RFR: 8292983: ModuleReferenceImpl.computeHash should record algorithm for cache checks [v3]

[Alan Bateman]

On Fri, 26 Aug 2022 14:23:04 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Look at implementation and figure out what happens if you do:
>> 
>> 
>>  computeHash("SHA-1") = someHash;
>>  computeHash("SHA-256") = ...?
>> 
>> 
>> The caching method should actually check the algorithms match.
>> 
>> Not a bug at this point, since only use SHA-256 today, but this is a landmine ready to fire. 
>> 
>> Additional testing:
>>  - [x] Linux x86_64 release, `java/lang/module` tests
>
> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review comments

src/java.base/share/classes/jdk/internal/module/ModuleReferenceImpl.java line 69:

> 67:     // wrap the fields updated at the same time with a record, which carries
> 68:     // the implicit final-field semantics for its members.
> 69:     private record CachedHash(byte[] hash, String algorithm) {}

The comment still seems a bit excessive, maybe drop the last bit "which carries ..." as it is not needed here.

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PR: https://git.openjdk.org/jdk/pull/10044