RFR: 8347007: --strip-debug removes parameter names included with -parameters [v3]

[Alan Bateman]

On Thu, 2 Oct 2025 05:40:49 GMT, Henry Jen <henryjen at openjdk.org> wrote:

>> Since parameters is an opt-in choice, it's more reasonable to consider that's desired information and make strip parameter names an opt-in choice as well.
>> 
>> This PR changes the default behavior of --strip-debug to keep parameter names when it's available. Add opt-in mechanism,
>> via the strip-java-debug-attributes plugin by using argument `--strip-java-debug-attributes=+parameter-names`.
>> 
>> The --strip-debug option is a little bit odd, as it's a main option as well as a plugin option to enable the DefaultStripDebugPlugin, which strip native debug information on platform support the feature, and strip java debug information. In this PR, we chose to support only one mechanism to enable strip parameter names, so we would disable the embed StripJavaDebugAttributesPlugin when StripJavaDebugAttributesPlugin is enabled.
>> 
>> The StripParameterNamesTest illustrate and verify parameter names use cases, mainly focus on argument processing and the parameter names. We didn't verify the regular debug info as that's covered by existing test.
>> 
>> -- Update
>> 
>> The latest change removed the support of strip parameter names, as the MethodParameters attribute is considered necessary attribute to fulfill Java Language Spec even though this attribute is considered optional by JVM spec.
>
> Henry Jen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   MethodParameters attribute should not be removed

It is surprising that the MethodParameters attribute is being stripped. I see ASM's SKIP_DEBUG is documented to skip this attribute, which explains why the re-implementation with the classfile API explicits drops it. So from a quick look, I think I think the change is doing the right thing. I will review closely soon.

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PR Comment: https://git.openjdk.org/jdk/pull/27566#issuecomment-3381887651