fix(ivy): adding projectDef instructions to all templates where <ng-content> is present (FW-745) (angular#27384)

Prior to this change `projectDef` instructions were placed to root templates only, thus the necessary information (selectors) in nested templates was missing. This update adds the logic to insert `projectDef` instructions to all templates where <ng-content> is present.

PR Close angular#27384

Author: AndrewKushnir

packages/compiler-cli/test/compliance/r3_compiler_compliance_spec.ts

@@ -1013,7 +1013,7 @@ describe('compiler compliance', () => {
       });
     });
 
-    it('should support content projection', () => {
+    it('should support content projection in root template', () => {
       const files = {
         app: {
           'spec.ts': `
@@ -1061,10 +1061,10 @@ describe('compiler compliance', () => {
         });`;
 
       const ComplexComponentDefinition = `
-        const $c1$ = [[["span", "title", "tofirst"]], [["span", "title", "tosecond"]]];
-        const $c2$ = ["span[title=toFirst]", "span[title=toSecond]"];
         const $c3$ = ["id","first"];
         const $c4$ = ["id","second"];
+        const $c1$ = [[["span", "title", "tofirst"]], [["span", "title", "tosecond"]]];
+        const $c2$ = ["span[title=toFirst]", "span[title=toSecond]"];
         …
         ComplexComponent.ngComponentDef = $r3$.ɵdefineComponent({
           type: ComplexComponent,
@@ -1095,6 +1095,76 @@ describe('compiler compliance', () => {
           result.source, ComplexComponentDefinition, 'Incorrect ComplexComponent definition');
     });
 
+    it('should support content projection in nested templates', () => {
+      const files = {
+        app: {
+          'spec.ts': `
+            import {Component, NgModule} from '@angular/core';
+
+            @Component({
+              template: \`
+                <div id="second" *ngIf="visible">
+                  <ng-content select="span[title=toFirst]"></ng-content>
+                </div>
+                <div id="third" *ngIf="visible">
+                  No ng-content, no instructions generated.
+                </div>
+                <ng-template>
+                  '*' selector: <ng-content></ng-content>
+                </ng-template>
+              \`,
+            })
+            class Cmp {}
+
+            @NgModule({ declarations: [Cmp] })
+            class Module {}
+          `
+        }
+      };
+      const output = `
+        const $_c0$ = [1, "ngIf"];
+        const $_c1$ = ["id", "second"];
+        const $_c2$ = [[["span", "title", "tofirst"]]];
+        const $_c3$ = ["span[title=toFirst]"];
+        function Cmp_div_Template_0(rf, ctx) { if (rf & 1) {
+            $r3$.ɵprojectionDef($_c2$, $_c3$);
+            $r3$.ɵelementStart(0, "div", $_c1$);
+            $r3$.ɵprojection(1, 1);
+            $r3$.ɵelementEnd();
+        } }
+        const $_c4$ = ["id", "third"];
+        function Cmp_div_Template_1(rf, ctx) {
+          if (rf & 1) {
+            $r3$.ɵelementStart(0, "div", $_c4$);
+            $r3$.ɵtext(1, " No ng-content, no instructions generated. ");
+            $r3$.ɵelementEnd();
+          }
+        }
+        function Template_2(rf, ctx) {
+          if (rf & 1) {
+            $r3$.ɵprojectionDef();
+            $r3$.ɵtext(0, " '*' selector: ");
+            $r3$.ɵprojection(1);
+          }
+        }
+        …
+        template: function Cmp_Template(rf, ctx) {
+          if (rf & 1) {
+            $r3$.ɵtemplate(0, Cmp_div_Template_0, 2, 0, null, $_c0$);
+            $r3$.ɵtemplate(1, Cmp_div_Template_1, 2, 0, null, $_c0$);
+            $r3$.ɵtemplate(2, Template_2, 2, 0);
+          }
+          if (rf & 2) {
+            $r3$.ɵelementProperty(0, "ngIf", $r3$.ɵbind(ctx.visible));
+            $r3$.ɵelementProperty(1, "ngIf", $r3$.ɵbind(ctx.visible));
+          }
+        }
+      `;
+
+      const {source} = compile(files, angularFiles);
+      expectEmit(source, output, 'Invalid content projection instructions generated');
+    });
+
     describe('queries', () => {
       const directive = {
         'some.directive.ts': `

