From 476b35d4e311a3d77a550280d93393e518908b27 Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Tue, 20 Jan 2026 16:24:57 +0100 Subject: [PATCH] tests: Add a test C++ extension module While we already test that our headers are valid C++ using headerscheck, it turns out that the macros we define might still expand to invalid C++ code. This adds a minimal test extension that is compiled using C++ to test that it's actually possible to build and run extensions written in C++. Future commits will improve C++ compatibility of some of our macros and add usage of them to this extension make sure that they don't regress in the future. The test module is for the moment disabled when using MSVC. In particular, the use of designated initializers in PG_MODULE_MAGIC would require C++20, for which we are currently not set up. (GCC and Clang support it as extensions.) It is planned to fix this. Author: Jelte Fennema-Nio Discussion: https://www.postgresql.org/message-id/flat/CAGECzQR21OnnKiZO_1rLWO0-16kg1JBxnVq-wymYW0-_1cUNtg@mail.gmail.com --- configure | 8 ++++ configure.ac | 7 ++++ src/Makefile.global.in | 2 + src/makefiles/meson.build | 2 + src/test/modules/Makefile | 6 +++ src/test/modules/meson.build | 1 + src/test/modules/test_cplusplusext/.gitignore | 3 ++ src/test/modules/test_cplusplusext/Makefile | 26 ++++++++++++ src/test/modules/test_cplusplusext/README | 10 +++++ .../expected/test_cplusplusext.out | 7 ++++ .../modules/test_cplusplusext/meson.build | 42 +++++++++++++++++++ .../sql/test_cplusplusext.sql | 3 ++ .../test_cplusplusext--1.0.sql | 8 ++++ .../test_cplusplusext.control | 4 ++ .../test_cplusplusext/test_cplusplusext.cpp | 37 ++++++++++++++++ 15 files changed, 166 insertions(+) create mode 100644 src/test/modules/test_cplusplusext/.gitignore create mode 100644 src/test/modules/test_cplusplusext/Makefile create mode 100644 src/test/modules/test_cplusplusext/README create mode 100644 src/test/modules/test_cplusplusext/expected/test_cplusplusext.out create mode 100644 src/test/modules/test_cplusplusext/meson.build create mode 100644 src/test/modules/test_cplusplusext/sql/test_cplusplusext.sql create mode 100644 src/test/modules/test_cplusplusext/test_cplusplusext--1.0.sql create mode 100644 src/test/modules/test_cplusplusext/test_cplusplusext.control create mode 100644 src/test/modules/test_cplusplusext/test_cplusplusext.cpp diff --git a/configure b/configure index fb6a4914b0..04eeb1a741 100755 --- a/configure +++ b/configure @@ -760,6 +760,7 @@ CLANG LLVM_CONFIG AWK with_llvm +have_cxx ac_ct_CXX CXXFLAGS CXX @@ -4769,6 +4770,13 @@ ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $ ac_compiler_gnu=$ac_cv_c_compiler_gnu +if test -n "$ac_ct_CXX"; then + have_cxx=yes +else + have_cxx=no +fi + + # Check if it's Intel's compiler, which (usually) pretends to be gcc, # but has idiosyncrasies of its own. We assume icc will define # __INTEL_COMPILER regardless of CFLAGS. diff --git a/configure.ac b/configure.ac index d3febfe58f..13c75170f7 100644 --- a/configure.ac +++ b/configure.ac @@ -387,6 +387,13 @@ fi AC_PROG_CXX([$pgac_cxx_list]) +if test -n "$ac_ct_CXX"; then + have_cxx=yes +else + have_cxx=no +fi +AC_SUBST(have_cxx) + # Check if it's Intel's compiler, which (usually) pretends to be gcc, # but has idiosyncrasies of its own. We assume icc will define # __INTEL_COMPILER regardless of CFLAGS. diff --git a/src/Makefile.global.in b/src/Makefile.global.in index 371cd7eba2..947a2d79e2 100644 --- a/src/Makefile.global.in +++ b/src/Makefile.global.in @@ -280,6 +280,8 @@ PERMIT_DECLARATION_AFTER_STATEMENT = @PERMIT_DECLARATION_AFTER_STATEMENT@ PERMIT_MISSING_VARIABLE_DECLARATIONS = @PERMIT_MISSING_VARIABLE_DECLARATIONS@ CXXFLAGS = @CXXFLAGS@ +have_cxx = @have_cxx@ + LLVM_CPPFLAGS = @LLVM_CPPFLAGS@ LLVM_CFLAGS = @LLVM_CFLAGS@ LLVM_CXXFLAGS = @LLVM_CXXFLAGS@ diff --git a/src/makefiles/meson.build b/src/makefiles/meson.build index aa2f9a87b1..77f7a729cc 100644 --- a/src/makefiles/meson.build +++ b/src/makefiles/meson.build @@ -118,6 +118,8 @@ pgxs_kv = { 'FLEXFLAGS': ' '.join(flex_flags), 'LIBS': var_libs, + + 'have_cxx': have_cxx ? 