fix(compiler): handle strings inside bindings that contain binding characters (#39826)

crisbeto · alxhub · commit f5aab2b97289 · 2020-12-10T11:11:22.000-08:00
Currently the compiler treats something like `{{ '{{a}}' }}` as a nested binding and throws an error, because it doesn't account for quotes when it looks for binding characters. These changes add a bit of logic to skip over text inside quotes when parsing. Fixes #39601. PR Close #39826
diff --git a/packages/compiler/src/expression_parser/parser.ts b/packages/compiler/src/expression_parser/parser.ts
@@ -244,10 +244,10 @@ export class Parser {
 
         atInterpolation = true;
       } else {
-        // parse from starting {{ to ending }}
+        // parse from starting {{ to ending }} while ignoring content inside quotes.
         const fullStart = i;
         const exprStart = fullStart + interpStart.length;
-        const exprEnd = input.indexOf(interpEnd, exprStart);
+        const exprEnd = this._getExpressiondEndIndex(input, interpEnd, exprStart);
         if (exprEnd === -1) {
           // Could not find the end of the interpolation; do not parse an expression.
           // Instead we should extend the content on the last raw string.
@@ -340,10 +340,39 @@ export class Parser {
 
     return errLocation.length;
   }
+
+  /**
+   * Finds the index of the end of an interpolation expression
+   * while ignoring comments and quoted content.
+   */
+  private _getExpressiondEndIndex(input: string, expressionEnd: string, start: number): number {
+    let currentQuote: string|null = null;
+    let escapeCount = 0;
+    for (let i = start; i < input.length; i++) {
+      const char = input[i];
+      // Skip the characters inside quotes. Note that we only care about the
+      // outer-most quotes matching up and we need to account for escape characters.
+      if (isQuote(input.charCodeAt(i)) && (currentQuote === null || currentQuote === char) &&
+          escapeCount % 2 === 0) {
+        currentQuote = currentQuote === null ? char : null;
+      } else if (currentQuote === null) {
+        if (input.startsWith(expressionEnd, i)) {
+          return i;
+        }
+        // Nothing else in the expression matters after we've
+        // hit a comment so look directly for the end token.
+        if (input.startsWith('//', i)) {
+          return input.indexOf(expressionEnd, i);
+        }
+      }
+      escapeCount = char === '\\' ? escapeCount + 1 : 0;
+    }
+    return -1;
+  }
 }
 
 export class IvyParser extends Parser {
-  simpleExpressionChecker = IvySimpleExpressionChecker;  //
+  simpleExpressionChecker = IvySimpleExpressionChecker;
 }
 
 /** Describes a stateful context an expression parser is in. */
diff --git a/packages/compiler/test/expression_parser/parser_spec.ts b/packages/compiler/test/expression_parser/parser_spec.ts
@@ -762,6 +762,37 @@ describe('parser', () => {
       expect(ast.expressions[0].name).toEqual('a');
     });
 
+    it('should parse interpolation inside quotes', () => {
+      const ast = parseInterpolation('"{{a}}"')!.ast as Interpolation;
+      expect(ast.strings).toEqual(['"', '"']);
+      expect(ast.expressions.length).toEqual(1);
+      expect(ast.expressions[0].name).toEqual('a');
+    });
+
+    it('should parse interpolation with interpolation characters inside quotes', () => {
+      checkInterpolation('{{"{{a}}"}}', '{{ "{{a}}" }}');
+      checkInterpolation('{{"{{"}}', '{{ "{{" }}');
+      checkInterpolation('{{"}}"}}', '{{ "}}" }}');
+      checkInterpolation('{{"{"}}', '{{ "{" }}');
+      checkInterpolation('{{"}"}}', '{{ "}" }}');
+    });
+
+    it('should parse interpolation with escaped quotes', () => {
+      checkInterpolation(`{{'It\\'s just Angular'}}`, `{{ "It's just Angular" }}`);
+      checkInterpolation(`{{'It\\'s {{ just Angular'}}`, `{{ "It's {{ just Angular" }}`);
+      checkInterpolation(`{{'It\\'s }} just Angular'}}`, `{{ "It's }} just Angular" }}`);
+    });
+
+    it('should parse interpolation with escaped backslashes', () => {
+      checkInterpolation(`{{foo.split('\\\\')}}`, `{{ foo.split("\\") }}`);
+      checkInterpolation(`{{foo.split('\\\\\\\\')}}`, `{{ foo.split("\\\\") }}`);
+      checkInterpolation(`{{foo.split('\\\\\\\\\\\\')}}`, `{{ foo.split("\\\\\\") }}`);
+    });
+
+    it('should not parse interpolation with mismatching quotes', () => {
+      expect(parseInterpolation(`{{ "{{a}}' }}`)).toBeNull();
+    });
+
     it('should parse prefix/suffix with multiple interpolation', () => {
       const originalExp = 'before {{ a }} middle {{ b }} after';
       const ast = parseInterpolation(originalExp)!.ast;
@@ -819,6 +850,10 @@ describe('parser', () => {
       it('should retain // in nested, unterminated strings', () => {
         checkInterpolation(`{{ "a\'b\`" //comment}}`, `{{ "a\'b\`" }}`);
       });
+
+      it('should ignore quotes inside a comment', () => {
+        checkInterpolation(`"{{name // " }}"`, `"{{ name }}"`);
+      });
     });
   });
 
