Inheriting Variables from Parent Theme

Oct 13, 2025 by talynt.org 14 views

Discussion Category: Hooks, 10, 11

Additional Information: You have created a module that creates a content type with fields. Now, you are trying to create a custom Twig template for that content type. However, you are facing an issue where the custom Twig template is not inheriting variables from the parent theme.

Understanding the Issue

When creating a custom Twig template in a module, it's essential to understand how Twig inheritance works in Drupal. Twig templates can inherit variables from parent themes using the @parent keyword. However, if the custom Twig template is not inheriting variables, it's likely due to a misunderstanding of how Twig inheritance works or a configuration issue.

Function mymodule_theme($existing, $type, $theme, $...

In your module, you have defined a function mymodule_theme that is responsible for registering the custom Twig template. However, the function is not correctly configured to inherit variables from the parent theme.

function mymodule_theme($existing, $type, $theme, $path) {
  $build = array();
  $build['variables'] = array();
  $build['variables']['#attached']['library'][] = 'mymodule/mymodule';
  $build['variables']['#attached']['css'][] = 'path/to/mymodule.css';
  return $build;
}

Inheriting Variables from Parent Theme

To inherit variables from the parent theme, you need to use the @parent keyword in your custom Twig template. However, in your module, you need to configure the mymodule_theme function to pass the variables to the custom Twig template.

function mymodule_theme($existing, $type, $theme, $path) {
  $build = array();
  $build['variables'] = array();
  $build['variables']['#attached']['library'][] = 'mymodule/mymodule';
  $build['variables']['#attached']['css'][] = 'path/to/mymodule.css';
  $build['variables']['#parent'] = 'parent_theme';
  return $build;
}

Custom Twig Template

In your custom Twig template, you can use the @parent keyword to inherit variables from the parent theme.

{% extends 'parent_theme.html.twig' %}
{% block content %}
{{ parent() }}
{{ variables['#attached']['library'] }}
{{ variables['#attached']['css'] }}
{% endblock %}

Conclusion

In conclusion, the custom Twig template in your module is not inheriting variables from the parent theme because the mymodule_theme function is not correctly configured to pass the variables to the custom Twig template. By using the @parent keyword in your custom Twig template and configuring the mymodule_theme function to pass the variables, you can inherit variables from the parent theme.

Troubleshooting Tips

Make sure that the mymodule_theme function is correctly registered in the hook_theme function.
Verify that the custom Twig template is correctly extending the parent theme using the @parent keyword.
Check that the variables are being passed to the custom Twig template using the #attached key.

Additional Resources

Twig Documentation
Drupal Theming Documentation
Custom Twig in Module Not Inheriting Variables? Q&A =====================================================

Discussion Category: Hooks, 10, 11

Q: What is Twig Inheritance in Drupal?

A: Twig inheritance in Drupal allows you to create custom Twig templates that inherit variables from parent themes. This is achieved using the @parent keyword in your custom Twig template.

Q: How do I configure the `mymodule_theme` function to inherit variables from the parent theme?

A: To configure the mymodule_theme function to inherit variables from the parent theme, you need to use the #parent key in the $build array. This will pass the variables to the custom Twig template.

function mymodule_theme($existing, $type, $theme, $path) {
  $build = array();
  $build['variables'] = array();
  $build['variables']['#attached']['library'][] = 'mymodule/mymodule';
  $build['variables']['#attached']['css'][] = 'path/to/mymodule.css';
  $build['variables']['#parent'] = 'parent_theme';
  return $build;
}

Q: How do I use the `@parent` keyword in my custom Twig template to inherit variables from the parent theme?

A: To use the @parent keyword in your custom Twig template, you need to extend the parent theme using the @parent keyword.

{% extends 'parent_theme.html.twig' %}
{% block content %}
{{ parent() }}
{{ variables['#attached']['library'] }}
{{ variables['#attached']['css'] }}
{% endblock %}

Q: What are some common issues that can cause the custom Twig template to not inherit variables from the parent theme?

A: Some common issues that can cause the custom Twig template to not inherit variables from the parent theme include:

The mymodule_theme function is not correctly registered in the hook_theme function.
The custom Twig template is not correctly extending the parent theme using the @parent keyword.
The variables are not being passed to the custom Twig template using the #attached key.

Q: How do I troubleshoot issues with the custom Twig template not inheriting variables from the parent theme?

A: To troubleshoot issues with the custom Twig template not inheriting variables from the parent theme, you can try the following:

Verify that the mymodule_theme function is correctly registered in the hook_theme function.
Check that the custom Twig template is correctly extending the parent theme using the @parent keyword.
Verify that the variables are being passed to the custom Twig template using the #attached key.

Q: What are some additional resources that can help me learn more about Twig inheritance in Drupal?

A: Some additional resources that can help you learn more about Twig inheritance in Drupal include: