refactor(compiler): element.startSourceSpan is required (#38581)

Previously, the `startSourceSpan` property could be null
but in reality it is always well defined - except for a legacy
case in the old i18n extraction/merging code, where the
typings for source-spans are already being undermined.

Making this property non-null, simplifies code elsewhere
in the project.

PR Close #38581

packages/compiler/src/i18n/extractor_merger.ts

@@ -124,7 +124,7 @@ class _Visitor implements html.Visitor {
     this._translations = translations;
 
     // Construct a single fake root element
-    const wrapper = new html.Element('wrapper', [], nodes, undefined!, undefined, undefined);
+    const wrapper = new html.Element('wrapper', [], nodes, undefined!, undefined!, undefined);
 
     const translatedNode = wrapper.visit(this, null);
 
@@ -492,7 +492,7 @@ class _Visitor implements html.Visitor {
   }
 
   private _reportError(node: html.Node, msg: string): void {
-    this._errors.push(new I18nError(node.sourceSpan!, msg));
+    this._errors.push(new I18nError(node.sourceSpan, msg));
   }
 }
 

packages/compiler/src/i18n/i18n_parser.ts

@@ -83,7 +83,7 @@ class _I18nVisitor implements html.Visitor {
     const isVoid: boolean = getHtmlTagDefinition(el.name).isVoid;
     const startPhName =
         context.placeholderRegistry.getStartTagPlaceholderName(el.name, attrs, isVoid);
-    context.placeholderToContent[startPhName] = el.sourceSpan!.toString();
+    context.placeholderToContent[startPhName] = el.sourceSpan.toString();
 
     let closePhName = '';
 
@@ -93,7 +93,7 @@ class _I18nVisitor implements html.Visitor {
     }
 
     const node = new i18n.TagPlaceholder(
-        el.name, attrs, startPhName, closePhName, children, isVoid, el.sourceSpan!);
+        el.name, attrs, startPhName, closePhName, children, isVoid, el.sourceSpan);
     return context.visitNodeFn(el, node);
   }
 
@@ -103,7 +103,7 @@ class _I18nVisitor implements html.Visitor {
   }
 
   visitText(text: html.Text, context: I18nMessageVisitorContext): i18n.Node {
-    const node = this._visitTextWithInterpolation(text.value, text.sourceSpan!, context);
+    const node = this._visitTextWithInterpolation(text.value, text.sourceSpan, context);
     return context.visitNodeFn(text, node);
   }
 

packages/compiler/src/i18n/serializers/xliff.ts

@@ -231,9 +231,9 @@ class XliffParser implements ml.Visitor {
         break;
 
       case _TARGET_TAG:
-        const innerTextStart = element.startSourceSpan!.end.offset;
+        const innerTextStart = element.startSourceSpan.end.offset;
         const innerTextEnd = element.endSourceSpan!.start.offset;
-        const content = element.startSourceSpan!.start.file.content;
+        const content = element.startSourceSpan.start.file.content;
         const innerText = content.slice(innerTextStart, innerTextEnd);
         this._unitMlString = innerText;
         break;
@@ -264,7 +264,7 @@ class XliffParser implements ml.Visitor {
   visitExpansionCase(expansionCase: ml.ExpansionCase, context: any): any {}
 
   private _addError(node: ml.Node, message: string): void {
-    this._errors.push(new I18nError(node.sourceSpan!, message));
+    this._errors.push(new I18nError(node.sourceSpan, message));
   }
 }
 
@@ -288,14 +288,14 @@ class XmlToI18n implements ml.Visitor {
   }
 
   visitText(text: ml.Text, context: any) {
-    return new i18n.Text(text.value, text.sourceSpan!);
+    return new i18n.Text(text.value, text.sourceSpan);
   }
 
   visitElement(el: ml.Element, context: any): i18n.Placeholder|ml.Node[]|null {
     if (el.name === _PLACEHOLDER_TAG) {
       const nameAttr = el.attrs.find((attr) => attr.name === 'id');
       if (nameAttr) {
-        return new i18n.Placeholder('', nameAttr.value, el.sourceSpan!);
+        return new i18n.Placeholder('', nameAttr.value, el.sourceSpan);
       }
 
