fix(mvn): pass developer root dir to maven tests

Author: simschla

lib/src/main/java/com/diffplug/spotless/generic/TestEnvVars.java

@@ -64,6 +64,9 @@ private static Stream<Path> candidateTestEnvLocations() {
 		if (System.getProperty("testenv.properties.path") != null) {
 			builder.add(Path.of(System.getProperty("testenv.properties.path")));
 		}
+		if (System.getProperty("spotlessProjectDir") != null) {
+			builder.add(Path.of(System.getProperty("spotlessProjectDir"), "testenv.properties"));
+		}
 		builder.add(
 				Path.of(System.getProperty("user.dir"), "testenv.properties"));
 		builder.add(

plugin-maven/build.gradle

@@ -55,6 +55,7 @@ dependencies {
 apply from: rootProject.file('gradle/special-tests.gradle')
 tasks.withType(Test).configureEach {
 	systemProperty 'spotlessMavenPluginVersion', project.version
+	systemProperty 'spotlessProjectDir', "${project.rootProject.projectDir}".toString()
 	dependsOn 'publishToMavenLocal'
 	dependsOn ':lib:publishToMavenLocal'
 	dependsOn ':lib-extra:publishToMavenLocal'

plugin-maven/src/main/java/com/diffplug/spotless/maven/generic/Idea.java

@@ -28,16 +28,16 @@ public class Idea implements FormatterStepFactory {
 	private String binaryPath;
 
 	@Parameter
-	private String configPath;
+	private String codeStyleSettingsPath;
 
 	@Parameter
-	private Boolean withDefaults = false;
+	private Boolean withDefaults = true;
 
 	@Override
 	public FormatterStep newFormatterStep(FormatterStepConfig config) {
 		return IdeaStep.newBuilder(config.getFileLocator().getBuildDir())
 				.setUseDefaults(withDefaults)
-				.setCodeStyleSettingsPath(configPath)
+				.setCodeStyleSettingsPath(codeStyleSettingsPath)
 				.setBinaryPath(binaryPath)
 				.build();
 	}

plugin-maven/src/test/java/com/diffplug/spotless/maven/MavenIntegrationHarness.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2024 DiffPlug
+ * Copyright 2016-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -213,9 +213,15 @@ protected void writePom(String[] executions, String[] configuration, String[] de
 	}
 
 	protected MavenRunner mavenRunner() throws IOException {
-		return MavenRunner.create()
+		MavenRunner mavenRunner = MavenRunner.create()
 				.withProjectDir(rootFolder())
 				.withRunner(runner);
+		System.getProperties().forEach((key, value) -> {
+			if (key instanceof String && ((String) key).startsWith("spotless") && value instanceof String) {
+				mavenRunner.withSystemProperty((String) key, (String) value);
+			}
+		});
+		return mavenRunner;
 	}
 
 	private static ProcessRunner runner;

plugin-maven/src/test/java/com/diffplug/spotless/maven/MavenRunner.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 DiffPlug
+ * Copyright 2016-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,8 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import com.diffplug.spotless.Jvm;
 import com.diffplug.spotless.ProcessRunner;
@@ -41,6 +43,7 @@ private MavenRunner() {}
 	private File projectDir;
 	private String[] args;
 	private Map<String, String> environment = new HashMap<>();
+	private Map<String, String> systemProperties = new HashMap<>();
 	private ProcessRunner runner;
 
 	public MavenRunner withProjectDir(File projectDir) {
@@ -64,12 +67,31 @@ public MavenRunner withRemoteDebug(int port) {
 		return this;
 	}
 
+	public MavenRunner withSystemProperty(String key, String value) {
+		systemProperties.put(key, value);
+		return this;
+	}
+
+	private Map<String, String> calculateEnvironment() {
+		Map<String, String> env = new HashMap<>(environment);
+		if (!systemProperties.isEmpty()) {
+			// add system properties as environment variables as MAVEN_OPTS or append if already there
+			String sysProps = systemProperties.entrySet().stream()
+					.map(entry -> String.format("-D%s=%s", entry.getKey(), entry.getValue()))
+					.collect(Collectors.joining(" "));
+			String mavenOpts = Stream.of(env.getOrDefault("MAVEN_OPTS", ""), sysProps)
+					.collect(Collectors.joining(" "));
+			env.put("MAVEN_OPTS", mavenOpts.trim());
+		}
+		return env;
+	}
+
 	private ProcessRunner.Result run() throws IOException, InterruptedException {
 		Objects.requireNonNull(projectDir, "Need to call withProjectDir() first");
 		Objects.requireNonNull(args, "Need to call withArguments() first");
 		// run Maven with the given args in the given directory
 		String argsString = "-e " + String.join(" ", Arrays.asList(args));
-		return runner.shellWinUnix(projectDir, environment, "mvnw " + argsString, "./mvnw " + argsString);
+		return runner.shellWinUnix(projectDir, calculateEnvironment(), "mvnw " + argsString, "./mvnw " + argsString);
 	}
 
 	/** Runs the command and asserts that exit code is 0. */