On Mon, 29 Jul 2024 19:36:31 GMT, Chen Liang <li...@openjdk.org> wrote:
> In #20241, it's noted that `ClassFile.verify` can return a mix-and-match of > mutable and immutable lists. > > Though the mutability of the list returned by `verify` has no particular > importance, as the mutable list is constructed on every call and does not > mutate the models, there are a few scenarios that they matter. Since > ClassFile API is designed with immutability in mind, we should change all > lists in ClassFile API to be immutable. > > Change summary: > - Critical scenarios where ClassFile API stores mutable objects: > - `ClassSignature.typeParameters` - keeps user mutable list > - `CompoundElement.elementList` - buffered models expose the underlying > mutable list > - `RuntimeInvisibleParameterAnnotationsAttribute`(and Visible) - keeps > users' nest mutable lists in an immutable list > - `StackMapFrameInfo.locals/stack` - keeps user mutable lists > - Optional scenarios to return immutable for good practice > - `ClassFile.verify` - mutable for full verified results > - `CompoundElement.elementList` - safe mutable for bound models > - Fail fast on user null `Attribute`s in `BoundAttribute.readAttributes` to > prevent unmodifiable list containing null > > I have also checked if we should stick with null-hostile `List.of` lists > instead of `Collections.unmodifiableList` lists; we are using > `unmodifiableList` (extensively in Signature parsing, for example) or other > ad-hoc immutable lists, so it is somewhat impractical and not meaningful to > enforce null-hostility. (See the list in JBS) > > These use sites are too sporadic so I made no unit tests. This pull request has now been integrated. Changeset: 6154a212 Author: Chen Liang <li...@openjdk.org> URL: https://git.openjdk.org/jdk/commit/6154a2129ba505b7163a1998792296827a056750 Stats: 30 lines in 11 files changed: 17 ins; 1 del; 12 mod 8336032: Enforce immutability of Lists used by ClassFile API Reviewed-by: asotona ------------- PR: https://git.openjdk.org/jdk/pull/20380
