HBASE-19770 Separate command return values from interactive shells

Uses a new option to the shell to specify that return values are
unwanted instead of overloading the interactive option. Enable
return_values when the shell is non-interactive.

Includes addendum "Replace `if not` with `unless`"

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

bin/hirb.rb

@@ -59,12 +59,15 @@ Usage: shell [OPTIONS] [SCRIPTFILE [ARGUMENTS]]
  -n | --noninteractive          Do not run within an IRB session
                                 and exit with non-zero status on
                                 first error.
+ -r | --return-values           Include return values from commands
+                                executed in the shell.
 HERE
 found = []
 script2run = nil
 log_level = org.apache.log4j.Level::ERROR
 @shell_debug = false
 interactive = true
+return_values = false
 for arg in ARGV
   if arg == '-h' || arg == '--help'
     puts cmdline_help
@@ -78,6 +81,9 @@ for arg in ARGV
   elsif arg == '-n' || arg == '--noninteractive'
     interactive = false
     found.push(arg)
+  elsif arg == '-r' || arg == '--return-values'
+    return_values = true
+    found.push(arg)
   else
     # Presume it a script. Save it off for running later below
     # after we've set up some environment.
@@ -112,7 +118,7 @@ require 'shell/formatter'
 @hbase = Hbase::Hbase.new
 
 # Setup console
-@shell = Shell::Shell.new(@hbase, interactive)
+@shell = Shell::Shell.new(@hbase, interactive, return_values)
 @shell.debug = @shell_debug
 
 # Add commands to this namespace

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

@@ -71,14 +71,19 @@ module Shell
   class Shell
     attr_accessor :hbase
     attr_accessor :interactive
+    attr_accessor :return_values
     alias interactive? interactive
+    alias return_values? return_values
 
     @debug = false
     attr_accessor :debug
 
-    def initialize(hbase, interactive=true)
+    def initialize(hbase, interactive = true, return_values = !interactive)
       self.hbase = hbase
       self.interactive = interactive
+      self.return_values = return_values
+      # If we're in non-interactive mode, force return_values
+      self.return_values = true unless self.interactive
     end
 
     def hbase_admin
@@ -133,9 +138,12 @@ module Shell
       ::Shell.commands[command.to_s].new(self)
     end
 
-    #call the method 'command' on the specified command
+    # call the method 'command' on the specified command
+    # If return_values is false, then we suppress the return value. The command
+    # should have printed relevant output.
     def command(command, *args)
-      internal_command(command, :command, *args)
+      ret = internal_command(command, :command, *args)
+      ret if return_values
     end
 
     # call a specific internal method in the command instance

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

@@ -20,7 +20,7 @@ require 'shell'
 class NonInteractiveTest < Test::Unit::TestCase
   def setup
     @hbase = ::Hbase::Hbase.new($TEST_CLUSTER.getConfiguration)
-    @shell = Shell::Shell.new(@hbase, false)
+    @shell = Shell::Shell.new(@hbase, false, true)
   end
 
   define_test "Shell::Shell noninteractive mode should throw" do

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

@@ -43,7 +43,7 @@ module Hbase
 
     def setup_hbase
       hbase = ::Hbase::Hbase.new($TEST_CLUSTER.getConfiguration)
-      @shell = ::Shell::Shell.new(hbase)
+      @shell = ::Shell::Shell.new(hbase, interactive = false, return_values = true)
     end
     
     def shutdown