500 Error upon changing theme (error log included)

[fixxer1]

Hello respected experts.

Prestashop 8.0.4

After I've changed my current custom theme to classic, entire backoffice along with the front crashed. Please help to solve this, I only need to get back to my custom theme.

Here is what the log says:

 

[19-Jul-2023 10:25:38 UTC] PHP Fatal error:  Uncaught Symfony\Component\Yaml\Exception\ParseException: Unable to parse at line 63 (near "  modules_to_hook:"). in /home/zegyntblo26o/public_html/cstms_store/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php:493
Stack trace:
#0 /home/zegyntblo26o/public_html/cstms_store/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php(533): Symfony\Component\Yaml\Parser->doParse()
#1 /home/zegyntblo26o/public_html/cstms_store/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php(329): Symfony\Component\Yaml\Parser->parseBlock()
#2 /home/zegyntblo26o/public_html/cstms_store/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php(96): Symfony\Component\Yaml\Parser->doParse()
#3 /home/zegyntblo26o/public_html/cstms_store/src/Core/Addon/Theme/ThemeRepository.php(167): Symfony\Component\Yaml\Parser->parse()
#4 /home/zegyntblo26o/public_html/cstms_store/src/Core/Addon/Theme/ThemeRepository.php(85): PrestaShop\PrestaShop\Core\Addon\Theme\ThemeRepository->getConfigFromFile()
#5 /home/zegyntblo26o/public_html/cstms_store/classes/shop/Shop.php(504): PrestaShop\PrestaShop\Core\Addon\Theme\ThemeRepository->getInstanceByName()
#6 /home/zegyntblo26o/public_html/cstms_store/classes/shop/Shop.php(147): ShopCore->setTheme()
#7 /home/zegyntblo26o/public_html/cstms_store/classes/shop/Shop.php(425): ShopCore->__construct()
#8 /home/zegyntblo26o/public_html/cstms_store/config/config.inc.php(117): ShopCore::initialize()
#9 /home/zegyntblo26o/public_html/cstms_store/index.php(27): require('/home/zegyntblo...')
#10 {main}
  thrown in /home/zegyntblo26o/public_html/cstms_store/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php on line 493

Edited July 19, 2023 by fixxer1 (see edit history)

[fixxer1]

So after little investigations I came to this:

The information in logs refers to problem with theme.yml file. As I go to search for it, I noticed that classic theme folder appeared to be renamed in the '/themes' folder (I don't remember why I did this). I changed the name of the folder back to "classic", so now everything is supposed to be fine, the .yml file is on it's place, it says name: classic; display_name: Classic in the beginning.

But I'm still getting a 500-crash of both back and front offices. 

What should I check now?

Edited July 19, 2023 by fixxer1 (see edit history)

[fixxer1]

After this I thought there has to be the way to change the theme back to the one that I created through FTP, bypassing back-office. I went to /classes/shop/Shop.php and in the line 502 I changed 

$this->theme_name = 'classic';

to

$this->theme_name = 'cstms';

So now I should have my website back on my custom theme and working again. But still I have a crash. Please let me know how to reconstruct the site? 

[fixxer1]

Finally have restored access to the site by checking this:

In /home/zegyntblo26o/public_html/cstms_store/config/themes/cstms directory there was shop1.json file missing. 

Found this file in /home/zegyntblo26o/public_html/cstms_store/config/themes/cstms_theme dir. Why on earth did it go there - I don't know...

 

So, can close the topic, may be this helps somebody in the future.