
+ * @param attrsStartIndex Optional start index to start processing the `attrs` from
+ */
+function setNodeStylingTemplate(
+    tView: TView, tNode: TNode, attrs: TAttributes, attrsStartIndex: number) {
+  if (tView.firstTemplatePass && !tNode.stylingTemplate) {
+    const stylingAttrsStartIndex = attrsStylingIndexOf(attrs, attrsStartIndex);
+    if (stylingAttrsStartIndex >= 0) {
+      tNode.stylingTemplate = initializeStaticStylingContext(attrs, stylingAttrsStartIndex);
+    }
+  }
+}
+
 function executeContentQueries(tView: TView, tNode: TNode, lView: LView) {
   if (isContentQueryHost(tNode)) {
     const start = tNode.directiveStart;
@@ -636,12 +662,7 @@ export function elementStart(
     // value is evaluated). When the template is allocated (when it turns into a context)
     // then the styling template is locked and cannot be further extended (it can only be
     // instantiated into a context per element)
-    if (tView.firstTemplatePass && !tNode.stylingTemplate) {
-      const stylingAttrsStartIndex = attrsStylingIndexOf(attrs, lastAttrIndex);
-      if (stylingAttrsStartIndex >= 0) {
-        tNode.stylingTemplate = initializeStaticStylingContext(attrs, stylingAttrsStartIndex);
-      }
-    }
+    setNodeStylingTemplate(tView, tNode, attrs, lastAttrIndex);
 
     if (tNode.stylingTemplate) {
       // the initial style/class values are rendered immediately after having been

packages/core/test/acceptance/content_spec.ts

@@ -166,5 +166,63 @@ describe('projection', () => {
       fixture.detectChanges();
       expect(fixture.nativeElement).toHaveText('inline()ng-template(onetwothree)');
     });
+
+    describe('on containers', () => {
+      it('should work when matching attributes', () => {
+        let xDirectives = 0;
+        @Component({selector: 'selector-proj', template: '<ng-content select="[x]"></ng-content>'})
+        class SelectedNgContentComp {
+        }
+
+        @Directive({selector: '[x]'})
+        class XDirective {
+          constructor() { xDirectives++; }
+        }
+
+        @Component({
+          selector: 'main-selector',
+          template:
+              '<selector-proj><ng-container x="true">Hello world!</ng-container></selector-proj>'
+        })
+        class SelectorMainComp {
+        }
+
+        TestBed.configureTestingModule(
+            {declarations: [XDirective, SelectedNgContentComp, SelectorMainComp]});
+        const fixture = TestBed.createComponent<SelectorMainComp>(SelectorMainComp);
+
+        fixture.detectChanges();
+        expect(fixture.nativeElement).toHaveText('Hello world!');
+        expect(xDirectives).toEqual(1);
+      });
+
+      it('should work when matching classes', () => {
+        let xDirectives = 0;
+        @Component({selector: 'selector-proj', template: '<ng-content select=".x"></ng-content>'})
+        class SelectedNgContentComp {
+        }
+
+        @Directive({selector: '.x'})
+        class XDirective {
+          constructor() { xDirectives++; }
+        }
+
+        @Component({
+          selector: 'main-selector',
+          template:
+              '<selector-proj><ng-container class="x">Hello world!</ng-container></selector-proj>'
+        })
+        class SelectorMainComp {
+        }
+
+        TestBed.configureTestingModule(
+            {declarations: [XDirective, SelectedNgContentComp, SelectorMainComp]});
+        const fixture = TestBed.createComponent<SelectorMainComp>(SelectorMainComp);
+
+        fixture.detectChanges();
+        expect(fixture.nativeElement).toHaveText('Hello world!');
+        expect(xDirectives).toEqual(1);
+      });
+    });
   });
-});
+});

packages/core/test/bundling/cyclic_import/bundle.golden_symbols.json

@@ -659,6 +659,9 @@
   {
     "name": "setIsParent"
   },
+  {
+    "name": "setNodeStylingTemplate"
+  },
   {
     "name": "setPreviousOrParentTNode"
   },

packages/core/test/bundling/todo/bundle.golden_symbols.json

@@ -1271,6 +1271,9 @@
   {
     "name": "setIsParent"
   },
+  {
+    "name": "setNodeStylingTemplate"
+  },
   {
     "name": "setPlayerBuilder"
   },