From f2cf86250344f692cbdce55f88a0977d2a5c20e5 Mon Sep 17 00:00:00 2001
From: Younes ENNAJI <younes.ennaji.pro@gmail.com>
Date: Wed, 12 Nov 2025 00:27:57 +0100
Subject: [PATCH] [Yaml] Fix parsing of unquoted multiline scalars with
 comments or blank lines

---
 src/Symfony/Component/Yaml/Parser.php         |  9 +++
 .../Component/Yaml/Tests/ParserTest.php       | 67 +++++++++++++++++++
 2 files changed, 76 insertions(+)

diff --git a/src/Symfony/Component/Yaml/Parser.php b/src/Symfony/Component/Yaml/Parser.php
index 40702ed639e7a..ebfd27d432404 100644
--- a/src/Symfony/Component/Yaml/Parser.php
+++ b/src/Symfony/Component/Yaml/Parser.php
@@ -762,6 +762,11 @@ private function parseValue(string $value, int $flags, string $context): mixed
                     $lines = [];
 
                     while ($this->moveToNextLine()) {
+                        if ($this->isCurrentLineBlank()) {
+                            $lines[] = '';
+                            continue;
+                        }
+
                         // unquoted strings end before the first unindented line
                         if (0 === $this->getCurrentLineIndentation()) {
                             $this->moveToPreviousLine();
@@ -769,6 +774,10 @@ private function parseValue(string $value, int $flags, string $context): mixed
                             break;
                         }
 
+                        if ($this->isCurrentLineComment()) {
+                            continue;
+                        }
+
                         $lines[] = trim($this->currentLine);
                     }
 
diff --git a/src/Symfony/Component/Yaml/Tests/ParserTest.php b/src/Symfony/Component/Yaml/Tests/ParserTest.php
index ebf032795fcec..b523612a6ed93 100644
--- a/src/Symfony/Component/Yaml/Tests/ParserTest.php
+++ b/src/Symfony/Component/Yaml/Tests/ParserTest.php
@@ -1751,6 +1751,73 @@ public function testParseMultiLineUnquotedString()
         $this->assertSame(['foo' => 'bar baz foobar foo', 'bar' => 'baz'], $this->parser->parse($yaml));
     }
 
+    /**
+     * @dataProvider getUnquotedMultilineScalarIgnoresCommentsData
+     */
+    public function testUnquotedMultilineScalarIgnoresComments(string $yaml, array $expected)
+    {
+        $this->assertSame($expected, $this->parser->parse($yaml));
+    }
+
+    public static function getUnquotedMultilineScalarIgnoresCommentsData()
+    {
+        yield 'comments interspersed' => [
+            <<<YAML
+                key: unquoted
+                  # this comment should be ignored
+                  next line
+                  # another comment
+                  final line
+                another_key: works
+                YAML,
+            [
+                'key' => 'unquoted next line final line',
+                'another_key' => 'works',
+            ],
+        ];
+
+        yield 'only comments' => [
+            <<<YAML
+                key: unquoted
+                  # this comment should be ignored
+                  # another comment
+                another_key: works
+                YAML,
+            [
+                'key' => 'unquoted',
+                'another_key' => 'works',
+            ],
+        ];
+
+        yield 'blank lines and comments' => [
+            <<<YAML
+                key: unquoted
+                  next line
+
+                  # this comment should be ignored
+                  final line
+                another_key: works
+                YAML,
+            [
+                'key' => "unquoted next line\nfinal line",
+                'another_key' => 'works',
+            ],
+        ];
+
+        yield 'comment at end' => [
+            <<<YAML
+                key: unquoted
+                  next line
+                  # comment at end
+                another_key: works
+                YAML,
+            [
+                'key' => 'unquoted next line',
+                'another_key' => 'works',
+            ],
+        ];
+    }
+
     /**
      * @dataProvider unquotedStringWithTrailingComment
      */