HBASE-20287 After cluster startup list_regions command fails on disabled table

Add is_enabled check for list_regions command

Signed-off-by: Mike Drob <mdrob@apache.org>

hbase-shell/src/main/ruby/shell/commands/list_regions.rb

@@ -50,6 +50,8 @@ EOF
           options = { SERVER_NAME => options }
         end
 
+        raise "Table #{table_name} must be enabled." unless admin.enabled?(table_name)
+
         size_hash = {}
         if cols.nil?
           size_hash = { 'SERVER_NAME' => 12, 'REGION_NAME' => 12, 'START_KEY' => 10, 'END_KEY' => 10, 'SIZE' => 5, 'REQ' => 5, 'LOCALITY' => 10 }

hbase-shell/src/test/ruby/hbase/admin_test.rb

@@ -319,6 +319,18 @@ module Hbase
       admin.truncate_preserve(@create_test_name, $TEST_CLUSTER.getConfiguration)
       assert_equal(splits, table(@create_test_name)._get_splits_internal())
     end
+
+    #-------------------------------------------------------------------------------
+
+    define_test "list_regions should fail for disabled table" do
+      drop_test_table(@create_test_name)
+      admin.create(@create_test_name, 'a')
+      command(:disable, @create_test_name)
+      assert(:is_disabled, @create_test_name)
+      assert_raise(RuntimeError) do
+        command(:list_regions, @create_test_name)
+      end
+    end
   end
 
   # Simple administration methods tests