RFR: 8333282: Better warning if newly build JDK fails to run

[Magnus Ihse Bursie]

On Thu, 30 May 2024 15:02:38 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

> If the newly built JDK fails to run ("DOA"), we will get a strange error message about jdk.compiler-gendata errors from make. The reason is not at all obvious.
> 
> Instead, we should make a simple check that we can actually use the new JDK before starting to use it for the first time, and report clearly to the user if this is not the case.

I had completely missed the `runnable-buildjdk` target. Yes, that was basically what I was trying to re-create.

It might be a race condition, but this particular place was always where I have hit problems first if there is an issue with the newly built JDK. It used to be `generate-link-opt-data`, but my guess is that this is further down the dependency chain now, since the symbol changes to use the current JDK.

I agree with your general analysis though. We should add the test to `runnable-buildjdk` (that's the easy part), and make sure we use it everywhere that we should (there I might need some help to look if I miss some places).

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PR Comment: https://git.openjdk.org/jdk/pull/19484#issuecomment-2140213983