whatsNew.adoc

This section covers all the new features introduced in Grails 8

Overview

Grails 8 is a major release that includes new features, improvements, and dependency upgrades. This release focuses on enhancing the developer experience, improving performance, and ensuring compatibility with the latest technologies.

For detailed information on how to upgrade to Grails 8, including major dependency changes, please see the Upgrading from Grails 7 to Grails 8 section. Notable new features are included below.

GSP Tag Library Improvements

Grails 8 continues the move toward method-based TagLib handlers while preserving compatibility with existing closure-based tags. Method-defined tags now bind named attributes more predictably, exclude inherited framework and Object methods from tag dispatch, and preserve real namespace property getters.

The Grails Gradle extension now defaults preserveParameterNames to true, so application Groovy compilation preserves method parameter names for features such as typed method TagLib arguments.

Tag library unit tests also clean up and rebuild TagLib metadata automatically between features. Tests that use TagLibUnitTest no longer need to manage purgeTagLibMetaClass, and specs that mock additional tag libraries continue to work across feature methods.

@GrailsCompileStatic on Controllers That Use Tag Libraries

Controllers annotated with @GrailsCompileStatic can now invoke tag library methods without compile-time errors.

Both calling patterns are supported out of the box:

import grails.compiler.GrailsCompileStatic

@GrailsCompileStatic
class BookController {

    def index() {
        // Direct call in the default namespace
        response.writer << link(controller: 'book', action: 'list')

        // Namespaced call via a dispatcher property
        response.writer << my.customTag(attr: 'value')
    }
}

The new ControllerTagLibTypeCheckingExtension (bundled with @GrailsCompileStatic) recognises controller classes by convention and marks tag dispatch points as permissible dynamic calls, while leaving the rest of the controller fully type-checked.