Preserving Parameter Names

grails-gradle/plugins/src/main/groovy/org/grails/gradle/plugin/core/GrailsExtension.groovy

@@ -44,6 +44,7 @@ class GrailsExtension {
         this.project = project
         this.pluginDefiner = new PluginDefiner(project)
         this.indy = project.objects.property(Boolean).convention(false)
+        this.preserveParameterNames = project.objects.property(Boolean).convention(true)
     }
 
     /**
@@ -106,6 +107,18 @@ class GrailsExtension {
         this.indy.set(enabled)
     }
 
+    /**
+     * Preserve method parameter names in .class files (enables better IDE code completion for method parameters,
+     * reflection-based tools, bean introspection, etc.).
+     * Corresponds to groovyc `-parameters`.
+     * Default: true (See #13028)
+     */
+    final Property<Boolean> preserveParameterNames
+
+    void setPreserveParameterNames(boolean enabled) {
+        this.preserveParameterNames.set(enabled)
+    }
+
     DependencyHandler getPlugins() {
         if (pluginDefiner == null) {
             pluginDefiner = new PluginDefiner(project)

grails-gradle/plugins/src/main/groovy/org/grails/gradle/plugin/core/GrailsGradlePlugin.groovy

@@ -229,14 +229,18 @@ class GrailsGradlePlugin implements Plugin<Project> {
         // Configure indy and log status after evaluation so user's grails { } block has been applied
         project.afterEvaluate {
             boolean indyEnabled = grailsExtension?.indy?.getOrElse(false) ?: false
+            boolean preserveParameterNames = grailsExtension?.preserveParameterNames != null
+                ? grailsExtension.preserveParameterNames.getOrElse(true) : true
             project.tasks.withType(GroovyCompile).configureEach { GroovyCompile c ->
                 c.groovyOptions.optimizationOptions.indy = indyEnabled
+                c.groovyOptions.parameters = preserveParameterNames
             }
             if (!indyEnabled) {
                 project.logger.info('Grails: Groovy invokedynamic (indy) is disabled to improve performance (see issue #15293).')
                 project.logger.info('        To enable invokedynamic: grails { indy = true } in build.gradle')
             }
-        }
+            project.logger.info("Grails: Parameter name preservation is ${preserveParameterNames ? 'enabled' : 'disabled'} (-parameters flag). " +
+                "To change: grails { preserveParameterNames = ${!preserveParameterNames} } in build.gradle (see #13028)")        }
     }
 
     protected Closure<String> getGroovyCompilerScript(GroovyCompile compile, Project project) {

grails-gradle/plugins/src/test/groovy/org/grails/gradle/plugin/core/GrailsGradlePreserveParametersSpec.groovy

@@ -0,0 +1,38 @@
+package org.grails.gradle.plugin.core
+
+class GrailsGradlePreserveParametersSpec extends GradleSpecification {
+
+    def "Grails extension is created with default preserveParameterNames = true"() {
+        given:
+        setupTestResourceProject('preserve-params-default')
+
+        when:
+        def result = executeTask('inspectPreserveParam')
+
+        then:
+        result.output.contains("HAS_PRESERVE_PARAM_ENABLED=true")
+    }
+
+    def "preserveParameterNames can be configured to false via grails block"() {
+        given:
+        setupTestResourceProject('preserve-params-disabled')
+
+        when:
+        def result = executeTask('inspectPreserveParam')
+
+        then:
+        result.output.contains("HAS_PRESERVE_PARAM_ENABLED=false")
+    }
+
+    def "GroovyCompile tasks get parameters = true when preserveParameterNames is enabled"() {
+        given:
+        setupTestResourceProject('preserve-params-enabled')
+
+        when:
+        def result = executeTask('inspectPreserveParam')
+
+        then:
+        result.output.contains("HAS_PRESERVE_PARAM_ENABLED=true")
+    }
+
+}

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-default/build.gradle

@@ -0,0 +1,11 @@
+plugins {
+    id 'org.apache.grails.gradle.grails-app'
+}
+
+tasks.register('inspectPreserveParam') {
+    doLast {
+        def compileTasks = tasks.withType(GroovyCompile)
+        def paramsEnabled = compileTasks.every { it.groovyOptions.parameters }
+        println "HAS_PRESERVE_PARAM_ENABLED=${paramsEnabled}"
+    }
+}

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-default/gradle.properties

@@ -0,0 +1 @@
+grailsVersion=__PROJECT_VERSION__

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-default/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'test-preserve-params-default'

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-disabled/build.gradle

@@ -0,0 +1,15 @@
+plugins {
+    id 'org.apache.grails.gradle.grails-app'
+}
+
+grails {
+    preserveParameterNames = false
+}
+
+tasks.register('inspectPreserveParam') {
+    doLast {
+        def compileTasks = tasks.withType(GroovyCompile)
+        def paramsEnabled = compileTasks.every { it.groovyOptions.parameters }
+        println "HAS_PRESERVE_PARAM_ENABLED=${paramsEnabled}"
+    }
+}

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-disabled/gradle.properties

@@ -0,0 +1 @@
+grailsVersion=__PROJECT_VERSION__

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-disabled/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'test-preserve-params-disabled'

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-enabled/build.gradle

@@ -0,0 +1,15 @@
+plugins {
+    id 'org.apache.grails.gradle.grails-app'
+}
+
+grails {
+    preserveParameterNames = true
+}
+
+tasks.register('inspectPreserveParam') {
+    doLast {
+        def compileTasks = tasks.withType(GroovyCompile)
+        def paramsEnabled = compileTasks.every { it.groovyOptions.parameters }
+        println "HAS_PRESERVE_PARAM_ENABLED=${paramsEnabled}"
+    }
+}

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-enabled/gradle.properties

@@ -0,0 +1 @@
+grailsVersion=__PROJECT_VERSION__

grails-gradle/plugins/src/test/resources/test-projects/preserve-params-enabled/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'test-preserve-params-enabled'