XF 2.2 Manual upgrading from 2.2.13 to 2.2.15 - compileAst() error

[yar]

When doing manual upgrade process from v2.2.13 to 2.2.15 I am getting error like:

TypeError: XF\Template\Compiler::compileAst(): Argument #1 ($ast) must be of type XF\Template\Compiler\Ast, bool given, called in /opt/APP/public/community/src/XF/Service/Template/Compile.php on line 28 in src/XF/Template/Compiler.php at line 241

1. XF\Template\Compiler->compileAst() in src/XF/Service/Template/Compile.php at line 28
2. XF\Service\Template\Compile->recompile() in src/XF/Service/Phrase/Compile.php at line 71
3. XF\Service\Phrase\Compile->recompileIncludeContent() in src/XF/Entity/Phrase.php at line 200
4. XF\Entity\Phrase->_postDelete() in src/XF/Mvc/Entity/Entity.php at line 1664
5. XF\Mvc\Entity\Entity->delete() in src/XF/AddOn/DataType/AbstractDataType.php at line 124
6. XF\AddOn\DataType\AbstractDataType->deleteEntity() in src/XF/AddOn/DataType/AbstractDataType.php at line 99
7. XF\AddOn\DataType\AbstractDataType->deleteOrphanedSimple() in src/XF/AddOn/DataType/Phrase.php at line 116
8. XF\AddOn\DataType\Phrase->deleteOrphanedAddOnData() in src/XF/Job/AddOnData.php at line 114
9. XF\Job\AddOnData->run() in src/XF/Job/Atomic.php at line 40
10. XF\Job\Atomic->run() in src/XF/Job/Manager.php at line 260
11. XF\Job\Manager->runJobInternal() in src/XF/Job/Manager.php at line 202
12. XF\Job\Manager->runJobEntry() in src/XF/Job/Manager.php at line 153
13. XF\Job\Manager->runUnique() in src/XF/Install/Controller/AbstractController.php at line 24
14. XF\Install\Controller\AbstractController->manualJobRunner() in src/XF/Install/Controller/Upgrade.php at line 266
15. XF\Install\Controller\Upgrade->actionRunJob() in src/XF/Mvc/Dispatcher.php at line 352
16. XF\Mvc\Dispatcher->dispatchClass() in src/XF/Mvc/Dispatcher.php at line 259
17. XF\Mvc\Dispatcher->dispatchFromMatch() in src/XF/Mvc/Dispatcher.php at line 115
18. XF\Mvc\Dispatcher->dispatchLoop() in src/XF/Mvc/Dispatcher.php at line 57
19. XF\Mvc\Dispatcher->run() in src/XF/App.php at line 2487
20. XF\App->run() in src/XF.php at line 524
21. XF::runApp() in install/index.php at line 14

Any hints where to look for the problem and what could be wrong? What is "Ast"?

UPDATE: I have reverted my PAGE_CONTAINER template and in that case upgrade process passed through smoothly. I had pretty extensive changes there so it looks like something has interfered with upgrade process and eventually made it broken. (I would expect some "template merge" conflicts, etc)

 

[yar]

I have solved my problem. If anyone else would be facing it, I have highlighted my custom PAGE_CONTAINER diff that was breaking upgrade process with error above (some old forgotten styles comments)-