Re: Use Python "Limited API" in PL/Python

On 1/2/2026 11:40 AM, Bryan Green wrote:
> On 1/15/2025 5:28 AM, Jakob Egger wrote:
>> On 14.01.2025, at 16:51, Jakob Egger <jakob(at)eggerapps(dot)at> wrote:
>>> I've tried to create a patch with this change. I'm attaching it to this message so that cfbot picks it up. (I was unable to reproduce the issue locally)
>>
>> Apologies, please disregard my last patch. It does not work.
>>
>> It looks like meson just can't build libraries that link with Python that use the limited API.
>>
>> My understanding of Meson is limited, so I am unsure how to best work around this limitation.
>>
>> I've spent two days trying to figure it out; I'm at the end of my wits.
>>
>> Best regards,
>> Jakob
> Hi Jakob and Peter,
>
> I've been working on enabling the Python Limited API on MSVC, which was
> disabled in the recent commit due to build failures.
>
> The issue is that Meson doesn't automatically link against python3.lib
> when using the Limited API. Meson's Python dependency always returns the
> version-specific library (python3XX.lib) regardless of whether
> limited api is defined. This appears to be a known Meson limitation:
> https://github.com/mesonbuild/meson/issues/13824
>
> Initially, I thought that maybe the library wasn't being installed, but
> that is not the case and the patch to our CI Windows MSVC image is not
> needed.
>
> I have a patch that works around this by manually constructing the
> Python dependency on MSVC to use python3.lib instead of python3XX.lib,
> using cc.find_library('python3') and building the dependency with the
> appropriate include directory. It passes CI when I push. I'll see what
> cfbot thinks.
>
> Still testing, but wanted to share progress and get feedback on the
> approach.
>

cfbot seems to be happy:
https://cirrus-ci.com/github/postgresql-cfbot/postgresql/cf%2F6369
--
Bryan Green
EDB: https://www.enterprisedb.com