bug symfony#59763 [HttpClient] Don't send any default content-type when the body is empty (nicolas-grekas)

This PR was merged into the 6.4 branch.

Discussion
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[HttpClient] Don't send any default content-type when the body is empty

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Issues        | -
| License       | MIT

Issue was introduced in symfony#49911

Commits
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4a475e0 [HttpClient] Don't send any default content-type when the body is empty

Author: nicolas-grekas

src/Symfony/Component/HttpClient/HttpClientTrait.php

@@ -356,9 +356,11 @@ private static function normalizeBody($body, array &$normalizedHeaders = [])
                 }
             });
 
-            $body = http_build_query($body, '', '&');
+            if ('' === $body = http_build_query($body, '', '&')) {
+                return '';
+            }
 
-            if ('' === $body || !$streams && !str_contains($normalizedHeaders['content-type'][0] ?? '', 'multipart/form-data')) {
+            if (!$streams && !str_contains($normalizedHeaders['content-type'][0] ?? '', 'multipart/form-data')) {
                 if (!str_contains($normalizedHeaders['content-type'][0] ?? '', 'application/x-www-form-urlencoded')) {
                     $normalizedHeaders['content-type'] = ['Content-Type: application/x-www-form-urlencoded'];
                 }