Use Gradle user home directory for downloading biome, fixes diffplug#2187

Use the Gradle user home directory by default for the download directory for the biome executable.
Previously, the plugin tried to use Maven's home directory, which is not always accessible by a Gradle plugin.
According to the [Gradle docs](https://docs.gradle.org/current/kotlin-dsl/gradle/org.gradle.api.invocation/-gradle/get-gradle-user-home-dir.html),
the user home directory

> is used to cache downloaded resources, compiled build scripts and so on.

From that description, it seems to me to be the proper location for the biome executable.

Author: awa-xima

plugin-gradle/CHANGES.md

@@ -4,6 +4,9 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ## [Unreleased]
 
+* Use the Gradle user home directory by default for the download directory for the biome executable. Previously, the
+  plugin tried to use Maven's home directory, which is not always accessible by a Gradle plugin. ([#2187](https://github.com/diffplug/spotless/issues/2187))
+
 ## [7.0.0.BETA2] - 2024-08-25
 ### Changed
 * Support toning down sortPom logging. ([#2185](https://github.com/diffplug/spotless/pull/2185))

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

@@ -18,14 +18,12 @@
 import static java.util.Objects.requireNonNull;
 
 import java.io.File;
-import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.function.Consumer;
 
 import javax.annotation.Nullable;
 
 import org.gradle.api.Project;
-import org.gradle.api.artifacts.repositories.MavenArtifactRepository;
 
 import com.diffplug.spotless.FormatterStep;
 import com.diffplug.spotless.biome.BiomeFlavor;
@@ -208,23 +206,10 @@ protected void replaceStep() {
 	 * @return The directory for storing shared data.
 	 */
 	private File findDataDir() {
-		var currentRepo = project.getRepositories().stream().filter(r -> r instanceof MavenArtifactRepository)
-				.map(r -> (MavenArtifactRepository) r).filter(r -> "file".equals(r.getUrl().getScheme())).findAny()
-				.orElse(null);
-		// Temporarily add mavenLocal() repository to get its file URL
-		var localRepo = currentRepo != null ? (MavenArtifactRepository) currentRepo
-				: project.getRepositories().mavenLocal();
-		try {
-			// e.g. ~/.m2/repository/
-			var repoPath = Path.of(localRepo.getUrl());
-			var dataPath = repoPath.resolve("com").resolve("diffplug").resolve("spotless").resolve("spotless-data");
-			return dataPath.toAbsolutePath().toFile();
-		} finally {
-			// Remove mavenLocal() repository again if it was not part of the project
-			if (currentRepo == null) {
-				project.getRepositories().remove(localRepo);
-			}
-		}
+		// e.g. ~/.gradle/
+		var userHomeDir = project.getGradle().getGradleUserHomeDir().toPath();
+		var dataPath = userHomeDir.resolve("com").resolve("diffplug").resolve("spotless").resolve("spotless-data");
+		return dataPath.toAbsolutePath().toFile();
 	}
 
 	/**
@@ -247,7 +232,7 @@ private BiomeStep newBuilder() {
 	/**
 	 * Resolves the path to the Biome executable. When the path is only a file name,
 	 * do not perform any resolution and interpret it as a command that must be on
-	 * the user's path. Otherwise resolve the executable path against the project's
+	 * the user's path. Otherwise, resolve the executable path against the project's
 	 * base directory.
 	 *
 	 * @return The resolved path to the Biome executable.