minor #30480 [Mime] Use "yield from" when possible (fabpot)

This PR was merged into the 4.3-dev branch.

Discussion
----------

[Mime] Use "yield from" when possible

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | no <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

Commits
-------

df1b627417 [Mime] used yield-from when possible

src/Symfony/Component/Mime/Message.php

@@ -122,9 +122,7 @@ class Message extends RawMessage
         }
 
         yield $this->getPreparedHeaders()->toString();
-        foreach ($body->toIterable() as $chunk) {
+        yield from $body->toIterable();
-            yield $chunk;
-        }
     }
 
     private function generateMessageId(string $email): string

src/Symfony/Component/Mime/Part/AbstractMultipartPart.php

@@ -81,9 +81,7 @@ abstract class AbstractMultipartPart extends AbstractPart
 
         foreach ($parts as $part) {
             yield '--'.$this->getBoundary()."\r\n";
-            foreach ($part->toIterable() as $chunk) {
+            yield from $part->toIterable();
-                yield $chunk;
-            }
             yield "\r\n";
         }
         yield '--'.$this->getBoundary()."--\r\n";

src/Symfony/Component/Mime/Part/AbstractPart.php

@@ -49,9 +49,7 @@ abstract class AbstractPart
     {
         yield $this->getPreparedHeaders()->toString();
         yield "\r\n";
-        foreach ($this->bodyToIterable() as $chunk) {
+        yield from $this->bodyToIterable();
-            yield $chunk;
-        }
     }
 
     abstract public function bodyToString(): string;

src/Symfony/Component/Mime/Part/TextPart.php

@@ -118,9 +118,7 @@ class TextPart extends AbstractPart
             if (stream_get_meta_data($this->body)['seekable'] ?? false) {
                 rewind($this->body);
             }
-            foreach ($this->getEncoder()->encodeByteStream($this->body) as $chunk) {
+            yield from $this->getEncoder()->encodeByteStream($this->body);
-                yield $chunk;
-            }
         } else {
             yield $this->getEncoder()->encodeString($this->body);
         }

src/Symfony/Component/Mime/RawMessage.php

@@ -34,7 +34,7 @@ class RawMessage
             return $this->message;
         }
 
-        return $this->message = implode('', iterator_to_array($this->message));
+        return $this->message = implode('', iterator_to_array($this->message, false));
     }
 
     public function toIterable(): iterable

src/Symfony/Component/Mime/Tests/MessageTest.php

@@ -131,7 +131,7 @@ Content-Transfer-Encoding: quoted-printable
 
 EOF;
         $this->assertStringMatchesFormat($expected, str_replace("\r\n", "\n", $message->toString()));
-        $this->assertStringMatchesFormat($expected, str_replace("\r\n", "\n", implode('', iterator_to_array($message->toIterable()))));
+        $this->assertStringMatchesFormat($expected, str_replace("\r\n", "\n", implode('', iterator_to_array($message->toIterable(), false))));
 
         $message = new Message(null, new TextPart('content'));
         $message->getHeaders()->addMailboxListHeader('From', ['fabien@symfony.com']);
@@ -146,6 +146,6 @@ Content-Transfer-Encoding: quoted-printable
 content
 EOF;
         $this->assertStringMatchesFormat($expected, str_replace("\r\n", "\n", $message->toString()));
-        $this->assertStringMatchesFormat($expected, str_replace("\r\n", "\n", implode('', iterator_to_array($message->toIterable()))));
+        $this->assertStringMatchesFormat($expected, str_replace("\r\n", "\n", implode('', iterator_to_array($message->toIterable(), false))));
     }
 }