diff --git a/composer.json b/composer.json
index 008375cfbe7ec..98ff6c774ce12 100644
--- a/composer.json
+++ b/composer.json
@@ -183,7 +183,8 @@
             "Symfony\\Bridge\\PsrHttpMessage\\": "src/Symfony/Bridge/PsrHttpMessage/",
             "Symfony\\Bridge\\Twig\\": "src/Symfony/Bridge/Twig/",
             "Symfony\\Bundle\\": "src/Symfony/Bundle/",
-            "Symfony\\Component\\": "src/Symfony/Component/"
+            "Symfony\\Component\\": "src/Symfony/Component/",
+            "Symfony\\Runtime\\Symfony\\Component\\": "src/Symfony/Component/Runtime/Internal/"
         },
         "files": [
             "src/Symfony/Component/String/Resources/functions.php"
@@ -192,7 +193,8 @@
             "src/Symfony/Component/Cache/Traits/ValueWrapper.php"
         ],
         "exclude-from-classmap": [
-            "**/Tests/"
+            "**/Tests/",
+            "**/bin/"
         ]
     },
     "autoload-dev": {
diff --git a/src/Symfony/Bridge/PhpUnit/composer.json b/src/Symfony/Bridge/PhpUnit/composer.json
index 3fa0f8dc517da..1283dfe33a9b0 100644
--- a/src/Symfony/Bridge/PhpUnit/composer.json
+++ b/src/Symfony/Bridge/PhpUnit/composer.json
@@ -32,7 +32,8 @@
         "files": [ "bootstrap.php" ],
         "psr-4": { "Symfony\\Bridge\\PhpUnit\\": "" },
         "exclude-from-classmap": [
-            "/Tests/"
+            "/Tests/",
+            "/bin/"
         ]
     },
     "bin": [
diff --git a/src/Symfony/Component/Mime/Part/TextPart.php b/src/Symfony/Component/Mime/Part/TextPart.php
index a13300955e36c..1054c25e46f9b 100644
--- a/src/Symfony/Component/Mime/Part/TextPart.php
+++ b/src/Symfony/Component/Mime/Part/TextPart.php
@@ -123,7 +123,11 @@ public function getName(): ?string
     public function getBody(): string
     {
         if ($this->body instanceof File) {
-            return file_get_contents($this->body->getPath());
+            if (false === $ret = @file_get_contents($this->body->getPath())) {
+                throw new InvalidArgumentException(error_get_last()['message']);
+            }
+
+            return $ret;
         }
 
         if (null === $this->seekable) {
diff --git a/src/Symfony/Component/Mime/Tests/Part/TextPartTest.php b/src/Symfony/Component/Mime/Tests/Part/TextPartTest.php
index 905349e670048..ae1a5921ecc1e 100644
--- a/src/Symfony/Component/Mime/Tests/Part/TextPartTest.php
+++ b/src/Symfony/Component/Mime/Tests/Part/TextPartTest.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\Mime\Tests\Part;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Mime\Exception\InvalidArgumentException;
 use Symfony\Component\Mime\Header\Headers;
 use Symfony\Component\Mime\Header\ParameterizedHeader;
 use Symfony\Component\Mime\Header\UnstructuredHeader;
@@ -55,6 +56,16 @@ public function testConstructorWithFile()
         $this->assertSame('content', implode('', iterator_to_array($p->bodyToIterable())));
     }
 
+    public function testConstructorWithUnknownFile()
+    {
+        $p = new TextPart(new File(\dirname(__DIR__).'/Fixtures/unknown.txt'));
+
+        // Exception should be thrown only when the body is accessed
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessageMatches('{Failed to open stream}');
+        $p->getBody();
+    }
+
     public function testConstructorWithNonStringOrResource()
     {
         $this->expectException(\TypeError::class);
diff --git a/src/Symfony/Component/Scheduler/Schedule.php b/src/Symfony/Component/Scheduler/Schedule.php
index 4ccd88ff7a6e9..bd413892bc671 100644
--- a/src/Symfony/Component/Scheduler/Schedule.php
+++ b/src/Symfony/Component/Scheduler/Schedule.php
@@ -141,6 +141,10 @@ public function getSchedule(): static
 
     public function before(callable $listener, int $priority = 0): static
     {
+        if (!$this->dispatcher) {
+            throw new LogicException(sprintf('To register a listener with "%s()", you need to set an event dispatcher on the Schedule.', __METHOD__));
+        }
+
         $this->dispatcher->addListener(PreRunEvent::class, $listener, $priority);
 
         return $this;
@@ -148,6 +152,10 @@ public function before(callable $listener, int $priority = 0): static
 
     public function after(callable $listener, int $priority = 0): static
     {
+        if (!$this->dispatcher) {
+            throw new LogicException(sprintf('To register a listener with "%s()", you need to set an event dispatcher on the Schedule.', __METHOD__));
+        }
+
         $this->dispatcher->addListener(PostRunEvent::class, $listener, $priority);
 
         return $this;
@@ -155,6 +163,10 @@ public function after(callable $listener, int $priority = 0): static
 
     public function onFailure(callable $listener, int $priority = 0): static
     {
+        if (!$this->dispatcher) {
+            throw new LogicException(sprintf('To register a listener with "%s()", you need to set an event dispatcher on the Schedule.', __METHOD__));
+        }
+
         $this->dispatcher->addListener(FailureEvent::class, $listener, $priority);
 
         return $this;
diff --git a/src/Symfony/Component/Validator/composer.json b/src/Symfony/Component/Validator/composer.json
index 4f55dd2d1f827..1076a74854453 100644
--- a/src/Symfony/Component/Validator/composer.json
+++ b/src/Symfony/Component/Validator/composer.json
@@ -54,7 +54,8 @@
     "autoload": {
         "psr-4": { "Symfony\\Component\\Validator\\": "" },
         "exclude-from-classmap": [
-            "/Tests/"
+            "/Tests/",
+            "/Resources/bin/"
         ]
     },
     "minimum-stability": "dev"