'yes' : 'no', } if llvm.found() diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile index 4c6d56d97d..44c7163c1c 100644 --- a/src/test/modules/Makefile +++ b/src/test/modules/Makefile @@ -75,5 +75,11 @@ else ALWAYS_SUBDIRS += ldap_password_func endif +ifeq ($(have_cxx),yes) +SUBDIRS += test_cplusplusext +else +ALWAYS_SUBDIRS += test_cplusplusext +endif + $(recurse) $(recurse_always) diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build index 1b31c5b98d..2634a51993 100644 --- a/src/test/modules/meson.build +++ b/src/test/modules/meson.build @@ -21,6 +21,7 @@ subdir('test_bitmapset') subdir('test_bloomfilter') subdir('test_cloexec') subdir('test_copy_callbacks') +subdir('test_cplusplusext') subdir('test_custom_rmgrs') subdir('test_custom_stats') subdir('test_ddl_deparse') diff --git a/src/test/modules/test_cplusplusext/.gitignore b/src/test/modules/test_cplusplusext/.gitignore new file mode 100644 index 0000000000..913175ff6e --- /dev/null +++ b/src/test/modules/test_cplusplusext/.gitignore @@ -0,0 +1,3 @@ +/log/ +/results/ +/tmp_check/ diff --git a/src/test/modules/test_cplusplusext/Makefile b/src/test/modules/test_cplusplusext/Makefile new file mode 100644 index 0000000000..88cd440382 --- /dev/null +++ b/src/test/modules/test_cplusplusext/Makefile @@ -0,0 +1,26 @@ +# src/test/modules/test_cplusplusext/Makefile + +MODULE_big = test_cplusplusext +OBJS = \ + $(WIN32RES) \ + test_cplusplusext.o +PGFILEDESC = "test_cplusplusext - test C++ compatibility of PostgreSQL headers" + +EXTENSION = test_cplusplusext +DATA = test_cplusplusext--1.0.sql + +REGRESS = test_cplusplusext + +# Use C++ compiler for linking because this module includes C++ files +override COMPILER = $(CXX) $(CXXFLAGS) + +ifdef USE_PGXS +PG_CONFIG = pg_config +PGXS := $(shell $(PG_CONFIG) --pgxs) +include $(PGXS) +else +subdir = src/test/modules/test_cplusplusext +top_builddir = ../../../.. +include $(top_builddir)/src/Makefile.global +include $(top_srcdir)/contrib/contrib-global.mk +endif diff --git a/src/test/modules/test_cplusplusext/README b/src/test/modules/test_cplusplusext/README new file mode 100644 index 0000000000..8e4090edf0 --- /dev/null +++ b/src/test/modules/test_cplusplusext/README @@ -0,0 +1,10 @@ +test_cplusplusext - Test C++ Extension Compatibility +==================================================== + +This test module verifies that PostgreSQL headers and macros work +correctly when compiled with a C++ compiler. + +While PostgreSQL already tests that headers are syntactically valid +C++ using headerscheck, the macros defined in those headers might +still expand to invalid C++ code. This module catches such issues by +actually compiling and running an extension that's written in C++. diff --git a/src/test/modules/test_cplusplusext/expected/test_cplusplusext.out b/src/test/modules/test_cplusplusext/expected/test_cplusplusext.out new file mode 100644 index 0000000000..ab0b04b5c5 --- /dev/null +++ b/src/test/modules/test_cplusplusext/expected/test_cplusplusext.out @@ -0,0 +1,7 @@ +CREATE EXTENSION test_cplusplusext; +SELECT test_cplusplus_add(1, 2); + test_cplusplus_add +-------------------- + 3 +(1 row) + diff --git a/src/test/modules/test_cplusplusext/meson.build b/src/test/modules/test_cplusplusext/meson.build new file mode 100644 index 0000000000..d13210ca59 --- /dev/null +++ b/src/test/modules/test_cplusplusext/meson.build @@ -0,0 +1,42 @@ +# Copyright (c) 2025-2026, PostgreSQL Global Development Group + +if not have_cxx + subdir_done() +endif + +# Currently not supported, to be fixed. +if cc.get_id() == 'msvc' + subdir_done() +endif + +test_cplusplusext_sources = files( + 'test_cplusplusext.cpp', +) + +if host_system == 'windows' + test_cplusplusext_sources += rc_lib_gen.process(win32ver_rc, extra_args: [ + '--NAME', 'test_cplusplusext', + '--FILEDESC', 'test_cplusplusext - test C++ compatibility of PostgreSQL headers',]) +endif + +test_cplusplusext = shared_module('test_cplusplusext', + test_cplusplusext_sources, + kwargs: pg_test_mod_args, +) +test_install_libs += test_cplusplusext + +test_install_data += files( + 'test_cplusplusext.control', + 'test_cplusplusext--1.0.sql', +) + +tests += { + 'name': 'test_cplusplusext', + 'sd': meson.current_source_dir(), + 'bd': meson.current_build_dir(), + 'regress': { + 'sql': [ + 'test_cplusplusext', + ], + }, +} diff --git a/src/test/modules/test_cplusplusext/sql/test_cplusplusext.sql b/src/test/modules/test_cplusplusext/sql/test_cplusplusext.sql new file mode 100644 index 0000000000..a41682417a --- /dev/null +++ b/src/test/modules/test_cplusplusext/sql/test_cplusplusext.sql @@ -0,0 +1,3 @@ +CREATE EXTENSION test_cplusplusext; + +SELECT test_cplusplus_add(1, 2); diff --git a/src/test/modules/test_cplusplusext/test_cplusplusext--1.0.sql b/src/test/modules/test_cplusplusext/test_cplusplusext--1.0.sql new file mode 100644 index 0000000000..c54acb7682 --- /dev/null +++ b/src/test/modules/test_cplusplusext/test_cplusplusext--1.0.sql @@ -0,0 +1,8 @@ +/* src/test/modules/test_cplusplusext/test_cplusplusext--1.0.sql */ + +-- complain if script is sourced in psql, rather than via CREATE EXTENSION +\echo Use "CREATE EXTENSION test_cplusplusext" to load this file. \quit + +CREATE FUNCTION test_cplusplus_add(int4, int4) RETURNS int4 +AS 'MODULE_PATHNAME' +LANGUAGE C STRICT; diff --git a/src/test/modules/test_cplusplusext/test_cplusplusext.control b/src/test/modules/test_cplusplusext/test_cplusplusext.control new file mode 100644 index 0000000000..640a0a51f3 --- /dev/null +++ b/src/test/modules/test_cplusplusext/test_cplusplusext.control @@ -0,0 +1,4 @@ +comment = 'Test module for C++ extension compatibility' +default_version = '1.0' +module_pathname = '$libdir/test_cplusplusext' +relocatable = true diff --git a/src/test/modules/test_cplusplusext/test_cplusplusext.cpp b/src/test/modules/test_cplusplusext/test_cplusplusext.cpp new file mode 100644 index 0000000000..435937c00d --- /dev/null +++ b/src/test/modules/test_cplusplusext/test_cplusplusext.cpp @@ -0,0 +1,37 @@ +/*-------------------------------------------------------------------------- + * + * test_cplusplusext.cpp + * Test that PostgreSQL headers compile with a C++ compiler. + * + * This file is compiled with a C++ compiler to verify that PostgreSQL + * headers remain compatible with C++ extensions. + * + * Copyright (c) 2025-2026, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/test/modules/test_cplusplusext/test_cplusplusext.cpp + * + * ------------------------------------------------------------------------- + */ + +extern "C" { +#include "postgres.h" +#include "fmgr.h" + +PG_MODULE_MAGIC; + +PG_FUNCTION_INFO_V1(test_cplusplus_add); +} + +/* + * Simple function that returns the sum of two integers. This verifies that + * C++ extension modules can be loaded and called correctly at runtime. + */ +extern "C" Datum +test_cplusplus_add(PG_FUNCTION_ARGS) +{ + int32 a = PG_GETARG_INT32(0); + int32 b = PG_GETARG_INT32(1); + + PG_RETURN_INT32(a + b); +} -- 2.39.5