[HttpClient] Fix overriding default options with null

Author: nicolas-grekas

HttpClientTrait.php

@@ -187,11 +187,7 @@ private static function mergeDefaultOptions(array $options, array $defaultOption
         // Option "query" is never inherited from defaults
         $options['query'] = $options['query'] ?? [];
 
-        foreach ($defaultOptions as $k => $v) {
-            if ('normalized_headers' !== $k && !isset($options[$k])) {
-                $options[$k] = $v;
-            }
-        }
+        $options += $defaultOptions;
 
         if (isset($defaultOptions['extra'])) {
             $options['extra'] += $defaultOptions['extra'];

Tests/MockHttpClientTest.php

@@ -14,6 +14,7 @@
 use Symfony\Component\HttpClient\Chunk\DataChunk;
 use Symfony\Component\HttpClient\Chunk\ErrorChunk;
 use Symfony\Component\HttpClient\Chunk\FirstChunk;
+use Symfony\Component\HttpClient\Exception\InvalidArgumentException;
 use Symfony\Component\HttpClient\Exception\TransportException;
 use Symfony\Component\HttpClient\MockHttpClient;
 use Symfony\Component\HttpClient\NativeHttpClient;
@@ -150,6 +151,15 @@ public function testThrowExceptionInBodyGenerator()
         $this->assertSame('bar ccc', $chunks[2]->getError());
     }
 
+    public function testMergeDefaultOptions()
+    {
+        $mockHttpClient = new MockHttpClient(null, 'https://example.com');
+
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URL: scheme is missing');
+        $mockHttpClient->request('GET', '/foo', ['base_uri' => null]);
+    }
+
     protected function getHttpClient(string $testCase): HttpClientInterface
     {
         $responses = [];