Proposed changes to empty command handling in JDB

[Alan Bateman]

On 05/08/2021 19:24, Chris Plummer wrote:
> Yes, it would be an "interesting project", but I'm not so sure we want 
> to put that level of effort into jdb. It's just not that widely used, 
> and is mainly there to demonstrate JDI use and to help test JDI, and 
> on occasion for very basic java debugging when the user doesn't care 
> to config an IDE to do such.

Yes, I assume most developers will just debug in the IDE. For the JDK 
then its usage is mostly for tests. It was originally intended as an 
example debugger but since it has been included in the JDK for a long 
time then it may be used for rudimentary debugging when there isn't 
anything else.

In any case, my main point is that if Jakob wants to put time into 
improving its usability then prototyping something that adds basic line 
editing and history support is potentially useful. I assume that would 
replace the TTY read/dispatch loop. If that were prototyped then it 
might give some sense on the effort to review, maintain, and be sure 
that the tests continue to run. I'm a bit dubious about changing jdb to 
have blank lines repeat like gdb. Hard to know if users of jdb expect 
that behavior and also it feels like basic history navigation would be 
better.

-Alan