SLCORE-690 Revert deletion of API class

backend/commons/src/main/java/org/sonarsource/sonarlint/core/commons/SonarLintUserHome.java

@@ -0,0 +1,44 @@
+/*
+ * SonarLint Core - Commons
+ * Copyright (C) 2016-2025 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonarsource.sonarlint.core.commons;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import javax.annotation.Nullable;
+
+public class SonarLintUserHome {
+
+  public static final String SONARLINT_USER_HOME_ENV = "SONARLINT_USER_HOME";
+
+  private SonarLintUserHome() {
+    // utility class, forbidden constructor
+  }
+
+  public static Path get() {
+    return home(System.getenv(SONARLINT_USER_HOME_ENV));
+  }
+
+  static Path home(@Nullable String slHome) {
+    if (slHome != null) {
+      return Paths.get(slHome);
+    }
+    return Paths.get(System.getProperty("user.home")).resolve(".sonarlint");
+  }
+}

backend/commons/src/test/java/org/sonarsource/sonarlint/core/commons/SonarLintUserHomeTests.java

@@ -0,0 +1,39 @@
+/*
+ * SonarLint Core - Commons
+ * Copyright (C) 2016-2025 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonarsource.sonarlint.core.commons;
+
+import java.nio.file.Paths;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class SonarLintUserHomeTests {
+
+  @Test
+  void env_setting_should_override_default_home() {
+    var customHome = "/custom/home";
+    assertThat(SonarLintUserHome.home(customHome)).isEqualTo(Paths.get(customHome));
+  }
+
+  @Test
+  void default_home_should_be_in_user_home() {
+    assertThat(SonarLintUserHome.get()).isEqualTo(Paths.get(System.getProperty("user.home")).resolve(".sonarlint"));
+  }
+}

backend/core/src/main/java/org/sonarsource/sonarlint/core/UserPaths.java

@@ -25,12 +25,11 @@
 import java.nio.file.Paths;
 import java.util.Optional;
 import javax.annotation.Nullable;
+import org.sonarsource.sonarlint.core.commons.SonarLintUserHome;
 import org.sonarsource.sonarlint.core.rpc.protocol.backend.initialize.InitializeParams;
 
 public class UserPaths {
 
-  private static final String SONARLINT_USER_HOME_ENV = "SONARLINT_USER_HOME";
-
   public static UserPaths from(InitializeParams initializeParams) {
     var userHome = computeUserHome(initializeParams.getSonarlintUserHome());
     createFolderIfNeeded(userHome);
@@ -45,11 +44,7 @@ static Path computeUserHome(@Nullable String clientUserHome) {
     if (clientUserHome != null) {
       return Paths.get(clientUserHome);
     }
-    String slHome = System.getenv(SONARLINT_USER_HOME_ENV);
-    if (slHome != null) {
-      return Paths.get(slHome);
-    }
-    return Paths.get(System.getProperty("user.home")).resolve(".sonarlint");
+    return SonarLintUserHome.get();
   }
 
   private static void createFolderIfNeeded(Path path) {