[HBASE-20276] [shell] Revert shell REPL change and document

• Type: Sub-task
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 1.4.0, 2.0.0
• Fix Version/s: 1.4.4, 2.0.0
• Component/s: documentation, shell
• Hadoop Flags: Incompatible change

Release Note

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The HBase shell now behaves as it did prior to the changes that started in HBASE-15965. Namely, some shell commands return values that may be further manipulated within the shell's IRB session.

The command line option `--return-values` is no longer acted on by the shell since it now always behaves as it did when passed this parameter. Passing the option results in a harmless warning about this change.

Users who wish to maintain the behavior seen in the 1.4.0-1.4.2 releases of the HBase shell should refer to the section _irbrc_ in the reference guide for how to configure their IRB session to avoid echoing expression results to the console.

• Assignee: Sean Busbey
• Reporter: Sean Busbey
• Created: 24/Mar/18 04:19
• Updated: 24/Jun/22 18:05
• Resolved: 20/Apr/18 04:47

Description

Feedback from mdrob on HBASE-19158:

Shell:
HBASE-19770. There was another issue opened where this was identified as a problem so maybe the shape will change further, but I can't find it now.

New commentary from busbey:

This was a follow on to HBASE-15965. That change effectively makes it so none of our ruby wrappers can be used to build expressions in an interactive REPL. This is a pretty severe change (most of my tips on HBASE-15611 will break, I think).

I think we should

a) Have a DISCUSS thread, spanning dev@ and user@
b) based on the outcome of that thread, either default to the new behavior or the old behavior
c) if we keep the HBASE-15965 behavior as the default, flag it as incompatible, call it out in the hbase 2.0 upgrade section, and update docs (two examples: the output in the shell_exercises sections would be wrong, and the _table_variables section won't work)
d) In either case document the new flag in the ref guide

Issue Links

• blocks: HBASE-20263 Update stable release line to be based on branch-1.4
• is duplicated by: HBASE-20304 Flip default "return-values" in shell from false to true
• relates to: HBASE-20463 Fix breakage introduced on branch-1 by HBASE-20276 "[shell] Revert shell REPL change and document"
• supercedes: HBASE-19770 Add '--return-values' option to Shell to print return values of commands in interactive mode