@@ -999,8 +1034,11 @@ function parseSimpleBindingIvy(
 }
 
 function checkInterpolation(exp: string, expected?: string) {
-  const ast = parseInterpolation(exp)!;
+  const ast = parseInterpolation(exp);
   if (expected == null) expected = exp;
+  if (ast === null) {
+    throw Error(`Failed to parse expression "${exp}"`);
+  }
   expect(unparse(ast)).toEqual(expected);
   validate(ast);
 }
diff --git a/packages/compiler/test/template_parser/template_parser_spec.ts b/packages/compiler/test/template_parser/template_parser_spec.ts
@@ -540,6 +540,54 @@ describe('TemplateParser', () => {
       expect(humanizeTplAst(parse('{{a}}', []))).toEqual([[BoundTextAst, '{{ a }}']]);
     });
 
+    it('should parse bound text nodes inside quotes', () => {
+      expect(humanizeTplAst(parse('"{{a}}"', []))).toEqual([[BoundTextAst, '"{{ a }}"']]);
+    });
+
+    it('should parse bound text nodes with interpolations inside quotes', () => {
+      expect(humanizeTplAst(parse('{{ "{{a}}" }}', []))).toEqual([[BoundTextAst, '{{ "{{a}}" }}']]);
+      expect(humanizeTplAst(parse('{{"{{"}}', []))).toEqual([[BoundTextAst, '{{ "{{" }}']]);
+      expect(humanizeTplAst(parse('{{"}}"}}', []))).toEqual([[BoundTextAst, '{{ "}}" }}']]);
+      expect(humanizeTplAst(parse('{{"{"}}', []))).toEqual([[BoundTextAst, '{{ "{" }}']]);
+      expect(humanizeTplAst(parse('{{"}"}}', []))).toEqual([[BoundTextAst, '{{ "}" }}']]);
+    });
+
+    it('should parse bound text nodes with escaped quotes', () => {
+      expect(humanizeTplAst(parse(`{{'It\\'s just Angular'}}`, []))).toEqual([
+        [BoundTextAst, `{{ "It's just Angular" }}`]
+      ]);
+
+      expect(humanizeTplAst(parse(`{{'It\\'s {{ just Angular'}}`, []))).toEqual([
+        [BoundTextAst, `{{ "It's {{ just Angular" }}`]
+      ]);
+
+      expect(humanizeTplAst(parse(`{{'It\\'s }} just Angular'}}`, []))).toEqual([
+        [BoundTextAst, `{{ "It's }} just Angular" }}`]
+      ]);
+    });
+
+    it('should not parse bound text nodes with mismatching quotes', () => {
+      expect(humanizeTplAst(parse(`{{ "{{a}}' }}`, []))).toEqual([[TextAst, `{{ "{{a}}' }}`]]);
+    });
+
+    it('should parse interpolation with escaped backslashes', () => {
+      expect(humanizeTplAst(parse(`{{foo.split('\\\\')}}`, []))).toEqual([
+        [BoundTextAst, `{{ foo.split("\\") }}`]
+      ]);
+      expect(humanizeTplAst(parse(`{{foo.split('\\\\\\\\')}}`, []))).toEqual([
+        [BoundTextAst, `{{ foo.split("\\\\") }}`]
+      ]);
+      expect(humanizeTplAst(parse(`{{foo.split('\\\\\\\\\\\\')}}`, []))).toEqual([
+        [BoundTextAst, `{{ foo.split("\\\\\\") }}`]
+      ]);
+    });
+
+    it('should ignore quotes inside a comment', () => {
+      expect(humanizeTplAst(parse(`"{{name // " }}"`, []))).toEqual([
+        [BoundTextAst, `"{{ name }}"`]
+      ]);
+    });
+
     it('should parse with custom interpolation config',
        inject([TemplateParser], (parser: TemplateParser) => {
          const component = CompileDirectiveMetadata.create({
diff --git a/packages/core/test/acceptance/text_spec.ts b/packages/core/test/acceptance/text_spec.ts
@@ -171,4 +171,18 @@ describe('text instructions', () => {
     // `Symbol(hello)_p.sc8s398cplk`, whereas the native one is `Symbol(hello)`.
     expect(fixture.nativeElement.textContent).toContain('Symbol(hello)');
   });
+
+  it('should handle binding syntax used inside quoted text', () => {
+    @Component({
+      template: `{{'Interpolations look like {{this}}'}}`,
+    })
+    class App {
+    }
+
+    TestBed.configureTestingModule({declarations: [App]});
+    const fixture = TestBed.createComponent(App);
+    fixture.detectChanges();
+
+    expect(fixture.nativeElement.textContent).toBe('Interpolations look like {{this}}');
+  });
 });
