Re: Decouple C++ support in Meson's PGXS from LLVM enablement

On Fri Nov 7, 2025 at 9:39 AM CST, Peter Eisentraut wrote:
> On 28.09.25 23:16, Tristan Partin wrote:
>>> Attached is a patch which decouples C++ support in PGXS from LLVM for
>>> a Meson-compiled Postgres.
>>>
>>> [0]: https://github.com/duckdb/pg_duckdb
>>
>> With PGConf NYC around the corner, I thought I would rebase the original
>> patch. Please find v2 attached, which applies on top of
>> b0fb2c6aa5a485e28210e13ae5536c1231b1261f[0] :D.
>
> This patch makes sense to me. But I wonder what the behavior should be
> if no C++ compiler is found. Because then you're back to the state
> you're started from, with the confusing make error. If you imagine a
> packager building postgresql in a minimal environment, and without llvm
> for some reason, then they would ship PGXS in that state without noticing.
>
> The AC_PROG_CXX macro sets CXX to g++ if no C++ compiler is found. Then
> a PGXS user would at least get an error message about g++ not found and
> they can fix it by installing it. Maybe we should do that under Meson too.
>
> An alternative would be to add some kind of build option or feature to
> enable C++ support explicitly.

Great idea. I need to re-spin the patch anyway after a discussion with
Jelte at NYC. I'll be sure to add this as well.

--
Tristan Partin
Databricks (https://databricks.com)