On Tue, 28 Oct 2025 22:23:59 GMT, Chen Liang <[email protected]> wrote:
> ### Current Status > In core reflection, there are a few holes with the documentation on the type > conversions performed on the different setters. They generally follow this > process: > > 1. The Object-valued setters checks the destination type. If that type is > primitive, unbox the object. > 2. Perform identity or (primitive/reference, depending on destination type) > widening conversions. > > For each step, they can fail with IllegalArgumentException, which has been > the long standing behavior. > > Note that this process is more restrictive than the JLS 5.2 assignment > context, which allows boxing conversions, while the primitive reflective > setters consistently reject them. > > ### Problems > There are some problems with current specs: > 1. No mention that boxing is never done for primitive-typed setters > 2. Array.set missing description for the final identity or widening > conversion (reference or primitive) and the associated IAE condition > 3. Field.set misses the identity or widening in IAE clause (but mentioned in > main body) > 4. Field primitive setters incorrectly claim they are equivalent to > `set(instance, wrapper)` which is wrong due to lack of boxing conversion > 5. Field primitive setters refer to nonsense "unwrapping conversion" > > ### Solutions > 1. Make sure the unbox -> identity/widen process and the IAE conditoins are > present in both Field and Array.set > 2. Add that boxing is absent for all primitive setters > 3. Fix the Field primitive setters' "unwrapping conversion" to be "identity > or primitive widening conversion" as in Array primitive setters > 4. Qualify the Field primitive setters assertion with "if this field is of a > primitive type" to make it correct The class description allows for widening but specifies IAE if a narrowing conversion is needed. Should we expand this sentence? I'm also wondering about identity conversions in description of each method as I don't know if this will be understand by reader should links. ------------- PR Comment: https://git.openjdk.org/jdk/pull/28029#issuecomment-3461163146
