On Mon, 16 Mar 2026 22:38:52 GMT, Phil Race <[email protected]> wrote:

>> This fix updates DataBuffer subclasses to actually adhere to their stated 
>> specifications by rejecting certain invalid parameters for constructors and 
>> getters and setters.
>> A new egression test for each of the constructor and getter/setter cases is 
>> supplied.
>> 
>> No existing regression tests fail with this change, and standard demos work.
>> 
>> Problems caused by these changes are most likely to occur if the client has 
>> a bug such that 
>> - a client uses the constructors that accept an array and then supplies a 
>> "size" that is greater than the array.
>> - a client uses the constructors that accept an array and then supplies a 
>> "size" that is less than the array and then uses getter/setters that are 
>> within the array but outside the range specified by size. 
>> 
>> Since very few clients (and just one case in the JDK that I found) even use 
>> these array constructors the changes are unlikely to make a difference to 
>> clients.
>> 
>> The CSR is ready for review https://bugs.openjdk.org/browse/JDK-8378116
>
> Phil Race has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   8377568

I've updated for all comments to date.
I am going to propose a significant change (need first to implement and test) 
to make negative offsets illegal.
Briefly, the reason for this is that I've looked into 
https://bugs.openjdk.org/browse/JDK-4308987
It was a bug reported against JAI

"I am using JAI 1.0.2 "

Exception in thread "main" java.lang.ExceptionInInitializerError:
java.lang.IllegalArgumentException: Data offset(s) must be positive integer(s)
        at java.awt.image.DataBuffer.<init>(Unknown Source)
        at java.awt.image.DataBufferByte.<init>(Unknown Source)
        at javax.media.jai.LookupTableJAI.<init>(LookupTableJAI.java:115)

I've managed to locate the source for JAI 1.0.2 and the relevant code looks 
like this
    public LookupTableJAI(byte[] data, int offset) {
        this.data = new DataBufferByte(data, data.length, -offset);
    }

And that's why negative was needed.
Quite odd to my mind, whereas  in JAI 1.1.2 it looks like this 
   public LookupTableJAI(byte[] data, int offset) {
        this.initOffsets(1, offset);
        this.data = new DataBufferByte(data, data.length);
    }

So I don't think we need to worry any more about breaking JAI.
And some of the difficult to explain and problematic to implement cases go away.

Thoughts ?

-------------

PR Comment: https://git.openjdk.org/jdk/pull/29766#issuecomment-4071099555

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