RFR: 8237566: FindTests.gmk should only include existing TEST.ROOT files

[Erik Joelsson]

Hello Erik,

Looks good. Style wise I try to put closing braces for logical blocks on 
a new line, aligned with the opening brace. I think that helps making 
the already quite convoluted makefile logic a tad more readable.

/Erik

On 2020-02-13 04:44, Erik Helin wrote:
> Hi all,
>
> this small patch changes FindTest.gmk to only include TEST.ROOT files 
> that actually are present. The motivation for this change is that both 
> Git and Mercurial supports so called "sparse" checkouts [0][1] (still 
> somewhat experimental for both, but actively worked on). While 
> experimenting with these features I noticed that FindTests.gmk demands 
> that test/{jtreg,jdk,langtools,nashorn,jaxp}/TEST.ROOT are present 
> even if you are only trying to run e.g. `make hotspot`. This small 
> patch ensures that we only include TEST.ROOT files that actually exist 
> on disk.
>
> Webrev:
> https://cr.openjdk.java.net/~ehelin/8237566/00/
>
> Issue:
> https://bugs.openjdk.java.net/browse/JDK-8237566
>
> Testing:
> - Tier 1,2,3 on Linux, macOS, Windows (all x64)
>
> Thanks,
> Erik
>
> [0]: https://www.mercurial-scm.org/repo/hg/file/tip/hgext/sparse.py
> [1]: 
> https://github.blog/2020-01-17-bring-your-monorepo-down-to-size-with-sparse-checkout/
>
> PS. For the curious, I did manage to create a minimal working 
> directory for hotspot using git version 2.25 (with this patch applied):
>
> $ git clone https://github.com/openjdk/jdk --no-checkout
> $ cd jdk
> $ git sparse-checkout init --cone
> $ git sparse-checkout set make src/java.base src/hotspot
> $ curl 
> https://cr.openjdk.java.net/~ehelin/8237566/00/JDK-8237566.patch | git 
> apply
> $ bash configure
> $ make hotspot