       this._addError(el, `<${_PLACEHOLDER_TAG}> misses the "id" attribute`);
@@ -332,7 +332,7 @@ class XmlToI18n implements ml.Visitor {
   visitAttribute(attribute: ml.Attribute, context: any) {}
 
   private _addError(node: ml.Node, message: string): void {
-    this._errors.push(new I18nError(node.sourceSpan!, message));
+    this._errors.push(new I18nError(node.sourceSpan, message));
   }
 }
 

packages/compiler/src/i18n/serializers/xliff2.ts

@@ -246,9 +246,9 @@ class Xliff2Parser implements ml.Visitor {
         break;
 
       case _TARGET_TAG:
-        const innerTextStart = element.startSourceSpan!.end.offset;
+        const innerTextStart = element.startSourceSpan.end.offset;
         const innerTextEnd = element.endSourceSpan!.start.offset;
-        const content = element.startSourceSpan!.start.file.content;
+        const content = element.startSourceSpan.start.file.content;
         const innerText = content.slice(innerTextStart, innerTextEnd);
         this._unitMlString = innerText;
         break;

packages/compiler/src/i18n/serializers/xtb.ts

@@ -130,9 +130,9 @@ class XtbParser implements ml.Visitor {
           if (this._msgIdToHtml.hasOwnProperty(id)) {
             this._addError(element, `Duplicated translations for msg ${id}`);
           } else {
-            const innerTextStart = element.startSourceSpan!.end.offset;
+            const innerTextStart = element.startSourceSpan.end.offset;
             const innerTextEnd = element.endSourceSpan!.start.offset;
-            const content = element.startSourceSpan!.start.file.content;
+            const content = element.startSourceSpan.start.file.content;
             const innerText = content.slice(innerTextStart!, innerTextEnd!);
             this._msgIdToHtml[id] = innerText;
           }
@@ -155,7 +155,7 @@ class XtbParser implements ml.Visitor {
   visitExpansionCase(expansionCase: ml.ExpansionCase, context: any): any {}
 
   private _addError(node: ml.Node, message: string): void {
-    this._errors.push(new I18nError(node.sourceSpan!, message));
+    this._errors.push(new I18nError(node.sourceSpan, message));
   }
 }
 
@@ -179,7 +179,7 @@ class XmlToI18n implements ml.Visitor {
   }
 
   visitText(text: ml.Text, context: any) {
-    return new i18n.Text(text.value, text.sourceSpan!);
+    return new i18n.Text(text.value, text.sourceSpan);
   }
 
   visitExpansion(icu: ml.Expansion, context: any) {
@@ -203,7 +203,7 @@ class XmlToI18n implements ml.Visitor {
     if (el.name === _PLACEHOLDER_TAG) {
       const nameAttr = el.attrs.find((attr) => attr.name === 'name');
       if (nameAttr) {
-        return new i18n.Placeholder('', nameAttr.value, el.sourceSpan!);
+        return new i18n.Placeholder('', nameAttr.value, el.sourceSpan);
       }
 
       this._addError(el, `<${_PLACEHOLDER_TAG}> misses the "name" attribute`);
@@ -218,6 +218,6 @@ class XmlToI18n implements ml.Visitor {
   visitAttribute(attribute: ml.Attribute, context: any) {}
 
   private _addError(node: ml.Node, message: string): void {
-    this._errors.push(new I18nError(node.sourceSpan!, message));
+    this._errors.push(new I18nError(node.sourceSpan, message));
   }
 }

packages/compiler/src/ml_parser/ast.ts

@@ -64,7 +64,7 @@ export class Attribute extends NodeWithI18n {
 export class Element extends NodeWithI18n {
   constructor(
       public name: string, public attrs: Attribute[], public children: Node[],
-      sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan|null = null,
+      sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan,
       public endSourceSpan: ParseSourceSpan|null = null, i18n?: I18nMeta) {
     super(sourceSpan, i18n);
   }

