Log completely unusable when an entry has corrupt serialized data.

[klonos]

This is to crossport https://www.drupal.org/project/drupal/issues/2790857, which was recently committed to D7 core:

If an entry in the dblog has corrupt serialized data, the dblog page (/admin/reports/dblog) will throw an exception and will not load.

If unserialize fails, then a boolean is sent to t() leading to a fatal exception.
$output = t($event->message, unserialize($event->variables));

[indigoxela]

Fancy, I never ran into this before, but I can confirm that Backdrop is also affected.

I created a dump for a watchdog table and edited one of the records to make the "variables" column content unusable (added some random characters). After importing and going to /admin/reports/dblog I get:

Then applied the patch and went back to /admin/reports/dblog - and the page works again. The broken entry doesn't show up anymore.

[bugfolder]

Code reviewed, LGTM.

[quicksketch]

Thanks for reviewing this @bugfolder! Looks like a good port from Drupal 7. I merged backdrop/backdrop#4190 into 1.x and 1.26.x. Thanks @klonos and @indigoxela for the PR and testing!