Bug: correct HBase shell exit behavior to match code passed to exit
Status: Resolved | Priority: Critical | Resolution: Fixed
Created: 19/Nov/21 07:04
Affects Version/s: 2.4.8

The HBase shell has changed behavior in a way that breaks being able to exit properly.

Two example scripts to act as stand ins for hbase shell scripts to "do something simple then exit":
{code}
tmp % echo "list\nexit" > clean_exit.rb
tmp % echo "list\nexit 1" > error_exit.rb
{code}

Giving these two scripts is possible:

* passed as a cli argument
* via redirected stdin

Additionally the shell invocation can be:

* in the default compatibility mode
* with the "non interactive" flag that gives an exit code that reflects runtime errors

I'll post logs of the details as attachments but here are some tables of the exit codes.

The {{clean_exit.rb}} invocations ought to exit with success, exit code 0.

|| ||          1.4.14 || 1.7.1 || 2.0.6 || 2.1.9 || 2.2.7 || 2.3.7 || 2.4.8 || master ||
| cli, default |    0 |    0   |    0   |    0   |    0   |    0   |    1   |    1*   |
| cli, -n |         0 |    0   |    0   |    0   |    0   |    0   |    1   |  hang   |
| stdin, default |  0 |    0   |    0   |    0   |    0   |    0   |    0   |    0    |
| stdin, -n |       1 |    1   |    1   |    1   |    1   |    1   |    1*  |    1*   |

The {{error_exit.rb}} invocation should return a non-zero exit code, unless we're specifically trying to match a normal hbase shell session.

|| ||         1.4.14 || 1.7.1 || 2.0.6 || 2.1.9 || 2.2.7 || 2.3.7 || 2.4.8 || master ||
| cli, default |   1 |    1   |    1   |    1   |    1   |    1   |    1*  |    1*   |
| cli, -n |        1 |    1   |    1   |    1   |    1   |    1   |    1*  |  hang   |
| stdin, default | 0 |    0   |    0   |    0   |    0   |    0   |    0   |    0    |
| stdin, -n |      1 |    1   |    1   |    1   |    1   |    1   |    1*  |    1*   |

In cases marked with * the error details are different.

The biggest concern are the new-to-2.4 non-zero exit code when we should have a success and the hanging.

The former looks like this:

{code}
ERROR NoMethodError: private method `exit' called for nil:NilClass
{code}

The change in error details for the error exit script also shows this same detail.


This behavior appears to be a side effect of HBASE-11686. As far as I can tell, the IRB handling of 'exit' calls fail because we implement our own handling of sessoins rather than rely on the intended session interface. We never set a current session, and IRB's exit implementation presumes there will be one.

Running in debug shows this in a stacktrace:
{code}
Took 0.4563 seconds
ERROR NoMethodError: private method `exit' called for nil:NilClass
NoMethodError: private method `exit' called for nil:NilClass
                     irb_exit at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/irb/extend-command.rb:30
                     evaluate at stdin:2
                         eval at org/jruby/RubyKernel.java:1048
                     evaluate at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/irb/workspace.rb:85
                      eval_io at uri:classloader:/shell.rb:327
     each_top_level_statement at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/irb/ruby-lex.rb:246
                         loop at org/jruby/RubyKernel.java:1442
     each_top_level_statement at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/irb/ruby-lex.rb:232
                        catch at org/jruby/RubyKernel.java:1189
     each_top_level_statement at uri:classloader:/META-INF/jruby.home/lib/ruby/stdlib/irb/ruby-lex.rb:231
                      eval_io at uri:classloader:/shell.rb:326
  classpath:/jar-bootstrap.rb at classpath:/jar-bootstrap.rb:194
            exception_handler at uri:classloader:/shell.rb:339
                       <main> at classpath:/jar-bootstrap.rb:194
{code}

And in our version of IRB (0.9.6) [line 30 for extend-commands|https://github.com/ruby/irb/blob/v0.9.6/lib/irb/extend-command.rb#L30] corresponds to this code:
{code}
    # Quits the current irb context
    #
    # +ret+ is the optional signal or message to send to Context#exit
    #
    # Same as <code>IRB.CurrentContext.exit</code>.
    def irb_exit(ret = 0)
      irb_context.exit(ret)
    end
{code}