URL mapping group defaults support

[codeconsole]

Dramatically simplifies group url mappings by allowing parameter inheritance.

e.g.

group "/api", namespace: 'api', controller: 'defaultCtrl', {
    "/special"(controller: 'specialCtrl', action: 'handle')  // overrides controller
    "/normal"(action: 'index')                                // inherits controller
}

you can even do

group "/members", namespace: 'api', controller: 'member', {
    "/$action?"()  // supports / and action resolution
    "/$username"(action: 'profile') 
}

[Copilot]

Pull request overview

Adds support for group-level default mapping parameters in the URL mappings DSL, so child mappings can inherit controller/namespace/etc. from a surrounding group(...) and override them selectively.

Changes:

• Introduces a new group overload intended to accept default mapping parameters and apply them to child mappings.
• Extends MetaMappingInfo with a groupDefaults map to support inheritance across nested groups/mappings.
• Adds documentation and a new Spock spec covering inheritance/override behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
grails-web-url-mappings/src/test/groovy/org/grails/web/mapping/GroupDefaultsSpec.groovy	Adds tests for group defaults inheritance/override and nested group inheritance.
grails-web-url-mappings/src/main/groovy/org/grails/web/mapping/MetaMappingInfo.groovy	Stores groupDefaults on mapping metadata to enable inheritance.
grails-web-url-mappings/src/main/groovy/org/grails/web/mapping/DefaultUrlMappingEvaluator.java	Implements group-defaults support and inheritance during mapping evaluation.
grails-doc/src/en/guide/theWebLayer/urlmappings/mappingToControllersAndActions.adoc	Documents the new “Group Defaults” feature with examples and supported keys.

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[Copilot]

This override has the same argument-order issue as the parent overload. For nested groups, Groovy will call group(String, Map, Closure) when using group "/x", controller:'c', { ... }, but this method only matches group(Map, String, Closure), causing nested group defaults to fail at runtime.

Suggested change

	}
	}
	@Override
	public void group(String uri, Map<String, Object> defaults, Closure<?> mappings) {
	if (parentResource != null) {
	uri = parentResource.uri.concat(uri);
	}
	super.group(uri, defaults, mappings);
	}

[sbglasius]

@copilot Having a Map<String, Object> default first as arguments makes it a Named argument collector.

[Copilot]

applyGroupDefaults currently only updates MetaMappingInfo. When URL mappings are evaluated from a Script (binding != null), controller/action/namespace defaults are resolved from the script Binding (see getVariableFromNamedArgsOrBinding), not from MetaMappingInfo, so these defaults may be ignored in the common URLMappings.groovy path. To make group defaults effective for Script-based mappings, either (1) push defaults into the Binding for the duration of the group closure (and restore afterward), or (2) update the variable resolution logic to fall back to the defaultValue when the Binding doesn't define the key.

[Copilot]

These tests exercise DefaultUrlMappingEvaluator.evaluateMappings(Closure) (binding == null). Since production URLMappings.groovy evaluation typically goes through the Script/binding path (evaluateMappings(Resource/Class)), consider adding at least one test that evaluates a Script-based mappings resource/class and verifies group defaults inheritance there as well (otherwise the feature may pass tests but fail in real apps).

[Copilot]

The parameter order of this overload doesn't match the DSL call style shown in the PR description/tests (group "/api", namespace: ..., { ... }), which Groovy desugars to group(String, Map, Closure). With the current signature (group(Map, String, Closure)), this will result in a MissingMethodException at runtime. Consider changing the overload to group(String uri, Map<String,Object> defaults, Closure<?> mappingsClosure) (and adjust the recursion builder override accordingly).

[sbglasius]

@copilot Having a Map<String, Object> default first as arguments makes it a Named argument collector.

[testlens-app]

✅ All tests passed ✅

⚠️ TestLens detected flakiness ⚠️

Test Summary

Check	Project/Task	Test	Runs
CI - Groovy Joint Validation Build / build_grails	:grails-testing-support-dbcleanup-postgresql:test	PostgresDatabaseCleanerFunctionalSpec	❌ ✅

🏷️ Commit: 37658a2
▶️ Tests: 44111 executed
⚪️ Checks: 35/35 completed

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[matrei]

Looks solid and very useful, thank you @codeconsole !