bug #36743 [Yaml] Fix escaped quotes in quoted multi-line string (ossinkine)

This PR was merged into the 3.4 branch.

Discussion
----------

[Yaml] Fix escaped quotes in quoted multi-line string

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| License       | MIT

This PR continues symfony/symfony#19304

This PR fixes incorrect parsing quoted multi-line string which contain escaped quotes, see tests

Commits
-------

2e99caacaf [Yaml] Fix escaped quotes in quoted multi-line string

Author: fabpot

Parser.php

@@ -757,7 +757,8 @@ private function parseValue($value, $flags, $context)
                 $lines[] = trim($this->currentLine);
 
                 // quoted string values end with a line that is terminated with the quotation character
-                if ('' !== $this->currentLine && substr($this->currentLine, -1) === $quotation) {
+                $escapedLine = str_replace(['\\\\', '\\"'], '', $this->currentLine);
+                if ('' !== $escapedLine && substr($escapedLine, -1) === $quotation) {
                     break;
                 }
             }

Tests/ParserTest.php

@@ -1650,6 +1650,33 @@ public function testBlankLinesInQuotedMultiLineString()
         $this->assertSame($expected, $this->parser->parse($yaml));
     }
 
+    public function testEscapedQuoteInQuotedMultiLineString()
+    {
+        $yaml = <<<YAML
+foobar: "foo
+    \\"bar\\"
+    baz"
+YAML;
+        $expected = [
+            'foobar' => 'foo "bar" baz',
+        ];
+
+        $this->assertSame($expected, $this->parser->parse($yaml));
+    }
+
+    public function testBackslashInQuotedMultiLineString()
+    {
+        $yaml = <<<YAML
+foobar: "foo
+    bar\\\\"
+YAML;
+        $expected = [
+            'foobar' => 'foo bar\\',
+        ];
+
+        $this->assertSame($expected, $this->parser->parse($yaml));
+    }
+
     public function testParseMultiLineUnquotedString()
     {
         $yaml = <<<EOT