From 2bc60f86219b00a9ba23efab8f4bb8de21e64e2a Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Wed, 14 Jan 2026 10:17:36 +0100 Subject: [PATCH] Enable Python Limited API for PL/Python on MSVC Previously, the Python Limited API was disabled on MSVC due to build failures caused by Meson not knowing to link against python3.lib instead of python3XX.lib when using the Limited API. This commit works around the Meson limitation by explicitly finding and linking against python3.lib on MSVC, and removes the preprocessor guard that was disabling the Limited API on MSVC in plpython.h. This requires python3.lib to be present in the Python installation, which is included when Python is installed. Author: Bryan Green Discussion: https://www.postgresql.org/message-id/flat/ee410de1-1e0b-4770-b125-eeefd4726a24%40eisentraut.org --- meson.build | 16 +++++++++++++++- src/pl/plpython/plpython.h | 4 ---- 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/meson.build b/meson.build index 555c94796c6..d8a701440da 100644 --- a/meson.build +++ b/meson.build @@ -1336,7 +1336,21 @@ if not pyopt.disabled() pm = import('python') python3_inst = pm.find_installation(python.full_path(), required: pyopt) if python3_inst.found() - python3_dep = python3_inst.dependency(embed: true, required: pyopt) + # On MSVC, link against python3.lib instead of python3XX.lib for + # Python Limited API. Right now, this is the only platform that + # needs this workaround. In the long run, Meson should handle + # this internally: + # . + if host_system == 'windows' and cc.get_id() == 'msvc' + python3_libdir = python3_inst.get_variable('prefix') / 'libs' + python3_lib = cc.find_library('python3', dirs: python3_libdir, required: pyopt) + python3_dep = declare_dependency( + include_directories: include_directories(python3_inst.get_variable('prefix') / 'include'), + dependencies: python3_lib, + ) + else + python3_dep = python3_inst.dependency(embed: true, required: pyopt) + endif # Remove this check after we depend on Meson >= 1.1.0 if not cc.check_header('Python.h', dependencies: python3_dep, required: pyopt, include_directories: postgres_inc) python3_dep = not_found_dep diff --git a/src/pl/plpython/plpython.h b/src/pl/plpython/plpython.h index d0745bb68af..595e4af7491 100644 --- a/src/pl/plpython/plpython.h +++ b/src/pl/plpython/plpython.h @@ -25,12 +25,8 @@ /* * Enable Python Limited API - * - * XXX currently not enabled on MSVC because of build failures */ -#if !defined(_MSC_VER) #define Py_LIMITED_API 0x03020000 -#endif /* * Pull in Python headers via a wrapper header, to control the scope of