Magento 2.4.9 with use_application_lock enabled and file based locking, experiences hanging indexers

[hostep]

Preconditions and environment

• Magento version: 2.4.9, also tested on latest 2.4-develop (8f16a0d)

Steps to reproduce

1. Setup new Magento shop from scratch
2. Confirm that bin/magento indexer:reindex works without issues
3. Open the app/etc/env.php file and add this extra config:

    'indexer' => [
        'use_application_lock' => true
    ],
    'lock' => [
        'provider' => 'file',
        'config' => [
            'path' => 'var/locks'
        ]
    ],

4. Run bin/magento indexer:reindex notice that it starts but never finishes

Expected result

Expect indexers to finish without issues when both file based locking is configured and use_application_lock is enabled

Actual result

Hanging indexers, never finishing, being stuck in a never-ending while loop

Additional information

Issue seems to have been introduced by these 4 lines in Magento 2.4.9, which was supposed to fix: #40102
See commit that introduced the problem (AC-15270)

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]

Hi @hostep. Thank you for your report.
To speed up processing of this issue, make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce.

• For more details, review the Magento Contributor Assistant documentation.
• Add a comment to assign the issue: @magento I am working on this
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[github-jira-sync-bot]

✅ Jira issue https://jira.corp.adobe.com/browse/AC-17457 is successfully created for this GitHub issue.

[engcom-Bravo]

Hi @hostep,

Thanks for your reporting and collaboration.

We have tried to reproduce the issue in latest 2.4-develop instance and we are able to reproduce the issue and Hanging indexers, never finishing, being stuck in a never-ending while loop.Hence Confirming the issue.

Thanks.