Improve accessibility to the Gradle runtime compatibility from within toolbox infrastructure

subprojects/gradle-plugin-development/build.gradle

@@ -1,5 +1,3 @@
-import static dev.gradleplugins.GradleRuntimeCompatibility.*
-
 plugins {
     id 'org.jetbrains.kotlin.jvm' version "1.3.72"
     id 'toolboxbuild.publish'

subprojects/gradle-plugin-development/src/functionalTest/groovy/dev/gradleplugins/GradlePluginDevelopmentUnitTestingFunctionalTest.groovy

@@ -85,7 +85,6 @@ abstract class AbstractGradlePluginDevelopmentUnitTestingFunctionalTest extends
                 mavenCentral()
             }
 
-            import static ${GradleRuntimeCompatibility.canonicalName}.groovyVersionOf
             import ${GradleVersion.canonicalName}
 
             test {

subprojects/gradle-plugin-development/src/main/java/dev/gradleplugins/GradleRuntimeCompatibilitiesExtension.java

@@ -0,0 +1,75 @@
+package dev.gradleplugins;
+
+import org.gradle.api.JavaVersion;
+import org.gradle.api.Project;
+import org.gradle.api.provider.Provider;
+import org.gradle.util.GradleVersion;
+
+/**
+ * Gradle extension to access Gradle runtime information such as packaged version of Groovy and Kotlin.
+ * <p>
+ * All method takes a Gradle version in either of the following forms:
+ * <ul>
+ *     <li>{@link GradleVersion}: a Gradle version instance</li>
+ *     <li>String: any String parsable by {@link GradleVersion#version(String)}</li>
+ *     <li>{@link Provider} to any supported types</li>
+ *     <li>{@link Object#toString()} for any other instance</li>
+ * </ul>
+ */
+public interface GradleRuntimeCompatibilitiesExtension {
+    /**
+     * Returns the Groovy version packaged with the specified Gradle version.
+     *
+     * @param gradleVersion a specific Gradle version
+     * @return the Groovy version of the specified Gradle version, never null.
+     */
+    Provider<String> groovyVersionOf(Object gradleVersion);
+
+    /**
+     * Returns the minimum Java version of the specified Gradle version.
+     *
+     * @param gradleVersion a specific Gradle version
+     * @return the minimum Java version for the specified Gradle version, never null.
+     */
+    Provider<JavaVersion> minimumJavaVersionFor(Object gradleVersion);
+
+    /**
+     * Returns the Kotlin version packaged with the specified Gradle version.
+     * All Gradle version without Kotlin DSL support will return an empty value.
+     *
+     * @param gradleVersion a specific Gradle version
+     * @return the Kotlin version for the specified Gradle version, never null.
+     */
+    Provider<String> kotlinVersionOf(Object gradleVersion);
+
+    /**
+     * Returns the last patched Gradle version for the specified Gradle version.
+     * For example, passing Gradle version {@literal 6.2} would return {@literal 6.2.2}, the last patched version of {@literal 6.2.x}.
+     *
+     * @param gradleVersion  the Gradle version to find the last patched version, must not be null.
+     * @return the latest patched version for the specified version, never null
+     */
+    Provider<GradleVersion> lastPatchedVersionOf(Object gradleVersion);
+
+    /**
+     * Returns the last minor released Gradle version for the specified major Gradle version.
+     * For example, passing Gradle version {@literal 7.3} would return {@literal 7.6.4}, the last minor release of {@literal 7.x}.
+     * The function will return the last patched version as well.
+     *
+     * @param gradleVersion  the Gradle version to find the last minor release for, must not be null
+     * @return the latest minor version for the specified version, never null
+     */
+    Provider<GradleVersion> lastMinorReleaseOf(Object gradleVersion);
+
+    /**
+     * Returns the extension for this project.
+     * The user must apply one of the following plugins: {@literal dev.gradleplugins.gradle-plugin-base} or {@literal dev.gradleplugins.gradle-plugin-development}.
+     *
+     * @param project  the project to get the extension
+     * @return the extension, never null
+     */
+    static GradleRuntimeCompatibilitiesExtension forProject(Project project) {
+        assert project != null : "'project' must not be null";
+        return project.getExtensions().getByType(GradleRuntimeCompatibilitiesExtension.class);
+    }
+}