[HttpClient] fix sending Content-Length/Type for POST

Author: nicolas-grekas

CurlHttpClient.php

@@ -246,7 +246,7 @@ public function request(string $method, string $url, array $options = []): Respo
         } elseif ('' !== $body || 'POST' === $method || $hasContentLength) {
             $curlopts[\CURLOPT_POSTFIELDS] = $body;
 
-            if ('' === $body && !isset($options['normalized_headers']['content-type'])) {
+            if ('' === $body && 'POST' !== $method && !isset($options['normalized_headers']['content-type'])) {
                 $curlopts[\CURLOPT_HTTPHEADER][] = 'Content-Type:';
             }
         }

NativeHttpClient.php

@@ -82,7 +82,10 @@ public function request(string $method, string $url, array $options = []): Respo
 
         $options['body'] = self::getBodyAsString($options['body']);
 
-        if ('' !== $options['body'] && !isset($options['normalized_headers']['content-type'])) {
+        if ('' === $options['body'] && 'POST' === $method && !isset($options['normalized_headers']['content-length'])) {
+            $options['headers'][] = 'Content-Length: 0';
+        }
+        if (('' !== $options['body'] || 'POST' === $method) && !isset($options['normalized_headers']['content-type'])) {
             $options['headers'][] = 'Content-Type: application/x-www-form-urlencoded';
         }
 

Tests/HttpClientTestCase.php

@@ -208,10 +208,11 @@ public function testRedirectAfterPost()
         $client = $this->getHttpClient(__FUNCTION__);
 
         $response = $client->request('POST', 'http://localhost:8057/302/relative', [
-            'body' => 'abc',
+            'body' => '',
         ]);
 
         $this->assertSame(200, $response->getStatusCode());
+        $this->assertStringContainsString("\r\nContent-Length: 0", $response->getInfo('debug'));
     }
 
     public function testEmptyPut()