RFR: 8317356: Test ClassFile API if it deals with nulls correctly across the whole API

[Chen Liang]

On Fri, 11 Oct 2024 15:57:50 GMT, Adam Sotona <asotona at openjdk.org> wrote:

>> Please review this patch that adds a test by @nizarbenalla to perform null checks across the ClassFile API. This is an updated version of #20556 that minimizes impact on our implementation code.
>> 
>> Notes:
>> 1. There's one change in `MethodHandleProxies` to explicitly use platform class loader instead of `null` for boot class loader. Tests work fine.
>> 2. The null check test uses the same set of classes as CorpusTest to make it suitable for tier 1.
>> 3. The test is not comprehensive; currently it is permissive toward IAE, because sometimes some substitution arguments are invalid, especially primitive ClassDesc or Opcode with wrong types.
>
> src/java.base/share/classes/jdk/internal/classfile/impl/ClassRemapperImpl.java line 276:
> 
>> 274:     @Override
>> 275:     public ClassDesc map(ClassDesc desc) {
>> 276:         if (desc == null) return null;
> 
> I'm not sure this won't break some use case.
> Here I would say null -> null mapping might be OK.

Makes sense. I will push the changes when you finish the review.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21458#discussion_r1797158151