packages/compiler/src/render3/r3_ast.ts

@@ -83,7 +83,7 @@ export class Template implements Node {
 
 export class Content implements Node {
   constructor(
-      public selectorIndex: number, public attributes: TextAttribute[],
+      public selector: string, public attributes: TextAttribute[],
       public sourceSpan: ParseSourceSpan, public i18n?: I18nAST) {}
   visit<Result>(visitor: Visitor<Result>): Result { return visitor.visitContent(this); }
 }

packages/compiler/src/render3/r3_template_transform.ts

@@ -45,16 +45,10 @@ const IDENT_PROPERTY_IDX = 9;
 const IDENT_EVENT_IDX = 10;
 
 const TEMPLATE_ATTR_PREFIX = '*';
-// Default selector used by `<ng-content>` if none specified
-const DEFAULT_CONTENT_SELECTOR = '*';
 
 // Result of the html AST to Ivy AST transformation
 export type Render3ParseResult = {
   nodes: t.Node[]; errors: ParseError[];
-  // Any non default (empty or '*') selector found in the template
-  ngContentSelectors: string[];
-  // Wether the template contains any `<ng-content>`
-  hasNgContent: boolean;
 };
 
 export function htmlAstToRender3Ast(
@@ -74,17 +68,11 @@ export function htmlAstToRender3Ast(
   return {
     nodes: ivyNodes,
     errors: allErrors,
-    ngContentSelectors: transformer.ngContentSelectors,
-    hasNgContent: transformer.hasNgContent,
   };
 }
 
 class HtmlAstToIvyAst implements html.Visitor {
   errors: ParseError[] = [];
-  // Selectors for the `ng-content` tags. Only non `*` selectors are recorded here
-  ngContentSelectors: string[] = [];
-  // Any `<ng-content>` in the template ?
-  hasNgContent = false;
 
   constructor(private bindingParser: BindingParser) {}
 
@@ -168,20 +156,12 @@ class HtmlAstToIvyAst implements html.Visitor {
     let parsedElement: t.Node|undefined;
     if (preparsedElement.type === PreparsedElementType.NG_CONTENT) {
       // `<ng-content>`
-      this.hasNgContent = true;
-
       if (element.children && !element.children.every(isEmptyTextNode)) {
         this.reportError(`<ng-content> element cannot have content.`, element.sourceSpan);
       }
-
       const selector = preparsedElement.selectAttr;
-
-      let attributes: t.TextAttribute[] =
-          element.attrs.map(attribute => this.visitAttribute(attribute));
-
-      const selectorIndex =
-          selector === DEFAULT_CONTENT_SELECTOR ? 0 : this.ngContentSelectors.push(selector);
-      parsedElement = new t.Content(selectorIndex, attributes, element.sourceSpan, element.i18n);
+      const attrs: t.TextAttribute[] = element.attrs.map(attr => this.visitAttribute(attr));
+      parsedElement = new t.Content(selector, attrs, element.sourceSpan, element.i18n);
     } else if (isTemplateElement) {
       // `<ng-template>`
       const attrs = this.extractAttributes(element.name, parsedProperties, i18nAttrsMeta);

packages/compiler/src/render3/view/api.ts

@@ -123,16 +123,6 @@ export interface R3ComponentMetadata extends R3DirectiveMetadata {
      * Parsed nodes of the template.
      */
     nodes: t.Node[];
-
-    /**
-     * Whether the template includes <ng-content> tags.
-     */
-    hasNgContent: boolean;
-
-    /**
-     * Selectors found in the <ng-content> tags in the template.
-     */
-    ngContentSelectors: string[];
   };
 
   /**

packages/compiler/src/render3/view/compiler.ts

@@ -258,8 +258,7 @@ export function compileComponentFromMetadata(
       meta.viewQueries, directiveMatcher, directivesUsed, meta.pipes, pipesUsed, R3.namespaceHTML,
       meta.relativeContextFilePath, meta.i18nUseExternalIds);
 
-  const templateFunctionExpression = templateBuilder.buildTemplateFunction(
-      template.nodes, [], template.hasNgContent, template.ngContentSelectors);
+  const templateFunctionExpression = templateBuilder.buildTemplateFunction(template.nodes, []);
 
