$request->getFullActionName() returns "__" on Homepage

[MagePsycho]

Preconditions and environment

• Magento 2.4.4
• FPC enabled
• Observe the event controller_front_send_response_before

Steps to reproduce

1. Observe the event controller_front_send_response_before on frontend area (etc/frontend/events.xml)
2. Get the get full action name from the observer class as $fullActionName = $observer->getEvent()->getRequest()->getFullActionName()

public function execute(Observer $observer)
{
    $request = $observer->getEvent()->getRequest();
    $fullActionName = $request->getFullActionName();
    file_put_contents(BP . '/var/log/http.log', $fullActionName . PHP_EOL, FILE_APPEND | LOCK_EX);
    // $fullActionName gives __ value 
    // ...    
}

3. Reload the homepage for one more time (to make sure the page is cached now). If FPC is disabled, make sure to enable it.
4. Now load the homepage and check the value of $fullActionName. It will always return __ (Please refer to the attached screenshot)
   

Expected result

$fullActionName should give cms_index_index

Actual result

$fullActionName is giving __

Additional information

No response

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

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[m2-assistant]

Hi @engcom-Echo. Thank you for working on this issue.
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[engcom-Echo]

Hello @MagePsycho,

This issue is reproducible on Magento 2.4-develop branch.
Please find the below screen for your reference.

Hence we are confirming this issue.

Steps followed as given in above comment.

Thanks

[github-jira-sync-bot]

✅ Jira issue https://jira.corp.magento.com/browse/AC-5961 is successfully created for this GitHub issue.

[m2-assistant]

✅ Confirmed by @engcom-Echo. Thank you for verifying the issue.
Issue Available: @engcom-Echo, You will be automatically unassigned. Contributors/Maintainers can claim this issue to continue. To reclaim and continue work, reassign the ticket to yourself.

[artskirk]

@magento I am working on this

[stkrelax]

also reproduced on 2.4.2-p1

HINT

ONE pagecall ->

Magento\UrlRewrite\Controller\Router\Interceptor returns Magento\Framework\App\Action\Forward\Interceptor
which executes , which causes controller_action_predispatch, which causes getFullactionName be '__'
next is

Magento\Framework\App\Router\Base\Interceptor returns Magento\Catalog\Controller\Product\View\Interceptor
which executes, which causes controller_action_predispatch a second time with getFullactionName be 'catalog_product_view'

[MagePsycho]

@stkrelax
Note that controller_action_predispatch is not executed for the next time when the page is served via FPC.

[stkrelax]

still present in 2.4.5-p1