Compile error after Migrating

[theExo]

Hey folks,

im pretty new to Processwire. A client of mine asked me to migrate his old (v2.5) Processwire Website. On his server its running on PHP 5.3 and i want to upgrade + migrate the site at the same time. I Downloaded the Site from his server to set it up locally, replaced the /wire directory, index.php and .htaccess with the files of the latest version. After that i changed the DB Connection details in the config.php, swapped to PHP 7.4 and now, when i open up the site on my localhost i get this error:

compile(\ProcessWire\wire("config")->paths->root . "site/templates/includes/head.inc.php",array('includes'=>true,'namespace'=>true,'modules'=>true,'skipIfNamespace'=>true)))?> 
compile(\ProcessWire\wire("config")->paths->root . "site/templates/includes/header.inc.php",array('includes'=>true,'namespace'=>true,'modules'=>true,'skipIfNamespace'=>true)))?> 
compile(\ProcessWire\wire("config")->paths->root . "site/templates/includes/start_content.inc.php",array('includes'=>true,'namespace'=>true,'modules'=>true,'skipIfNamespace'=>true)))?> 
compile(\ProcessWire\wire("config")->paths->root . "site/templates/includes/footer.inc.php",array('includes'=>true,'namespace'=>true,'modules'=>true,'skipIfNamespace'=>true)))?> 

The page itself doesnt load, just a white space with this stuff on it

I checked if the files exist, they do.

I hope anyone can help me with that ? Thanks in advance!

Edited July 2, 2021 by theExo
tags missing

[Macrura]

Here are some quick items to consider, based on how I would upgrade a site:

- start over, back to the original version (2.5)
- Login as superadmin
- enable debug mode from the config
- Make sure the site is fully functional on localhost in the original version;
    if there are PHP errors/warnings on the front end, e.g. related to php version, fix those first before upgrading the site
- Upgrade any modules that are compatible with 2.5
- once the site is running with no errors on 2.5, upgrade the core to latest stable version  
    if you replace the htaccess, make note of any settings that need to be copied over (www, https, pro cache etc)
- upgrade all modules to the latest using the upgrades module

Note that the new core compiles the non-namespaced files. You can clear the filecompiler cache (bottom of modules) if you see any errors related to that,

if you still see no content on the homepage, check for js/browser errors;
Check how assets are being referenced; paths could not be resolving.

[theExo]

Thats stuff i already kept in mind. however im trying to setup the site on a localhost and that doesnt work

[Macrura]

There are just a lot of possible reasons, so hard to say what's happening; You need to check logs, see what the actual errors are, which files errors are in.. explain your complete plan/process as to how you are going to upgrade this. 

You don't even really need to download and upgrade it; I've done dozens of upgrades on live sites. I'd be more concerned about the PHP version upgrade than the PW upgrade; I've had close to zero issues with PW core upgrades; Issues if any usually come from modules or front end code. Before i upgrade any PHP version that a site is running on, i first upgrade everything to ensure compatibility and then do incremental upgrades if the server offers multiple PHP versions - 7.2, then 7.3; 7.4 seems to have the most breaking changes and i'm currently upgrading many sites and finding 7.4 to be the hardest upgrade.