   // e.g. `consts: 2`
   definitionMap.set('consts', o.literal(templateBuilder.getConstCount()));
@@ -371,11 +370,7 @@ export function compileComponentFromRender2(
   const meta: R3ComponentMetadata = {
     ...directiveMetadataFromGlobalMetadata(component, outputCtx, reflector),
     selector: component.selector,
-    template: {
-      nodes: render3Ast.nodes,
-      hasNgContent: render3Ast.hasNgContent,
-      ngContentSelectors: render3Ast.ngContentSelectors,
-    },
+    template: {nodes: render3Ast.nodes},
     directives: [],
     pipes: typeMapToExpressionMap(pipeTypeByName, outputCtx),
     viewQueries: queriesFromGlobalMetadata(component.viewQueries, outputCtx),

packages/compiler/src/render3/view/template.ts

@@ -58,6 +58,8 @@ export function renderFlagCheckIfStmt(
   return o.ifStmt(o.variable(RENDER_FLAGS).bitwiseAnd(o.literal(flags), null, false), statements);
 }
 
+// Default selector used by `<ng-content>` if none specified
+const DEFAULT_CONTENT_SELECTOR = '*';
 export class TemplateDefinitionBuilder implements t.Visitor<void>, LocalResolver {
   private _dataIndex = 0;
   private _bindingContext = 0;
@@ -102,6 +104,12 @@ export class TemplateDefinitionBuilder implements t.Visitor<void>, LocalResolver
 
   private fileBasedI18nSuffix: string;
 
+  // Whether the template includes <ng-content> tags.
+  private _hasNgContent: boolean = false;
+
+  // Selectors found in the <ng-content> tags in the template.
+  private _ngContentSelectors: string[] = [];
+
   constructor(
       private constantPool: ConstantPool, parentBindingScope: BindingScope, private level = 0,
       private contextName: string|null, private i18nContext: I18nContext|null,
@@ -154,32 +162,14 @@ export class TemplateDefinitionBuilder implements t.Visitor<void>, LocalResolver
         });
   }
 
-  buildTemplateFunction(
-      nodes: t.Node[], variables: t.Variable[], hasNgContent: boolean = false,
-      ngContentSelectors: string[] = [], i18n?: i18n.AST): o.FunctionExpr {
+  buildTemplateFunction(nodes: t.Node[], variables: t.Variable[], i18n?: i18n.AST): o.FunctionExpr {
     if (this._namespace !== R3.namespaceHTML) {
       this.creationInstruction(null, this._namespace);
     }
 
     // Create variable bindings
     variables.forEach(v => this.registerContextVariables(v));
 
-    // Output a `ProjectionDef` instruction when some `<ng-content>` are present
-    if (hasNgContent) {
-      const parameters: o.Expression[] = [];
-
-      // Only selectors with a non-default value are generated
-      if (ngContentSelectors.length > 1) {
-        const r3Selectors = ngContentSelectors.map(s => core.parseSelectorToR3Selector(s));
-        // `projectionDef` needs both the parsed and raw value of the selectors
-        const parsed = this.constantPool.getConstLiteral(asLiteral(r3Selectors), true);
-        const unParsed = this.constantPool.getConstLiteral(asLiteral(ngContentSelectors), true);
-        parameters.push(parsed, unParsed);
-      }
-
-      this.creationInstruction(null, R3.projectionDef, parameters);
-    }
-
     // Initiate i18n context in case:
     // - this template has parent i18n context
     // - or the template has i18n meta associated with it,
@@ -198,6 +188,26 @@ export class TemplateDefinitionBuilder implements t.Visitor<void>, LocalResolver
     // resolving bindings. We also count bindings in this pass as we walk bound expressions.
     t.visitAll(this, nodes);
 
+    // Output a `ProjectionDef` instruction when some `<ng-content>` are present
+    if (this._hasNgContent) {
+      const parameters: o.Expression[] = [];
+
+      // Only selectors with a non-default value are generated
+      if (this._ngContentSelectors.length) {
+        const r3Selectors = this._ngContentSelectors.map(s => core.parseSelectorToR3Selector(s));
+        // `projectionDef` needs both the parsed and raw value of the selectors
+        const parsed = this.constantPool.getConstLiteral(asLiteral(r3Selectors), true);
+        const unParsed =
+            this.constantPool.getConstLiteral(asLiteral(this._ngContentSelectors), true);
+        parameters.push(parsed, unParsed);
+      }
+
+      // Since we accumulate ngContent selectors while processing template elements,
+      // we *prepend* `projectionDef` to creation instructions block, to put it before
+      // any `projection` instructions
+      this.creationInstruction(null, R3.projectionDef, parameters, /* prepend */ true);
+    }
+
     // Add total binding count to pure function count so pure function instructions are
     // generated with the correct slot offset when update instructions are processed.
     this._pureFunctionSlots += this._bindingSlots;
@@ -399,8 +409,11 @@ export class TemplateDefinitionBuilder implements t.Visitor<void>, LocalResolver
   }
 
