RuntimeException: Failed to start the session because headers have already been sent by ... rest_api_authentication.install

Hi there, I just tried to reproduce the error using the steps you mentioned but everything seemed to be working fine on my end. Can you please install the latest version of the module(2.0.5) and test again? Please let me know whether the issue persists

Doing a fresh install of the module both via Composer and manual. I receive the same error. I uninstalled the module, installed a fresh copy of Drupal and installed this module by itself -- same error.

Uncaught PHP Exception RuntimeException: "Failed to start the session because headers have already been sent by "/home/www/modules/rest_api_authentication/rest_api_authentication.install" at line 1." at /home/www/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php line 152

RuntimeException: Failed to start the session because headers have already been sent by "/home/www/modules/rest_api_authentication/rest_api_authentication.install" at line 1. in /home/www/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php on line 152 #0 /home/www/core/lib/Drupal/Core/Session/SessionManager.php(162): Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->start()
#1 /home/www/core/lib/Drupal/Core/Session/SessionManager.php(193): Drupal\Core\Session\SessionManager->startNow()
#2 /home/www/vendor/symfony/http-foundation/Session/Session.php(191): Drupal\Core\Session\SessionManager->save()
#3 /home/www/core/lib/Drupal/Core/StackMiddleware/Session.php(61): Symfony\Component\HttpFoundation\Session\Session->save()
#4 /home/www/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(48): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#5 /home/www/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#6 /home/www/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\page_cache\StackMiddleware\PageCache->pass(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#7 /home/www/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(48): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#8 /home/www/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(51): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#9 /home/www/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#10 /home/www/core/lib/Drupal/Core/DrupalKernel.php(713): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#11 /home/www/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request))
#12 {main}

Just another note, Drupal believes the modules is indeed installed but the configuration pages are blank and return 404 errors.

And to clarify, this is on the latest version 2.0.6.

Hi @Shane, thanks for sharing the error trace. I just checked the code and it seems like there is an additional line before the php tag for the .install file. As I am not able to reproduce the issue on my environment, can you please test the latest module (version: 2.0.7) and let me know if the issue still persists.
Thanks in advance.

Hi,

there is the same issue with the newest version 2.0.8. Blank line before opening <?php tags in install file. Removing this line solves the problem.

Hi @skutova.mir, thank you for pointing out the issue. I have made the said fixes and released an update of the module. As I am not able to reproduce the exact issue on my end, can you please test it out once just to confirm if the issue is resolved?