null and immutable list safe checks (#240)

* null and immutable list safe checks

CHANGELOG.md

@@ -1,3 +1,7 @@
+## [3.10.3] - 2022-04-16
+### Fixes
+* Potential exception when `set_ugi` has immutable list or null-value groups argument.
+
 ## [3.10.2] - 2022-04-19
 ### Changed
 * Caching `set_ugi` call in clients to prevent unnecessary calls to metastores.

waggle-dance-core/src/main/java/com/hotels/bdp/waggledance/client/HiveUgiArgs.java

@@ -15,19 +15,23 @@
  */
 package com.hotels.bdp.waggledance.client;
 
-import java.util.Collections;
+import java.util.ArrayList;
 import java.util.List;
 
 public class HiveUgiArgs {
 
-  public static final HiveUgiArgs WAGGLE_DANCE_DEFAULT = new HiveUgiArgs("waggledance", Collections.emptyList());
+  public static final HiveUgiArgs WAGGLE_DANCE_DEFAULT = new HiveUgiArgs("waggledance", null);
 
   private final String user;
   private final List<String> groups;
 
   public HiveUgiArgs(String user, List<String> groups) {
     this.user = user;
-    this.groups = groups;
+    if (groups == null) {
+      this.groups = new ArrayList<>();
+    } else {
+      this.groups = new ArrayList<>(groups);
+    }
   }
 
   public String getUser() {

waggle-dance-core/src/test/java/com/hotels/bdp/waggledance/client/HiveUgiArgsTest.java

@@ -0,0 +1,49 @@
+package com.hotels.bdp.waggledance.client;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Collections;
+
+import org.junit.Test;
+
+public class HiveUgiArgsTest {
+
+  @Test
+  public void groups() throws Exception {
+    HiveUgiArgs args = new HiveUgiArgs("user", new ArrayList<>());
+    assertThat("user", is(args.getUser()));
+    asssertThatListIsMutatable(args);
+  }
+
+  private void asssertThatListIsMutatable(HiveUgiArgs args) {
+    assertThat(args.getGroups().size(), is(0));
+    // List should be mutable, Hive code potentially mutates it.
+    args.getGroups().add("user");
+    assertThat(args.getGroups().size(), is(1));
+  }
+
+  @Test
+  public void groupDefaults() throws Exception {
+    HiveUgiArgs args = HiveUgiArgs.WAGGLE_DANCE_DEFAULT;
+    assertThat("waggledance", is(args.getUser()));
+    asssertThatListIsMutatable(args);
+  }
+
+  @Test
+  public void groupsImmutable() throws Exception {
+    HiveUgiArgs args = new HiveUgiArgs("user", Collections.emptyList());
+    assertThat("user", is(args.getUser()));
+    asssertThatListIsMutatable(args);
+  }
+
+  @Test
+  public void groupsNull() throws Exception {
+    HiveUgiArgs args = new HiveUgiArgs("user", null);
+    assertThat("user", is(args.getUser()));
+    assertTrue(args.getGroups().isEmpty());
+  }
+
+}