renderPlain on a node render array causes RuntimeException if the node renders a view programmatically [#3350137]

Problem

When using renderPlain() to send the HTML of a page over a 3rd party API, there is a Runtime Exception if the page renders any view programmatically (e.g. through a node preprocess). The renderPlain() was called from a shutdown function

Failed to start the session because headers have already been sent by "/app/vendor/symfony/http-foundation/Response.php" at line 384.

The site is currently on 9.5.5. I have tested with 9.5.6-dev and it has not been fixed. I have done some debugging and found that the bug was introduced in 9.5.4.

Steps to reproduce

Use Drupal core 9.5.4+
Create a node that has a programmatically generated view (i.e. $view = Views::getView()... $view->preview())
In a shut down function, call renderPlain() on a render array containing the above node

Proposed resolution

I have not got a solution. If I can find a fix I will create a patch and add it here.
If anyone thinks this is working as expected, then please make suggestions on how I can correct this.

Comment	File	Size	Author
#18	core-render-plain-runtime-exception-3350137-18.patch	498 bytes	dejan0
#9	core-render-plain-runtime-exception-3350137-9.patch	829 bytes	scambler
#7	core-render-plain-runtime-exception-3350137-7.patch	712 bytes	scambler
#3	core-render-plain-runtime-exception-3350137-3.patch	788 bytes	scambler
#2	core-render-plain-runtime-exception-3350137-2.patch	692 bytes	scambler

Issue fork drupal-3350137

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3350137-renderplain-on-a changes, plain diff MR !12568
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Comments

Comment #1

24 March 2023 at 09:49

scambler created an issue. See original summary.

Comment #2

scambler commented 24 March 2023 at 11:24

Status	File	Size
new	core-render-plain-runtime-exception-3350137-2.patch	692 bytes

I have found the line which is causing the error and have reverted it to what it was on 9.5.3.

Comment #3

scambler commented 24 March 2023 at 11:27

Status	File	Size
new	core-render-plain-runtime-exception-3350137-3.patch	788 bytes

This next patch is more of a suggestion and not one I will be using on a production site (unless others approve it) as I am not confident of the consequences elsewhere on the site.

Comment #4

cilefen commented 24 March 2023 at 11:28

Thank you for reporting a bug.

Can we get some sample reproduction code as a way to clarify the steps to reproduce please?

Can you execute a git bisect, or a commit analysis to identify the core commit that changed the behavior please?

Comment #5

cilefen commented 24 March 2023 at 11:29

^ I fixed a funny auto type in my comment.

Comment #6

scambler commented 24 March 2023 at 11:30

Component:

render system

» views.module

Comment #7

scambler commented 24 March 2023 at 11:49

Status	File	Size
new	core-render-plain-runtime-exception-3350137-7.patch	712 bytes

*Correcting file path for patch 2

Comment #8

larowlan

🇦🇺🏝.au GMT+10

commented 25 March 2023 at 20:33

Status:

Active

» Postponed (maintainer needs more info)

For #4

Comment #9

scambler commented 27 March 2023 at 09:52

Status	File	Size
new	core-render-plain-runtime-exception-3350137-9.patch	829 bytes

2 files were hidden/shown/deleted

Status	File	Size
hidden	core-render-plain-runtime-exception-3350137-2.patch	692 bytes
hidden	core-render-plain-runtime-exception-3350137-3.patch	788 bytes

@cilefen I will create some sample code to help reproduce when I next get some free time

Comment #10

lendude

Dutch

Amsterdam

commented 27 March 2023 at 14:40

Looking at the proposed change in #9 the culprit would have been #3260652: Feature "Remember the last selection" for views exposed filters doesn't work anymore, and can't recall anything else messing with sessions, so that sounds likely. That did add a check:

      if (empty($this->exposed_input) && $this->request->hasSession()) {
        $session = \Drupal::request()->getSession();

But maybe that is not sufficient is some cases?

Create a node that has a programmatically generated view (i.e. $view = Views::getView()... $view->preview())
In a shut down function, call renderPlain() on a render array containing the above node

Sounds pretty edge-case to me, so if that is indeed the only way to run into this, I'm not surprised we missed it.

Comment #11

scambler commented 29 March 2023 at 08:55

The code basically goes like this:

function my_module_node_update($node) {
  // Do some checks...
  // Do some stuff...
  
  drupal_register_shutdown_function('my_module_send_request', $node);
}

function my_module_send_request($node) {
  // Manually build up the page into a render array.
  $builder = Drupal::entityTypeManager()->getViewBuilder('node');
  $node_render_array = $builder->view($node, 'full');
  $build = [
    '#type' => 'html',
      'page' => [
        '#type' => 'page',
        '#title' => $node->label(),
        '#head_title' => [$node->label()],
        'content' => $node_render_array,
     ]
  ];
  
  Drupal::service('renderer')->renderPlain($build);

  return $build;
}

function my_module_preprocess_node(&$variables) {
  $view_id = 'watchdog';
  $display = 'page';
  if ($view = Views::getView($view_id)) {
    $view->setDisplay($display);
    $view->executeDisplay($display);
    $preview = $view->preview();
    $variables['content']['glossary'] = $preview;
    $variables['display'] = $display;
  }
}

The problem occurs in the renderPlain() when inside the preprocess node and executing/previewing the view. I have tried to tweak this so that it can work on a vanilla site, but I haven't tested it myself yet.