   visitContent(ngContent: t.Content) {
+    this._hasNgContent = true;
     const slot = this.allocateDataSlot();
-    const selectorIndex = ngContent.selectorIndex;
+    let selectorIndex = ngContent.selector === DEFAULT_CONTENT_SELECTOR ?
+        0 :
+        this._ngContentSelectors.push(ngContent.selector);
     const parameters: o.Expression[] = [o.literal(slot)];
 
     const attributeAsList: string[] = [];
@@ -724,7 +737,7 @@ export class TemplateDefinitionBuilder implements t.Visitor<void>, LocalResolver
     // template definition. e.g. <div *ngIf="showing"> {{ foo }} </div>  <div #foo></div>
     this._nestedTemplateFns.push(() => {
       const templateFunctionExpr = templateVisitor.buildTemplateFunction(
-          template.children, template.variables, false, [], template.i18n);
+          template.children, template.variables, template.i18n);
       this.constantPool.statements.push(templateFunctionExpr.toDeclStmt(templateName, null));
     });
 
@@ -834,8 +847,8 @@ export class TemplateDefinitionBuilder implements t.Visitor<void>, LocalResolver
   // bindings. e.g. {{ foo }} <div #foo></div>
   private instructionFn(
       fns: (() => o.Statement)[], span: ParseSourceSpan|null, reference: o.ExternalReference,
-      paramsOrFn: o.Expression[]|(() => o.Expression[])): void {
-    fns.push(() => {
+      paramsOrFn: o.Expression[]|(() => o.Expression[]), prepend: boolean = false): void {
+    fns[prepend ? 'unshift' : 'push'](() => {
       const params = Array.isArray(paramsOrFn) ? paramsOrFn : paramsOrFn();
       return instruction(span, reference, params).toStmt();
     });
@@ -856,8 +869,8 @@ export class TemplateDefinitionBuilder implements t.Visitor<void>, LocalResolver
 
   private creationInstruction(
       span: ParseSourceSpan|null, reference: o.ExternalReference,
-      paramsOrFn?: o.Expression[]|(() => o.Expression[])) {
-    this.instructionFn(this._creationCodeFns, span, reference, paramsOrFn || []);
+      paramsOrFn?: o.Expression[]|(() => o.Expression[]), prepend?: boolean) {
+    this.instructionFn(this._creationCodeFns, span, reference, paramsOrFn || [], prepend);
   }
 
   private updateInstruction(
@@ -1398,14 +1411,14 @@ function interpolate(args: o.Expression[]): o.Expression {
 export function parseTemplate(
     template: string, templateUrl: string,
     options: {preserveWhitespaces?: boolean, interpolationConfig?: InterpolationConfig} = {}):
-    {errors?: ParseError[], nodes: t.Node[], hasNgContent: boolean, ngContentSelectors: string[]} {
+    {errors?: ParseError[], nodes: t.Node[]} {
   const {interpolationConfig, preserveWhitespaces} = options;
   const bindingParser = makeBindingParser(interpolationConfig);
   const htmlParser = new HtmlParser();
   const parseResult = htmlParser.parse(template, templateUrl, true, interpolationConfig);
 
   if (parseResult.errors && parseResult.errors.length > 0) {
-    return {errors: parseResult.errors, nodes: [], hasNgContent: false, ngContentSelectors: []};
+    return {errors: parseResult.errors, nodes: []};
   }
 
   let rootNodes: html.Node[] = parseResult.rootNodes;
@@ -1428,13 +1441,12 @@ export function parseTemplate(
         new I18nMetaVisitor(interpolationConfig, /* keepI18nAttrs */ false), rootNodes);
   }
 
-  const {nodes, hasNgContent, ngContentSelectors, errors} =
-      htmlAstToRender3Ast(rootNodes, bindingParser);
+  const {nodes, errors} = htmlAstToRender3Ast(rootNodes, bindingParser);
   if (errors && errors.length > 0) {
-    return {errors, nodes: [], hasNgContent: false, ngContentSelectors: []};
+    return {errors, nodes: []};
   }
 
-  return {nodes, hasNgContent, ngContentSelectors};
+  return {nodes};
 }
 
 /**