twig dump() creates WSOD error

Question

this is my first Drupal installation (I'm a symfony dev) and I've spent several hours trying to get dump() working. However it just causes a WSOD.

Maybe related: I'm unable to install kint, there's issues with it now being a sub-module of devel and I haven't been able to install it.

Settings:

• Drupal version 8.9.1
• memory limit set to 6,000mb
• execution time set to 90 seconds
• Windows
• acquia dev desktop
• php 7.3.15
• Apache/2.4.33 (Win64) OpenSSL/1.1.0h mod_fcgid/2.3.9

If anyone has suggestions I'm keen to hear it! Drupal is quite interesting from what I've seen so far. It's been a bit frustrating as someone new to Drupal, trying to get basic things working.

== Update ==

I have corrected a config error I made while configuring the site. See here (for correct config).

Calls to dump() (in twig) for null variables work, but {{ dump(items) }} will hang and then result in a 500 error (see link above).

Answer 1

I've solved this.

In Drupal, modules also use composer (which I wasn't aware of). The vardumper module depends on the symfony/var-dumper package.

Running:

composer require --dev symfony/var-dumper

causes dependency conflicts, however using:

composer update

Will install the var-dumper package, fix the problem - now I can see very beautiful variable dumps.

Lesson learnt:

• Always check composer for dependency errors.