HBASE-20270 Turned off command help that follows all errors in shell

Signed-off-by: Sean Busbey <busbey@apache.org>
(cherry picked from commit 152104ae1ba559c580ffaa083209fd2cfee1050b)

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

@@ -21,14 +21,25 @@ require 'shell/formatter'
 
 module Shell
   module Commands
+    # rubocop:disable Metrics/ClassLength
     class Command
       def initialize(shell)
         @shell = shell
       end
 
+      # gets the name that an operator would type into the shell
+
+      def command_name
+        klass_name = self.class.name.split('::').last
+        command = klass_name.gsub(/([^\^])([A-Z])/, '\1_\2').downcase
+        command
+      end
+
       # wrap an execution of cmd to catch hbase exceptions
       # cmd - command name to execute
       # args - arguments to pass to the command
+
+      # rubocop:disable Metrics/AbcSize
       def command_safe(debug, cmd = :command, *args)
         # Commands can overwrite start_time to skip time used in some kind of setup.
         # See count.rb for example.
@@ -48,7 +59,7 @@ module Shell
           puts "ERROR: #{rootCause}"
           puts "Backtrace: #{rootCause.backtrace.join("\n           ")}" if debug
           puts
-          puts help
+          puts "For usage try 'help \"#{command_name}\"'"
           puts
         else
           raise rootCause
@@ -58,6 +69,7 @@ module Shell
         @end_time ||= Time.now
         formatter.output_str(format('Took %.4f seconds', @end_time - @start_time))
       end
+      # rubocop:enable Metrics/AbcSize
 
       # Convenience functions to get different admins
       # Returns HBase::Admin ruby class.
@@ -162,5 +174,6 @@ module Shell
       # rubocop:enable Metrics/AbcSize, Metrics/CyclomaticComplexity
       # rubocop:enable Metrics/MethodLength, Metrics/PerceivedComplexity
     end
+    # rubocop:enable Metrics/ClassLength
   end
 end

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

@@ -34,6 +34,10 @@ EOF
       def command(id, table_cfs)
         replication_admin.append_peer_tableCFs(id, table_cfs)
       end
+
+      def command_name
+        'append_peer_tableCFs'
+      end
     end
   end
 end

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

@@ -35,6 +35,10 @@ EOF
       def command(id, table_cfs)
         replication_admin.remove_peer_tableCFs(id, table_cfs)
       end
+
+      def command_name
+        'remove_peer_tableCFs'
+      end
     end
   end
 end

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

@@ -46,6 +46,10 @@ module Shell
       def command(id, exclude_peer_table_cfs = nil)
         replication_admin.set_peer_exclude_tableCFs(id, exclude_peer_table_cfs)
       end
+
+      def command_name
+        'set_peer_exclude_tableCFs'
+      end
     end
   end
 end

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

@@ -34,6 +34,10 @@ module Shell
         puts peer_table_cfs
         peer_table_cfs
       end
+
+      def command_name
+        'show_peer_tableCFs'
+      end
     end
   end
 end

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

@@ -36,6 +36,24 @@ class ShellCommandsTest < Test::Unit::TestCase
   end
 end
 
+##
+# Tests whether erroneous command input suggests the right way to invoke
+# help method of the command
+class ShellCommandsErrorTest < Test::Unit::TestCase
+  include Hbase::TestHelpers
+
+  def setup
+    setup_hbase
+    @shell.interactive = true
+  end
+
+  define_test 'Erroneous command input should suggest help' do
+    name = :create
+    output = capture_stdout { @shell.command(name) }
+    assert_match(/For usage try 'help "#{name}"'/, output)
+  end
+end
+
 ##
 # Tests commands from the point of view of the shell to validate
 # that the error messages returned to the user are correct