Get rid of obtaining Gradle versions from projects (#2158)

Author: nedtwigg

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/FormatExtension.java

@@ -17,6 +17,7 @@
 
 import static com.diffplug.gradle.spotless.PluginGradlePreconditions.requireElementsNonNull;
 import static com.diffplug.gradle.spotless.SpotlessPluginRedirect.badSemver;
+import static com.diffplug.gradle.spotless.SpotlessPluginRedirect.badSemverOfGradle;
 import static java.util.Objects.requireNonNull;
 
 import java.io.File;
@@ -45,6 +46,7 @@
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.plugins.BasePlugin;
 import org.gradle.api.tasks.TaskProvider;
+import org.gradle.util.GradleVersion;
 
 import com.diffplug.common.base.Preconditions;
 import com.diffplug.spotless.FormatExceptionPolicyStrict;
@@ -452,11 +454,11 @@ public String apply(String unixNewlines) {
 	 */
 	public void custom(String name, FormatterFunc formatter) {
 		requireNonNull(formatter, "formatter");
-		if (badSemver(getProject()) < badSemver(SpotlessPlugin.VER_GRADLE_minVersionForCustom)) {
+		if (badSemverOfGradle() < badSemver(SpotlessPlugin.VER_GRADLE_minVersionForCustom)) {
 			throw new GradleException("The 'custom' method is only available if you are using Gradle "
 					+ SpotlessPlugin.VER_GRADLE_minVersionForCustom
 					+ " or newer, this is "
-					+ getProject().getGradle().getGradleVersion());
+					+ GradleVersion.current().getVersion());
 		}
 		addStep(FormatterStep.createLazy(name, () -> globalState, SerializedFunction.alwaysReturns(formatter)));
 	}

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/SpotlessPlugin.java

@@ -20,6 +20,7 @@
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
 import org.gradle.api.plugins.BasePlugin;
+import org.gradle.util.GradleVersion;
 
 import com.diffplug.spotless.Jvm;
 import com.diffplug.spotless.SpotlessCache;
@@ -33,8 +34,8 @@ public class SpotlessPlugin implements Plugin<Project> {
 
 	@Override
 	public void apply(Project project) {
-		if (SpotlessPluginRedirect.gradleIsTooOld(project)) {
-			throw new GradleException("Spotless requires Gradle " + VER_GRADLE_min + " or newer, this was " + project.getGradle().getGradleVersion());
+		if (SpotlessPluginRedirect.gradleIsTooOld()) {
+			throw new GradleException("Spotless requires Gradle " + VER_GRADLE_min + " or newer, this was " + GradleVersion.current().getVersion());
 		}
 		if (Jvm.version() < MINIMUM_JRE) {
 			throw new GradleException("Spotless requires JRE " + MINIMUM_JRE + " or newer, this was " + JavaVersion.current() + ".\n"

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/SpotlessPluginRedirect.java

@@ -21,16 +21,13 @@
 import org.gradle.api.GradleException;
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
+import org.gradle.util.GradleVersion;
 
 import com.diffplug.common.base.StringPrinter;
 
 public class SpotlessPluginRedirect implements Plugin<Project> {
 	private static final Pattern BAD_SEMVER = Pattern.compile("(\\d+)\\.(\\d+)");
 
-	static int badSemver(Project project) {
-		return badSemver(project.getGradle().getGradleVersion());
-	}
-
 	static int badSemver(String input) {
 		Matcher matcher = BAD_SEMVER.matcher(input);
 		if (!matcher.find() || matcher.start() != 0) {
@@ -41,18 +38,17 @@ static int badSemver(String input) {
 		return badSemver(Integer.parseInt(major), Integer.parseInt(minor));
 	}
 
+	static int badSemverOfGradle() {
+		return badSemver(GradleVersion.current().getVersion());
+	}
+
 	/** Ambiguous after 2147.483647.blah-blah */
 	private static int badSemver(int major, int minor) {
 		return major * 1_000_000 + minor;
 	}
 
-	static Boolean gradleIsTooOld;
-
-	static boolean gradleIsTooOld(Project project) {
-		if (gradleIsTooOld == null) {
-			gradleIsTooOld = badSemver(project) < badSemver(SpotlessPlugin.VER_GRADLE_min);
-		}
-		return gradleIsTooOld.booleanValue();
+	static boolean gradleIsTooOld() {
+		return badSemverOfGradle() < badSemver(SpotlessPlugin.VER_GRADLE_min);
 	}
 
 	@Override
@@ -76,8 +72,8 @@ public void apply(Project project) {
 				"",
 				"If you like the idea behind 'ratchetFrom', you should checkout spotless-changelog",
 				"https://github.com/diffplug/spotless-changelog");
-		if (gradleIsTooOld(project)) {
-			errorMsg = errorMsg.replace("To migrate:\n", "To migrate:\n- Upgrade Gradle to " + SpotlessPlugin.VER_GRADLE_min + " or newer (you're on " + project.getGradle().getGradleVersion() + ")\n");
+		if (gradleIsTooOld()) {
+			errorMsg = errorMsg.replace("To migrate:\n", "To migrate:\n- Upgrade Gradle to " + SpotlessPlugin.VER_GRADLE_min + " or newer (you're on " + GradleVersion.current().getVersion() + ")\n");
 		}
 		throw new GradleException(errorMsg);
 	}