#1956: Fix MAVEN_ARGS bug

CHANGELOG.adoc

@@ -6,6 +6,7 @@ This file documents all notable changes to https://github.com/devonfw/IDEasy[IDE
 
 Release with new features and bugfixes:
 
+* https://github.com/devonfw/IDEasy/issues/1956[#1956]: Merging MAVEN_ARGS buggy
 * https://github.com/devonfw/IDEasy/issues/1846[#1846]: Fixed macOS Gatekeeper workaround
 * https://github.com/devonfw/IDEasy/issues/1906[#1906]: Fixed `ide uninstall` failing on macOS 
 * https://github.com/devonfw/IDEasy/issues/1985[#1985]: Fix path traversal errors when extracting ZIPs on Windows

cli/src/main/java/com/devonfw/tools/ide/environment/AbstractEnvironmentVariables.java

@@ -370,20 +370,34 @@ private static record ResolveContext(Object rootSrc, String rootValue, boolean l
   }
 
   /**
-   * Merges user value with default, avoiding duplication if default already contains the user value.
+   * Appends IDEasy's default to the user value, stripping conflicting user {@code -s <path>} and {@code -Dsettings.security=} arguments so the default wins
+   * without duplicates. An empty default leaves the user value untouched.
    *
-   * @param value the user-defined value
-   * @param defaultValue IDEasy's default value
-   * @return the merged value, or the user value if defaultValue is null or empty
+   * @param value the user-defined value.
+   * @param defaultValue IDEasy's default value.
+   * @return the merged value.
    */
   static String mergeWithDefault(String value, String defaultValue) {
     if (defaultValue == null || defaultValue.isEmpty()) {
       return value;
     }
-    if (defaultValue.contains(value)) {
-      return defaultValue;
+    StringBuilder sb = new StringBuilder();
+    String[] tokens = value.trim().split("\\s+");
+    for (int i = 0; i < tokens.length; i++) {
+      String token = tokens[i];
+      if (token.equals("-s")) {
+        i++;
+      } else if (!token.startsWith("-Dsettings.security=")) {
+        if (!sb.isEmpty()) {
+          sb.append(' ');
+        }
+        sb.append(token);
+      }
+    }
+    if (!sb.isEmpty()) {
+      sb.append(' ');
     }
-    return value + " " + defaultValue;
+    return sb.append(defaultValue).toString();
   }
 
 }

cli/src/test/java/com/devonfw/tools/ide/environment/EnvironmentVariablesTest.java

@@ -140,4 +140,24 @@ void testUserDefinedMavenArgsAlreadyInIdeasyDefaultsIsNotDuplicated() {
     assertThat(AbstractEnvironmentVariables.mergeWithDefault("-s /path/to/settings.xml", defaultValue)).isEqualTo(defaultValue);
     assertThat(AbstractEnvironmentVariables.mergeWithDefault("-s", defaultValue)).isEqualTo(defaultValue);
   }
+
+  /**
+   * Test that conflicting user-defined {@code -s} and {@code -Dsettings.security=} arguments are stripped and overridden by IDEasy's computed values (without
+   * duplication), while unrelated user arguments are preserved. See https://github.com/devonfw/IDEasy/issues/1956[#1956].
+   */
+  @Test
+  void testUserDefinedMavenArgsConflictingWithIdeasyDefaultsAreOverridden() {
+
+    String defaultValue = "-s /ide/settings.xml -Dsettings.security=/ide/settings-security.xml";
+    // user overrides both -s and -Dsettings.security= and keeps an unrelated argument
+    assertThat(AbstractEnvironmentVariables.mergeWithDefault("-Xmx8000m -s invalid/settings.xml -Dsettings.security=wrong", defaultValue))
+        .isEqualTo("-Xmx8000m " + defaultValue);
+    // user overrides only -Dsettings.security=
+    assertThat(AbstractEnvironmentVariables.mergeWithDefault("-Xmx8000m -Dsettings.security=wrong", defaultValue))
+        .isEqualTo("-Xmx8000m " + defaultValue);
+    // user has no conflicting argument, so all user arguments are kept
+    assertThat(AbstractEnvironmentVariables.mergeWithDefault("-T 4", defaultValue)).isEqualTo("-T 4 " + defaultValue);
+    // empty default leaves the user value untouched
+    assertThat(AbstractEnvironmentVariables.mergeWithDefault("-s invalid/settings.xml", "")).isEqualTo("-s invalid/settings.xml");
+  }
 }