RFR: 8271356: Modify jdb to treat an empty command as a repeat of the previous command [v8]

[Jakob Cornell]

On Mon, 25 Oct 2021 22:21:54 GMT, Jakob Cornell <duke at openjdk.java.net> wrote:

>> This has been under discussion on and off for the past month or so on serviceability-dev, and I think a CSR request is required, so this may be a work in progress.
>> 
>> Notes on the patch:
>> 
>> - The `list` command previously marked a line in each listing with `=>`.  In a bare `list` this is the next line up for execution.  Previously when requesting a specific location (e.g. `list 5`) the requested line would be marked.  With the patch applied, `list` will only ever mark the next line up for execution.  This is consistent with the behavior of GDB and PDB (at least).
>> - `EOF` is printed when the repeat setting is on and a bare `list` command follows a listing containing the last source line.  This feature is from PDB; it's a somewhat softer message than the one for an explicit `list` request that's out of range.
>> - I don't speak Chinese or Japanese, so I've omitted localizations for the new messages in those locales.  However, I updated the help text in both to include the new commands, with the descriptions left empty for now.
>
> Jakob Cornell has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Restore update of copyright messages in resource files

Okay, I'll change those tests to use `failure`, and I'm okay doing that in the same PR.  Unfortunately I'm no longer able to build the JDK at `master`; I seem to be getting the same error that [this person did](https://mail.openjdk.java.net/pipermail/build-dev/2021-August/031907.html) in August.  Since the test classes depend on the JDK itself I'm not able to verify that the changes to the tests are correct (e.g. compile).  I suppose if others aren't seeing the same build error I could create that PR anyway and let someone else test the change.

Also, Daniel's failing Windows build seems to be caused by the command `2 2 up` only executing `up` once rather than 4 times, and I wasn't able to reproduce that JDB behavior on `master` on the Windows system I have access to.

On both of these items, I'm not sure how to proceed.

-------------

PR: https://git.openjdk.java.net/jdk/pull/5290