Also worth noting that we have another process that is calls my_module_send_request manually and it works fine. Which further points at the shutdown function being the 'problem'.

Comment #12

scambler commented 24 April 2023 at 16:11

Status:

Postponed (maintainer needs more info)

» Needs review

Comment #13

24 April 2023 at 16:53

The last submitted patch, 7: core-render-plain-runtime-exception-3350137-7.patch, failed testing. View results

Comment #14

smustgrave commented 24 April 2023 at 23:06

Status:	Needs review	» Needs work
Issue tags:		+Needs Review Queue Initiative, +Needs tests

Believe next steps would be to write a test case or extend an existing test to show this issue.

Comment #15

24 April 2023 at 23:06

Version:

9.5.x-dev

» 11.x-dev

Drupal core is moving towards using a “main” branch. As an interim step, a new 11.x branch has been opened, as Drupal.org infrastructure cannot currently fully support a branch named main. New developments and disruptive changes should now be targeted for the 11.x branch. For more information, see the Drupal core minor version schedule and the Allowed changes during the Drupal core release cycle.

Comment #16

devad commented 30 July 2024 at 22:10

Just to confirm that patch #9 fixed a node render RuntimeExceptions reported by search_api module in my case.

RTBC for me.

My config: D10.3.1. The patch #9 applies successfully.

Previous error message was:

Type	search_api

Date	Tuesday, July 30, 2024 - 23:55

User	Anonymous (not verified)

Location	https://my.com/node/2706/edit

Referrer	https://my.com/node/2706/edit

Message	RuntimeException while trying to render item entity:node/2706:en with view mode search_index for search index Default content index: Failed to start the session because headers have already been sent by "/home/my/public_html/vendor/symfony/http-foundation/Response.php" at line 1315. in Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->start() (line 132 of /home/my/public_html/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php).

Severity	Error

Operations	

Backtrace	
#0 /home/my/public_html/core/lib/Drupal/Core/Session/SessionManager.php(162): Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->start()
#1 /home/my/public_html/core/lib/Drupal/Core/Session/SessionManager.php(127): Drupal\Core\Session\SessionManager->startNow()
#2 /home/my/public_html/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php(311): Drupal\Core\Session\SessionManager->start()
#3 /home/my/public_html/vendor/symfony/http-foundation/Session/Session.php(222): Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->getBag()
#4 /home/my/public_html/vendor/symfony/http-foundation/Session/Session.php(242): Symfony\Component\HttpFoundation\Session\Session->getBag()
#5 /home/my/public_html/vendor/symfony/http-foundation/Session/Session.php(69): Symfony\Component\HttpFoundation\Session\Session->getAttributeBag()
#6 /home/my/public_html/core/modules/views/src/ViewExecutable.php(762): Symfony\Component\HttpFoundation\Session\Session->get()
#7 /home/my/public_html/core/modules/views/src/Plugin/views/display/DisplayPluginBase.php(2242): Drupal\views\ViewExecutable->getExposedInput()
#8 [internal function]: Drupal\views\Plugin\views\display\DisplayPluginBase->elementPreRender()
#9 /home/my/public_html/core/lib/Drupal/Core/Security/DoTrustedCallbackTrait.php(113): call_user_func_array()
#10 /home/myi/public_html/core/lib/Drupal/Core/Render/Renderer.php(870): Drupal\Core\Render\Renderer->doTrustedCallback()
#11 /home/my/public_html/core/lib/Drupal/Core/Render/Renderer.php(432): Drupal\Core\Render\Renderer->doCallback()
#12 /home/my/public_html/core/lib/Drupal/Core/Render/Renderer.php(504): Drupal\Core\Render\Renderer->doRender()
#13 /home/my/public_html/core/lib/Drupal/Core/Render/Renderer.php(504): Drupal\Core\Render\Renderer->doRender()
#14 /home/my/public_html/core/lib/Drupal/Core/Render/Renderer.php(248): Drupal\Core\Render\Renderer->doRender()
#15 /home/my/public_html/core/lib/Drupal/Core/Template/TwigExtension.php(475): Drupal\Core\Render\Renderer->render()
#16 /home/my/public_html/sites/default/files/php/twig/66a95f91ba545_node.html.twig_NDqtWxoLpyRFa6oXHJ6UnJr_a/C7a4KCDRNPTvx_Z-GXBGdoFPJloemDJndA3-1dBnQp4.php(114): Drupal\Core\Template\TwigExtension->escapeFilter()
#17 /home/krkswami/public_html/vendor/twig/twig/src/Template.php(360): __TwigTemplate_7a9ce1f8bd9ce10a30ff475b2491dced->doDisplay()
#18 /home/my/public_html/vendor/twig/twig/src/Template.php(335): Twig\Template->yield()
#19 /home/my/public_html/vendor/twig/twig/src/TemplateWrapper.php(38): Twig\Template->render()
#20 /home/my/public_html/core/themes/engines/twig/twig.engine(33): Twig\TemplateWrapper->render()
#21 /home/my/public_html/core/lib/Drupal/Core/Theme/ThemeManager.php(348): twig_render_template()
#22 /home/my/public_html/core/lib/Drupal/Core/Render/Renderer.php(491): Drupal\Core\Theme\ThemeManager->render()
#23 /home/my/public_html/core/lib/Drupal/Core/Render/Renderer.php(248): Drupal\Core\Render\Renderer->doRender()
#24 /home/my/public_html/core/lib/Drupal/Core/Render/Renderer.php(165): Drupal\Core\Render\Renderer->render()
#25 /home/my/public_html/core/lib/Drupal/Core/Render/Renderer.php(638): Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}()
#26 /home/myi/public_html/core/lib/Drupal/Core/Render/Renderer.php(166): Drupal\Core\Render\Renderer->executeInRenderContext()
#27 /home/my/public_html/modules/contrib/search_api/src/Plugin/search_api/processor/RenderedItem.php(222): Drupal\Core\Render\Renderer->renderInIsolation()
#28 /home/my/public_html/core/lib/Drupal/Component/Utility/DeprecationHelper.php(40): Drupal\search_api\Plugin\search_api\processor\RenderedItem->Drupal\search_api\Plugin\search_api\processor\{closure}()
#29 /home/my/public_html/modules/contrib/search_api/src/Plugin/search_api/processor/RenderedItem.php(223): Drupal\Component\Utility\DeprecationHelper::backwardsCompatibleCall()
#30 /home/my/public_html/modules/contrib/search_api/src/Item/Item.php(281): Drupal\search_api\Plugin\search_api\processor\RenderedItem->addFieldValues()
#31 /home/my/public_html/modules/contrib/search_api/src/Entity/Index.php(987): Drupal\search_api\Item\Item->getFields()
#32 /home/my/public_html/modules/contrib/search_api/src/Utility/PostRequestIndexing.php(92): Drupal\search_api\Entity\Index->indexSpecificItems()
#33 /home/my/public_html/core/lib/Drupal/Core/DrupalKernel.php(723): Drupal\search_api\Utility\PostRequestIndexing->destruct()
#34 /home/my/public_html/index.php(22): Drupal\Core\DrupalKernel->terminate()
#35 {main}

