Updated attachment download to check OB before cleaning it

Call to `ob_end_clean` would error if the environment did not use the
PHP `output_buffering` option. This adds an additional check and updates
the comment to be more specific to the exact scenario of the condition.
Tested with output_buffering=Off and output_buffering=4096

Closes #3415

diff --git a/app/Http/Controllers/Controller.php b/app/Http/Controllers/Controller.php
index c00ac938bdae2b56586d4d97bc74820cd5b7bbd5..5b2221fc1235c412ae00c57971d77425ec8b737c 100644 (file)
--- a/app/Http/Controllers/Controller.php
+++ b/app/Http/Controllers/Controller.php
@@ -127,9 +127,11 @@ abstract class Controller extends BaseController
     protected function streamedDownloadResponse($stream, string $fileName): StreamedResponse
     {
         return response()->stream(function () use ($stream) {
-            // End & flush the output buffer otherwise we still seem to use memory.
+
+            // End & flush the output buffer, if we're in one, otherwise we still use memory.
+            // Output buffer may or may not exist depending on PHP `output_buffering` setting.
             // Ignore in testing since output buffers are used to gather a response.
-            if (!app()->runningUnitTests()) {
+            if (!empty(ob_get_status()) && !app()->runningUnitTests()) {
                 ob_end_clean();
             }