symfony
diff --git a/‎src/Symfony/Component/Yaml/Parser.php‎
Lines changed: 5 additions & 1 deletion b/‎src/Symfony/Component/Yaml/Parser.php‎
Lines changed: 5 additions & 1 deletion
diff --git a/‎src/Symfony/Component/Yaml/Tests/ParserTest.php‎
Lines changed: 46 additions & 0 deletions b/‎src/Symfony/Component/Yaml/Tests/ParserTest.php‎
Lines changed: 46 additions & 0 deletions
@@ -402,7 +402,7 @@ private function doParse($value, $flags)
                     throw new ParseException('Multiple documents are not supported.', $this->currentLineNb + 1, $this->currentLine, $this->filename);
                 }
 
-                if (isset($this->currentLine[1]) && '?' === $this->currentLine[0] && ' ' === $this->currentLine[1]) {
+                if ($deprecatedUsage = (isset($this->currentLine[1]) && '?' === $this->currentLine[0] && ' ' === $this->currentLine[1])) {
                     @trigger_error($this->getDeprecationMessage('Starting an unquoted string with a question mark followed by a space is deprecated since Symfony 3.3 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0.'), E_USER_DEPRECATED);
                 }
 
@@ -427,6 +427,10 @@ private function doParse($value, $flags)
                     $value = '';
 
                     foreach ($this->lines as $line) {
+                        // If the indentation is not consistent at offset 0, it is to be considered as a ParseError
+                        if (0 === $this->offset && !$deprecatedUsage && isset($line[0]) && ' ' === $line[0]) {
+                            throw new ParseException('Unable to parse.', $this->getRealCurrentLineNb() + 1, $this->currentLine, $this->filename);
+                        }
                         if ('' === trim($line)) {
                             $value .= "\n";
                         } elseif (!$previousLineWasNewline && !$previousLineWasTerminatedWithBackslash) {
 
@@ -812,6 +812,41 @@ public function testNonStringFollowedByCommentEmbeddedInMapping()
         $this->assertSame($expected, $this->parser->parse($yaml));
     }
 
+    public function getParseExceptionNotAffectedMultiLineStringLastResortParsing()
+    {
+        $tests = array();
+
+        $yaml = <<<'EOT'
+a
+    b:
+EOT;
+        $tests['parse error on first line'] = array($yaml);
+
+        $yaml = <<<'EOT'
+a
+
+b<
8000
/div>
+    c:
+EOT;
+        $tests['parse error due to inconsistent indentation'] = array($yaml);
+
+        $yaml = <<<'EOT'
+ &  *  !  |  >  '  "  %  @  ` #, { asd a;sdasd }-@^qw3
+EOT;
+        $tests['symfony/symfony/issues/22967#issuecomment-322067742'] = array($yaml);
+
+        return $tests;
+    }
+
+    /**
+     * @dataProvider getParseExceptionNotAffectedMultiLineStringLastResortParsing
+     * @expectedException \Symfony\Component\Yaml\Exception\ParseException
+     */
+    public function testParseExceptionNotAffectedByMultiLineStringLastResortParsing($yaml)
+    {
+        $this->parser->parse($yaml);
+    }
+
     public function testMultiLineStringLastResortParsing()
     {
         $yaml = <<<'EOT'
@@ -825,6 +860,17 @@ public function testMultiLineStringLastResortParsing()
         );
 
         $this->assertSame($expected, $this->parser->parse($yaml));
+
+        $yaml = <<<'EOT'
+a:
+    b
+       c
+EOT;
+        $expected = array(
+            'a' => 'b c',
+        );
+
+        $this->assertSame($expected, $this->parser->parse($yaml));
     }
 
     /**