packages/compiler/src/render3/r3_ast.ts

@@ -79,13 +79,8 @@ export class Element implements Node {
   constructor(
       public name: string, public attributes: TextAttribute[], public inputs: BoundAttribute[],
       public outputs: BoundEvent[], public children: Node[], public references: Reference[],
-      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan|null,
+      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan,
-      public endSourceSpan: ParseSourceSpan|null, public i18n?: I18nMeta) {
+      public endSourceSpan: ParseSourceSpan|null, public i18n?: I18nMeta) {}
-    // If the element is empty then the source span should include any closing tag
-    if (children.length === 0 && startSourceSpan && endSourceSpan) {
-      this.sourceSpan = new ParseSourceSpan(sourceSpan.start, endSourceSpan.end);
-    }
-  }
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitElement(this);
   }
@@ -96,7 +91,7 @@ export class Template implements Node {
       public tagName: string, public attributes: TextAttribute[], public inputs: BoundAttribute[],
       public outputs: BoundEvent[], public templateAttrs: (BoundAttribute|TextAttribute)[],
       public children: Node[], public references: Reference[], public variables: Variable[],
-      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan|null,
+      public sourceSpan: ParseSourceSpan, public startSourceSpan: ParseSourceSpan,
       public endSourceSpan: ParseSourceSpan|null, public i18n?: I18nMeta) {}
   visit<Result>(visitor: Visitor<Result>): Result {
     return visitor.visitTemplate(this);

packages/compiler/src/template_parser/template_parser.ts

@@ -244,9 +244,9 @@ class TemplateParseVisitor implements html.Visitor {
   visitText(text: html.Text, parent: ElementContext): any {
     const ngContentIndex = parent.findNgContentIndex(TEXT_CSS_SELECTOR())!;
     const valueNoNgsp = replaceNgsp(text.value);
-    const expr = this._bindingParser.parseInterpolation(valueNoNgsp, text.sourceSpan!);
+    const expr = this._bindingParser.parseInterpolation(valueNoNgsp, text.sourceSpan);
-    return expr ? new t.BoundTextAst(expr, ngContentIndex, text.sourceSpan!) :
+    return expr ? new t.BoundTextAst(expr, ngContentIndex, text.sourceSpan) :
-                  new t.TextAst(valueNoNgsp, ngContentIndex, text.sourceSpan!);
+                  new t.TextAst(valueNoNgsp, ngContentIndex, text.sourceSpan);
   }
 
   visitAttribute(attribute: html.Attribute, context: any): any {
@@ -335,14 +335,14 @@ class TemplateParseVisitor implements html.Visitor {
     const boundDirectivePropNames = new Set<string>();
     const directiveAsts = this._createDirectiveAsts(
         isTemplateElement, element.name, directiveMetas, elementOrDirectiveProps,
-        elementOrDirectiveRefs, element.sourceSpan!, references, boundDirectivePropNames);
+        elementOrDirectiveRefs, element.sourceSpan, references, boundDirectivePropNames);
     const elementProps: t.BoundElementPropertyAst[] = this._createElementPropertyAsts(
         element.name, elementOrDirectiveProps, boundDirectivePropNames);
     const isViewRoot = parent.isTemplateElement || hasInlineTemplates;
 
     const providerContext = new ProviderElementContext(
         this.providerViewContext, parent.providerContext!, isViewRoot, directiveAsts, attrs,
-        references, isTemplateElement, queryStartIndex, element.sourceSpan!);
+        references, isTemplateElement, queryStartIndex, element.sourceSpan);
 
     const children: t.TemplateAst[] = html.visitAll(
         preparsedElement.nonBindable ? NON_BINDABLE_VISITOR : this, element.children,
@@ -360,26 +360,26 @@ class TemplateParseVisitor implements html.Visitor {
     if (preparsedElement.type === PreparsedElementType.NG_CONTENT) {
       // `<ng-content>` element
       if (element.children && !element.children.every(_isEmptyTextNode)) {
-        this._reportError(`<ng-content> element cannot have content.`, element.sourceSpan!);
+        this._reportError(`<ng-content> element cannot have content.`, element.sourceSpan);
       }
 
       parsedElement = new t.NgContentAst(
-          this.ngContentCount++, hasInlineTemplates ? null! : ngContentIndex, element.sourceSpan!);
+          this.ngContentCount++, hasInlineTemplates ? null! : ngContentIndex, element.sourceSpan);
     } else if (isTemplateElement) {
       // `<ng-template>` element
       this._assertAllEventsPublishedByDirectives(directiveAsts, events);
       this._assertNoComponentsNorElementBindingsOnTemplate(
-          directiveAsts, elementProps, element.sourceSpan!);
+          directiveAsts, elementProps, element.sourceSpan);
 
