JDK-8262003: Class.arrayType should not throw IllegalArgumentException

[Mandy Chung]

On 2/25/21 6:52 AM, Johannes Kuhn wrote:
> Thanks Mandy.
>
> Will amend the CSR to cover TypeDescriptor.OfField::arrayType as well, 
> and create a patch.
>
> Where should I put the tests?
> Didn't find any tests that exercise Class::arrayType in 
> test/jdk/java/lang/.
> Any wishes for tests that I should add w.r.t. Class::arrayType?
>

Yes, I suggest to put it under test/jdk/java/lang/Class/arrayType.

Mandy

> - Johannes
>
> On 24-Feb-21 20:54, Mandy Chung wrote:
>> Hi Johannes,
>>
>> Changing Class::arrayType to throw ISA makes sense to me.   I think 
>> `TypeDescriptor.ofField::arrayType` spec should also be updated to 
>> throw ISA to follow what JVM checks for array dimension because it's 
>> a static constraint check [1] (rather than a resolution error) for 
>> `anewarray` instruction to create an array no more than 255 dimensions.
>>
>> The CSR looks okay.  I agree that the compatibility risk is low.
>>
>> I'd like to review PR along with CSR together.
>>
>> Mandy
>> [1] 
>> https://docs.oracle.com/javase/specs/jvms/se15/html/jvms-4.html#jvms-4.9.1
>>
>> On 2/23/21 6:38 AM, Johannes Kuhn wrote:
>>> I want to learn about writing a CSR, and need a sponsor teaching me 
>>> the ropes.
>>>
>>> ----
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8262003
>>>
>>> Currently, Class.arrayType() will throw an IllegalArgumentException 
>>> if the maximum number of dimensions will be exceeded.
>>>
>>> Throwing an IllegalArgumentException from a method that doesn't take 
>>> an argument is, at least, strange.
>>>
>>> Therefore I would like to update the specification to allow this 
>>> method to throw an IllegalStateException, similar to what 
>>> ClassDesc.arrayType() does.
>>>
>>> ----
>>>
>>> The current plan is:
>>>
>>> * Create a CSR detailing the spec changes: 
>>> https://bugs.openjdk.java.net/browse/JDK-8262211
>>> * Surround the code with a try-catch block. Checking for the error 
>>> case is hard, and somewhat rare, so I think this is appropriate.
>>> * Copy the @throws javadoc line from ClassDesc.arrayType to 
>>> Class.arrayType
>>>
>>> But there are a few questions I would love to get the answer on:
>>>
>>> * Both Class.arrayType() and ClassDesc.arrayType() are specified by 
>>> TypeDescriptor.OfField. Should the specification of 
>>> TypeDescriptor.OfField.arrayType() changed as well?
>>> * Is the draft of my CSR fine? Should I add some details, or omit 
>>> things? Rephrase things?
>>>
>>> In advance, thanks for any support and feedback on this.
>>>
>>> - Johannes
>>