Comment #17

bkosborne

English

New Jersey, USA

commented 4 October 2024 at 14:38

I've run into a similar problem, but my node doesn't contain a view, but instead contains a form. FormBuilder::buildForm has this chunk of code

    if ($request->getSession()->has('batch_form_state')) {
      // We've been redirected here after a batch processing. The form has
      // already been processed, but needs to be rebuilt. See _batch_finished().
      $session = $request->getSession();
      $form_state = $session->get('batch_form_state');
      $session->remove('batch_form_state');
      return $this->rebuildForm($form_id, $form_state);
    }

So when it tries to build a form, it checks if the session has batch_form_state data set. If the session isn't yet started, it tries to start it, but NativeSessionStorage refuses to do so because the HTTP response headers have already been set (by the page's initial response).

That code should probably check that the session is actually started before checking if it has data, but I'm not really sure.

Comment #18

dejan0 commented 4 March 2025 at 17:06

Status	File	Size
new	core-render-plain-runtime-exception-3350137-18.patch	498 bytes

Yes, I’m experiencing the same issue with FormBuilder::buildForm. The $request->getSession()->has('batch_form_state') check always fails when headers have already been sent.

Symfony’s NativeSessionStorage (symfony/http-foundation) explicitly throws an exception in this case: https://github.com/symfony/http-foundation/blob/7.3/Session/Storage/Nati...

It might make sense to add this check in SessionManager::startNow() to handle this case better...

Comment #19

ankondrat4 commented 1 July 2025 at 13:53

Patch #18 https://www.drupal.org/project/drupal/issues/3350137#comment-16014932 works for me on Drupal 10.5.0
I have created issue fork with these changes.
Please review.

Comment #20

1 July 2025 at 13:56

ankondrat4 opened merge request !12568

Comment #21

ankondrat4 commented 1 July 2025 at 13:57

Status:

Needs work

» Needs review

Comment #22

smustgrave commented 2 July 2025 at 01:40

Status:

Needs review

» Needs work

Thanks! See it was previously tagged for tests so moving to NW for that.

Comment #23

2 July 2025 at 01:40

Version:

11.x-dev

» main

Drupal core is now using the main branch as the primary development branch. New developments and disruptive changes should now be targeted to the main branch.

Comment #24

tvalimaa commented 1 September 2026 at 09:49

The fix (!headers_sent() && parent::start()) is already present in SessionManager.php at line 138 — it's been merged into Drupal core 11.4.5.

renderPlain on a node render array causes RuntimeException if the node renders a view programmatically

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Proposed resolution

Issue fork drupal-3350137

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