Bug #18431 Down arrow doesn't return to current input

Description:
Using the down arrow fails to return to the current line of work if you have used the up arrow to access more than 1 history entry.

How to repeat:
* Open mysql command line client
* Enter a few commands
* Enter part of a command, do not execute
* Press up arrow several times
* Press down arrow several times

It is not possible to return to the line you were entering before hitting the up arrow to access the history.

Suggested fix:
It should always be possible to return to an incomplete line of work when using the mysql command line client.

I can confirm this bug on the 5.0.19 build for linux x86.  This is frustrating as looking back in the history to  reference an earlier query while constructing a new one is common.

Testcase:

1) connect to a server with the mysql command line client
2) type "select 1;" enter
3) type "select 2;" enter
4) type "select 3;" enter
5) up-arrow once (select 3), twice (select 2), three times (select 1)
6) down-arrow once (select 2), twice (select 3), three times (select 2)

On step 6 the third down arrow should have been a blank line not "select 2".

Bug is repeatable with today 5.2-BK sources as well.

Raising priority since this affects a customer and has a related support issue

This appears to be due to MySQL using an outdated version of readline. The source for 5.1.22-rc uses readline 5.0. This bug was fixed in 5.1. See bugfix 1b in http://tiswww.case.edu/php/chet/readline/CHANGES between 5.0 and 5.1.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/38057

ChangeSet@1.2555, 2007-11-19 14:38:08+01:00, df@pippilotta.erinye.com +43 -0
  Update readline to version 5.2. This fixes bug#18431.

Queued in -build.

Pushed into 5.0.54

Pushed into 5.1.23-rc

Pushed into 6.0.4-alpha

A note has been added to the 5.0.54, 5.1.23 and 6.0.4 changelog: 

The readline library has been updated to version 5.2. This addresses issues in the mysql client where history and editing within the client would fail to work as expected.

This is actually in 5.0.52, not in 5.0.54.

Moved 5.0.x changelog entry from 5.0.54 to 5.0.52.