Обсуждение: [PATCH] meson: Update meson to enable building postgres as a subproject

Hi,

On 2025-08-30 04:18:05 +0000, Elliot Haisley wrote:
> While working on another project which needed libpq, I tried building postgres
> as a subproject to consume a recent version of libpq, and noticed it failed.
> I've put together a small patch that updates build files to not use
> the global source root, which allows postgres to be built as a meson subproject.

That makes sense.  I however can't apply it just now, the PG 18 code is frozen
until mid of the next week due to the release of 18rc1, and I think this
should be backpatched.

Greetings,

Andres Freund

On Sat Aug 30, 2025 at 9:55 AM CDT, Andres Freund wrote:
> Hi,
>
> On 2025-08-30 04:18:05 +0000, Elliot Haisley wrote:
>> While working on another project which needed libpq, I tried building postgres
>> as a subproject to consume a recent version of libpq, and noticed it failed.
>> I've put together a small patch that updates build files to not use
>> the global source root, which allows postgres to be built as a meson subproject.
>
> That makes sense.  I however can't apply it just now, the PG 18 code is frozen
> until mid of the next week due to the release of 18rc1, and I think this
> should be backpatched.

I also was working on a project that wanted to use libpq as a subproject
and came up with this independent but similar patch. I chose to develop
it against master.

I think that if we aim to support this workflow that we should add
a test in the tree somewhere. I am happy to develop one if someone
can direct me to a place where they would like it to live. In theory,
the test could even live as a meson test() in the source tree.

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

I also made a similar patch here
https://www.postgresql.org/message-id/F28283CF-AC9C-4930-9D84-56CD9E105504%40gmail.com.I pretty much did the same thing
butI also added postgres_inc to dependency because it cannot find postgres headers inside libpq’s headers. After
lookingat your patch i have few questions. Is meson.override_dependency(‘libpq’, libpq) really needed? It looks like it
doesnothing. In flex cmd args you removed —build-dir and —source-dir, was that necessary?  
Also when I was testing ur patch I couldn’t build libpq because of the problem with include directories of dependency
thatI mentioned. I attach the result patch with fix which only adds postgres_inc to libpq dependency
include_directoriesto your patch.  


> 3 янв. 2026 г., в 07:35, Tristan Partin <tristan@partin.io> написал(а):
>
> On Sat Aug 30, 2025 at 9:55 AM CDT, Andres Freund wrote:
>> Hi,
>>
>> On 2025-08-30 04:18:05 +0000, Elliot Haisley wrote:
>>> While working on another project which needed libpq, I tried building postgres
>>> as a subproject to consume a recent version of libpq, and noticed it failed.
>>> I've put together a small patch that updates build files to not use
>>> the global source root, which allows postgres to be built as a meson subproject.
>>
>> That makes sense.  I however can't apply it just now, the PG 18 code is frozen
>> until mid of the next week due to the release of 18rc1, and I think this
>> should be backpatched.
>
> I also was working on a project that wanted to use libpq as a subproject
> and came up with this independent but similar patch. I chose to develop
> it against master.
>
> I think that if we aim to support this workflow that we should add
> a test in the tree somewhere. I am happy to develop one if someone
> can direct me to a place where they would like it to live. In theory,
> the test could even live as a meson test() in the source tree.
>
> --
> Tristan Partin
> Databricks (https://databricks.com)
> <v1-0001-Add-subproject-support-to-the-meson-build.patch>

On Mon Jan 5, 2026 at 5:50 PM CST, Niyaz Hazigaleyev wrote:
> I also made a similar patch here
> https://www.postgresql.org/message-id/F28283CF-AC9C-4930-9D84-56CD9E105504%40gmail.com.
> I pretty much did the same thing but I also added postgres_inc to
> dependency because it cannot find postgres headers inside libpq’s
> headers. After looking at your patch i have few questions. Is
> meson.override_dependency(‘libpq’, libpq) really needed? It looks like
> it does nothing. In flex cmd args you removed —build-dir and
> —source-dir, was that necessary? Also when I was testing ur patch
> I couldn’t build libpq because of the problem with include directories
> of dependency that I mentioned. I attach the result patch with fix
> which only adds postgres_inc to libpq dependency include_directories
> to your patch.

I didn't have any problems with include directories, but it's possible
that my system corrupted my tests, as in my system includes supplemented
the missing subproject includes.

I removed the args from pgflex because they aren't used.

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