       parsedElement = new t.EmbeddedTemplateAst(
           attrs, events, references, elementVars, providerContext.transformedDirectiveAsts,
           providerContext.transformProviders, providerContext.transformedHasViewContainer,
           providerContext.queryMatches, children, hasInlineTemplates ? null! : ngContentIndex,
-          element.sourceSpan!);
+          element.sourceSpan);
     } else {
       // element other than `<ng-content>` and `<ng-template>`
       this._assertElementExists(matchElement, element);
-      this._assertOnlyOneComponent(directiveAsts, element.sourceSpan!);
+      this._assertOnlyOneComponent(directiveAsts, element.sourceSpan);
 
       const ngContentIndex =
           hasInlineTemplates ? null : parent.findNgContentIndex(projectionSelector);
@@ -397,22 +397,22 @@ class TemplateParseVisitor implements html.Visitor {
       const {directives} = this._parseDirectives(this.selectorMatcher, templateSelector);
       const templateBoundDirectivePropNames = new Set<string>();
       const templateDirectiveAsts = this._createDirectiveAsts(
-          true, elName, directives, templateElementOrDirectiveProps, [], element.sourceSpan!, [],
+          true, elName, directives, templateElementOrDirectiveProps, [], element.sourceSpan, [],
           templateBoundDirectivePropNames);
       const templateElementProps: t.BoundElementPropertyAst[] = this._createElementPropertyAsts(
           elName, templateElementOrDirectiveProps, templateBoundDirectivePropNames);
       this._assertNoComponentsNorElementBindingsOnTemplate(
-          templateDirectiveAsts, templateElementProps, element.sourceSpan!);
+          templateDirectiveAsts, templateElementProps, element.sourceSpan);
       const templateProviderContext = new ProviderElementContext(
           this.providerViewContext, parent.providerContext!, parent.isTemplateElement,
-          templateDirectiveAsts, [], [], true, templateQueryStartIndex, element.sourceSpan!);
+          templateDirectiveAsts, [], [], true, templateQueryStartIndex, element.sourceSpan);
       templateProviderContext.afterElement();
 
       parsedElement = new t.EmbeddedTemplateAst(
           [], [], [], templateElementVars, templateProviderContext.transformedDirectiveAsts,
           templateProviderContext.transformProviders,
           templateProviderContext.transformedHasViewContainer, templateProviderContext.queryMatches,
-          [parsedElement], ngContentIndex, element.sourceSpan!);
+          [parsedElement], ngContentIndex, element.sourceSpan);
     }
 
     return parsedElement;
@@ -707,7 +707,7 @@ class TemplateParseVisitor implements html.Visitor {
         errorMsg +=
             `2. To allow any element add 'NO_ERRORS_SCHEMA' to the '@NgModule.schemas' of this component.`;
       }
-      this._reportError(errorMsg, element.sourceSpan!);
+      this._reportError(errorMsg, element.sourceSpan);
     }
   }
 
@@ -815,7 +815,7 @@ class NonBindableVisitor implements html.Visitor {
 
   visitText(text: html.Text, parent: ElementContext): t.TextAst {
     const ngContentIndex = parent.findNgContentIndex(TEXT_CSS_SELECTOR())!;
-    return new t.TextAst(text.value, ngContentIndex, text.sourceSpan!);
+    return new t.TextAst(text.value, ngContentIndex, text.sourceSpan);
   }
 
   visitExpansion(expansion: html.Expansion, context: any): any {

packages/compiler/test/ml_parser/ast_spec_utils.ts

@@ -42,7 +42,7 @@ class _Humanizer implements html.Visitor {
   visitElement(element: html.Element, context: any): any {
     const res = this._appendContext(element, [html.Element, element.name, this.elDepth++]);
     if (this.includeSourceSpan) {
-      res.push(element.startSourceSpan?.toString() ?? null);
+      res.push(element.startSourceSpan.toString() ?? null);
       res.push(element.endSourceSpan?.toString() ?? null);
     }
     this.result.push(res);
@@ -82,7 +82,7 @@ class _Humanizer implements html.Visitor {
 
   private _appendContext(ast: html.Node, input: any[]): any[] {
     if (!this.includeSourceSpan) return input;
-    input.push(ast.sourceSpan!.toString());
+    input.push(ast.sourceSpan.toString());
     return input;
   }
 }

packages/compiler/test/ml_parser/html_parser_spec.ts

@@ -667,8 +667,8 @@ import {humanizeDom, humanizeDomSourceSpans, humanizeLineColumn} from './ast_spe
         it('should set the start and end source spans', () => {
           const node = <html.Element>parser.parse('<div>a</div>', 'TestComp').rootNodes[0];
 
