[hotfix] Fix drop database not working in terminal

amoro-format-mixed/amoro-mixed-spark/amoro-mixed-spark-3-common/src/main/java/org/apache/amoro/spark/SparkUnifiedCatalogBase.java

@@ -173,17 +173,29 @@ public void alterNamespace(String[] namespace, NamespaceChange... changes) {
     throw new UnsupportedOperationException("Cannot apply namespace change");
   }
 
-  @Override
-  public boolean dropNamespace(String[] namespace) {
+  public boolean dropNamespace(String[] namespace, boolean cascade)
+      throws NoSuchNamespaceException {
     String database = namespaceToDatabase(namespace);
+    if (!unifiedCatalog.databaseExists(database)) {
+      throw new NoSuchNamespaceException(namespace);
+    }
     List<TableIDWithFormat> tables = unifiedCatalog.listTables(database);
+    if (!tables.isEmpty() && !cascade) {
+      throw new IllegalStateException("Namespace '" + database + "' is non empty.");
+    }
+
     for (TableIDWithFormat id : tables) {
       unifiedCatalog.dropTable(database, id.getIdentifier().getTableName(), true);
     }
     unifiedCatalog.dropDatabase(database);
     return !unifiedCatalog.databaseExists(database);
   }
 
+  @Override
+  public boolean dropNamespace(String[] namespace) throws NoSuchNamespaceException {
+    return dropNamespace(namespace, false);
+  }
+
   @Override
   public Identifier[] listTables(String[] namespace) throws NoSuchNamespaceException {
     String database = namespaceToDatabase(namespace);

amoro-format-mixed/amoro-mixed-spark/amoro-mixed-spark-3-common/src/test/java/org/apache/amoro/spark/test/unified/UnifiedCatalogTestSuites.java

@@ -91,6 +91,9 @@ public void testTableFormats(TableFormat format, boolean sessionCatalog) {
     long count = sql(sqlText).count();
     Assertions.assertEquals(expect, count);
 
+    // create and drop namespace
+    testNamespaceWithSql();
+
     // visit sub tables.
     testVisitSubTable(format, sessionCatalog);
 
@@ -108,6 +111,17 @@ public void testTableFormats(TableFormat format, boolean sessionCatalog) {
     Assertions.assertFalse(unifiedCatalog().tableExists(target().database, target().table));
   }
 
+  private void testNamespaceWithSql() {
+    // Use SparkTestBase::sql method to test SparkUnifiedCatalog instead of CommonUnifiedCatalog.
+    String createDatabase = "CREATE DATABASE test_unified_catalog";
+    sql(createDatabase);
+    Assertions.assertTrue(unifiedCatalog().databaseExists("test_unified_catalog"));
+
+    String dropDatabase = "DROP DATABASE test_unified_catalog";
+    sql(dropDatabase);
+    Assertions.assertFalse(unifiedCatalog().databaseExists("test_unified_catalog"));
+  }
+
   private String pkDDL(TableFormat format) {
     if (TableFormat.MIXED_HIVE.equals(format) || TableFormat.MIXED_ICEBERG.equals(format)) {
       return ", primary key(id)";

amoro-format-mixed/amoro-mixed-spark/v3.3/amoro-mixed-spark-3.3/src/main/java/org/apache/amoro/spark/SparkUnifiedCatalog.java

@@ -22,7 +22,6 @@
 import org.apache.spark.sql.catalyst.analysis.NoSuchFunctionException;
 import org.apache.spark.sql.catalyst.analysis.NoSuchNamespaceException;
 import org.apache.spark.sql.catalyst.analysis.NoSuchTableException;
-import org.apache.spark.sql.catalyst.analysis.NonEmptyNamespaceException;
 import org.apache.spark.sql.connector.catalog.FunctionCatalog;
 import org.apache.spark.sql.connector.catalog.Identifier;
 import org.apache.spark.sql.connector.catalog.SupportsNamespaces;
@@ -69,26 +68,6 @@ public UnboundFunction loadFunction(Identifier ident) throws NoSuchFunctionExcep
     throw new NoSuchFunctionException(ident);
   }
 
-  /**
-   * Drop a namespace from the catalog with cascade mode, recursively dropping all objects within
-   * the namespace if cascade is true.
-   *
-   * <p>If the catalog implementation does not support this operation, it may throw {@link
-   * UnsupportedOperationException}.
-   *
-   * @param namespace a multi-part namespace
-   * @param cascade When true, deletes all objects under the namespace
-   * @return true if the namespace was dropped
-   * @throws NoSuchNamespaceException If the namespace does not exist (optional)
-   * @throws NonEmptyNamespaceException If the namespace is non-empty and cascade is false
-   * @throws UnsupportedOperationException If drop is not a supported operation
-   */
-  @Override
-  public boolean dropNamespace(String[] namespace, boolean cascade)
-      throws NoSuchNamespaceException, NonEmptyNamespaceException {
-    return false;
-  }
-
   /**
    * Load table metadata of a specific version by {@link Identifier identifier} from the catalog.
    *