From 736b1f9fd4d06934f32d5e94f6eeefb8d4edee99 Mon Sep 17 00:00:00 2001
From: Andrew Scott <atscott@google.com>
Date: Mon, 1 Mar 2021 12:41:40 -0800
Subject: [PATCH] fix(compiler): recover from an incomplete open tag at the end
 of a file (#41054)

The compiler's parsing code has logic to recover from incomplete open
tags (i.e. `<div`) but the recovery logic does not handle when the
incomplete tag is terminated by an EOF. This commit updates the logic to
allow for the EOF character to be interpreted as the end of the tag open
so that the parser can continue processing. It will then fail to find
the end tag and recover by marking the open tag as incomplete.

Part of https://github.com/angular/vscode-ng-language-service/issues/1140

PR Close #41054
---
 packages/compiler/src/ml_parser/lexer.ts       | 5 +++--
 packages/compiler/test/ml_parser/lexer_spec.ts | 7 +++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/packages/compiler/src/ml_parser/lexer.ts b/packages/compiler/src/ml_parser/lexer.ts
index 09d976a7b5..6864d5a550 100644
--- a/packages/compiler/src/ml_parser/lexer.ts
+++ b/packages/compiler/src/ml_parser/lexer.ts
@@ -523,7 +523,7 @@ class _Tokenizer {
       tagName = openTagToken.parts[1];
       this._attemptCharCodeUntilFn(isNotWhitespace);
       while (this._cursor.peek() !== chars.$SLASH && this._cursor.peek() !== chars.$GT &&
-             this._cursor.peek() !== chars.$LT) {
+             this._cursor.peek() !== chars.$LT && this._cursor.peek() !== chars.$EOF) {
         this._consumeAttributeName();
         this._attemptCharCodeUntilFn(isNotWhitespace);
         if (this._attemptCharCode(chars.$EQ)) {
@@ -774,7 +774,8 @@ function isNotWhitespace(code: number): boolean {
 
 function isNameEnd(code: number): boolean {
   return chars.isWhitespace(code) || code === chars.$GT || code === chars.$LT ||
-      code === chars.$SLASH || code === chars.$SQ || code === chars.$DQ || code === chars.$EQ;
+      code === chars.$SLASH || code === chars.$SQ || code === chars.$DQ || code === chars.$EQ ||
+      code === chars.$EOF;
 }
 
 function isPrefixEnd(code: number): boolean {
diff --git a/packages/compiler/test/ml_parser/lexer_spec.ts b/packages/compiler/test/ml_parser/lexer_spec.ts
index 179b49f01d..7d451b52ea 100644
--- a/packages/compiler/test/ml_parser/lexer_spec.ts
+++ b/packages/compiler/test/ml_parser/lexer_spec.ts
@@ -234,6 +234,13 @@ import {ParseLocation, ParseSourceFile, ParseSourceSpan} from '../../src/parse_u
       });
 
       describe('tags', () => {
+        it('terminated with EOF', () => {
+          expect(tokenizeAndHumanizeSourceSpans('<div')).toEqual([
+            [lex.TokenType.INCOMPLETE_TAG_OPEN, '<div'],
+            [lex.TokenType.EOF, ''],
+          ]);
+        });
+
         it('after tag name', () => {
           expect(tokenizeAndHumanizeSourceSpans('<div<span><div</span>')).toEqual([
             [lex.TokenType.INCOMPLETE_TAG_OPEN, '<div'],