RFR: 8334870: javac does not accept classfiles with certain permitted RuntimeVisibleParameterAnnotations and RuntimeInvisibleParameterAnnotations attributes.

[Chen Liang]

On Mon, 24 Jun 2024 15:06:01 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

> JVMS 4.7.18 and 4.7.19 say this about the entries in the RuntimeVisibleParameterAnnotations and RuntimeInvisibleParameterAnnotations attributes:
> 
>> The i'th entry in the parameter_annotations table may, but is not required to, correspond to the i'th parameter descriptor in the method descriptor (§4.3.3).
> 
> When reading classfiles, javac does not follow this specification (which puts no requirements on the number of entries in the attributes), but rather expects as many entries as the `MethodSymbol.type` has (which is either based in the `Signature` attribute, if present, or the method descritor, if `Signature` is not present).
> 
> This patch proposes to adjust javac to accept the attributes with any number of entries, implementing a number of heuristics to map the content of the entries in the attributes to the parameters. There are comments in the code explaining the heuristics.
> 
> javac will ignore the RuntimeVisibleParameterAnnotations and RuntimeInvisibleParameterAnnotations attributes it cannot handle with a warning.

test/langtools/tools/javac/annotations/parameter/ParameterAnnotations.java line 449:

> 447:     };
> 448: 
> 449:     private MethodTransform NO_SIGNATURE_NO_METHOD_PARAMETERS = (builder, element) -> {

Suggestion:

    private MethodTransform NO_SIGNATURE_NO_METHOD_PARAMETERS = MethodTransform.dropping(element -> element instanceof SignatureAttribute ||
            element instanceof MethodParametersAttribute);

Shortcuts like this.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19860#discussion_r1655628410