RFR: 8311302: Allow for jlinking a custom runtime without packaged modules being present [v23]

[Magnus Ihse Bursie]

On Thu, 21 Mar 2024 15:27:06 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

>> make/Images.gmk line 131:
>> 
>>> 129:   # in FixPath call in order to avoid needing to use strip.
>>> 130:   RL_JIMAGE_PATH_ARG := $(call FixPath,$(JDK_LINK_OUTPUT_DIR)/lib/modules)
>>> 131:   RL_MOD_PATH_ARG := $(call FixPath,$(IMAGES_OUTPUTDIR)/jmods)
>> 
>> I'd much rather prefer to use strip and have proper space after commas. This is the approach taken elsewhere in the build system.
>> 
>> Suggestion:
>> 
>>   RL_JIMAGE_PATH_ARG := $(strip $(call FixPath, $(JDK_LINK_OUTPUT_DIR)/lib/modules))
>>   RL_MOD_PATH_ARG := $(strip $(call FixPath, $(IMAGES_OUTPUTDIR)/jmods))
>
> Thanks! This will also likely change. I'm thinking of just generating the diff file and putting it into `lib/` of the JDK image. That avoids needing to call this build-time only jlink plugin and this `FixPath` magic.

I see. I'm sorry if I did not fully understand how the ongoing discussions affected build source changes. 

Maybe I should just put the build part review of this PR on the backburner, and then you can ping me when you think you have a solution that will stick, and I can check how it holds up from a build perspective?

>> make/jdk/src/jdk.unsupported_jlink_runtime/share/classes/build/tools/runtimelink/CreateLinkableRuntimePlugin.java line 1:
>> 
>>> 1: /*
>> 
>> This file does not at all fit in with the pattern of other build tools, which are not module-based but instead live in packages `build.tools.*` in the `make/jdk/src/classes` directory. We will need to find a better arrangement for this.
>> 
>> First question, do this class really need to be in a separate module? (I'm afraid the answer is "yes" but I need to ask it anyway).
>
>> First question, do this class really need to be in a separate module? (I'm afraid the answer is "yes" but I need to ask it anyway).
> 
> Yes, because it uses the `Plugin` ServiceLoader extension using the boot ModuleLayer. But it's going to be a moot point because this'll get reworked due to concerns raised by @mlchung (having the plugin pipeline running when producing a linkable runtime jimage).

Ok, fine. Will the new solution still include a build-time only tool?

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PR Review Comment: https://git.openjdk.org/jdk/pull/14787#discussion_r1534149409
PR Review Comment: https://git.openjdk.org/jdk/pull/14787#discussion_r1534146496