-          expect(node.startSourceSpan!.start.offset).toEqual(0);
+          expect(node.startSourceSpan.start.offset).toEqual(0);
-          expect(node.startSourceSpan!.end.offset).toEqual(5);
+          expect(node.startSourceSpan.end.offset).toEqual(5);
 
           expect(node.endSourceSpan!.start.offset).toEqual(6);
           expect(node.endSourceSpan!.end.offset).toEqual(12);

packages/compiler/test/ml_parser/icu_ast_expander_spec.ts

@@ -56,10 +56,10 @@ import {humanizeNodes} from './ast_spec_utils';
       const nodes = expand(`{messages.length, plural,=0 {<b>bold</b>}}`).nodes;
 
       const container: html.Element = <html.Element>nodes[0];
-      expect(container.sourceSpan!.start.col).toEqual(0);
+      expect(container.sourceSpan.start.col).toEqual(0);
-      expect(container.sourceSpan!.end.col).toEqual(42);
+      expect(container.sourceSpan.end.col).toEqual(42);
-      expect(container.startSourceSpan!.start.col).toEqual(0);
+      expect(container.startSourceSpan.start.col).toEqual(0);
-      expect(container.startSourceSpan!.end.col).toEqual(42);
+      expect(container.startSourceSpan.end.col).toEqual(42);
       expect(container.endSourceSpan!.start.col).toEqual(0);
       expect(container.endSourceSpan!.end.col).toEqual(42);
 
@@ -68,15 +68,15 @@ import {humanizeNodes} from './ast_spec_utils';
       expect(switchExp.sourceSpan.end.col).toEqual(16);
 
       const template: html.Element = <html.Element>container.children[0];
-      expect(template.sourceSpan!.start.col).toEqual(25);
+      expect(template.sourceSpan.start.col).toEqual(25);
-      expect(template.sourceSpan!.end.col).toEqual(41);
+      expect(template.sourceSpan.end.col).toEqual(41);
 
       const switchCheck = template.attrs[0];
       expect(switchCheck.sourceSpan.start.col).toEqual(25);
       expect(switchCheck.sourceSpan.end.col).toEqual(28);
 
       const b: html.Element = <html.Element>template.children[0];
-      expect(b.sourceSpan!.start.col).toEqual(29);
+      expect(b.sourceSpan.start.col).toEqual(29);
       expect(b.endSourceSpan!.end.col).toEqual(40);
     });
 

packages/compiler/test/template_parser/template_parser_spec.ts

@@ -140,7 +140,7 @@ class TemplateHumanizer implements TemplateAstVisitor {
 
   private _appendSourceSpan(ast: TemplateAst, input: any[]): any[] {
     if (!this.includeSourceSpan) return input;
-    input.push(ast.sourceSpan!.toString());
+    input.push(ast.sourceSpan.toString());
     return input;
   }
 }

packages/language-service/src/completions.ts

@@ -65,7 +65,7 @@ function getBoundedWordSpan(
     // The HTML tag may include `-` (e.g. `app-root`),
     // so use the HtmlAst to get the span before ayazhafiz refactor the code.
     return {
-      start: templateInfo.template.span.start + ast.startSourceSpan!.start.offset + 1,
+      start: templateInfo.template.span.start + ast.startSourceSpan.start.offset + 1,
       length: ast.name.length
     };
   }

packages/localize/src/tools/src/translate/translation_files/translation_parsers/translation_utils.ts

@@ -48,7 +48,7 @@ export function parseInnerRange(element: Element): ParseTreeResult {
  * @param element The element whose inner range we want to compute.
  */
 function getInnerRange(element: Element): LexerRange {
-  const start = element.startSourceSpan!.end;
+  const start = element.startSourceSpan.end;
   const end = element.endSourceSpan!.start;
   return {
     startPos: start.offset,