minor #60377 [HttpFoundation] Emit PHP warning when Response::sendHeaders() is called while output has already been sent (ivo95v)

fabpot · fabpot · commit cf554e1be633 · 2025-05-10T11:49:00.000+02:00
This PR was merged into the 7.3 branch. Discussion ---------- [HttpFoundation] Emit PHP warning when `Response::sendHeaders()` is called while output has already been sent | Q | A | ------------- | --- | Branch? | 7.3 | Bug fix? | no | New feature? | no | Deprecations? | no | Issues | - | License | MIT Description: When Symfony attempts to send HTTP headers via the sendHeaders() method, it silently aborts if headers have already been sent (e.g., due to whitespace before the <?php tag). I spent an entire day debugging this issue and discovered that the problem was caused by an unintended whitespace before a PHP opening tag. To avoid this kind of silent failure and make future debugging easier, I decided to add an error log. Commits ------- a69cf15 [HttpFoundation] Emit PHP warning when Response::sendHeaders() while output has already been sent
diff --git a/src/Symfony/Component/HttpFoundation/Response.php b/src/Symfony/Component/HttpFoundation/Response.php
@@ -317,6 +317,11 @@ public function sendHeaders(?int $statusCode = null): static
     {
         // headers have already been sent by the developer
         if (headers_sent()) {
+            if (!\in_array(\PHP_SAPI, ['cli', 'phpdbg', 'embed'], true)) {
+                $statusCode ??= $this->statusCode;
+                header(\sprintf('HTTP/%s %s %s', $this->version, $statusCode, $this->statusText), true, $statusCode);
+            }
+
             return $this;
         }
 

Original file line number	Diff line number	Diff line change
`@@ -317,6 +317,11 @@ public function sendHeaders(?int $statusCode = null): static`
`317`	`317`	`{`
`318`	`318`	`// headers have already been sent by the developer`
`319`	`319`	`if (headers_sent()) {`
	`320`	`+ if (!\in_array(\PHP_SAPI, ['cli', 'phpdbg', 'embed'], true)) {`
	`321`	`+ $statusCode ??= $this->statusCode;`
	`322`	`+ header(\sprintf('HTTP/%s %s %s', $this->version, $statusCode, $this->statusText), true, $statusCode);`
	`323`	`+ }`
	`324`	`+`
`320`	`325`	`return $this;`
`321`	`326`	`}`
`322`	`327`