[PATCH v4] Use pending character state in IBM1390, IBM1399 character sets (CVE-2026-4046)

[Florian Weimer]

* Carlos O'Donell:

> On 4/10/26 3:57 PM, Florian Weimer wrote:
>> Follow the example in iso-2022-jp-3.c and use the __count state
>> variable to store the pending character.  This avoids restarting
>> the conversion if the output buffer ends between two 4-byte UCS-4
>> code points, so that the assert reported in the bug can no longer
>> happen.
>> Even though the fix is applied to ibm1364.c, the change is only
>> effective for the two HAS_COMBINED codecs for IBM1390, IBM1399.
>> The test case was mostly auto-generated using
>> claude-4.6-opus-high-thinking, and composer-2-fast shows up in the
>> log as well.  During review, gpt-5.4-xhigh flagged that the original
>> version of the test case was not exercising the new character
>> flush logic.
>
> I'm fine with your use of looser unstructured text, but I'd like
> a tag to find this with deterministic tooling
>
> e.g. "Assisted-by: Claude"
>
> Would that work for you?
>
> I don't actually care what we put in the tag so long as it is nominally
> the tool being used. The intent here is to indicate clearly that some
> of this was machine generated. Likewise in the future I'd like to use
> this tag to ask questions like "Did you reduce this from another set of
> project sources?" when someone says "Assisted-by: cvise" since that
> may carry license/copyright from the original work.

I'm going to send a v5 with Assisted-by:.

Thanks,
Florian