meson's in-tree libpq header search order vs -Dextra_include_dirs

From 0ba525115e6c6b7b9cadd73b3db9e26c77b8c1a2 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 14 Jul 2025 11:54:00 +1200
Subject: [PATCH] meson: Fix libpq header include order.

On systems using -Dextra_include_dir that happen to have a copy of libpq
installed there, it's important to put the libpq header search path
ahead of -Dextra_include_dir.  Reorder the dependencies to achieve that.
This matches the order used by configure.

Back-patch to 16, where meson arrived.

Reviewed-by:
Discussion: https://postgr.es/m/CA+hUKGKispvxLyrBn3=3mp0BB1N+RBYR5eE2guCOksnwEoOcPQ@mail.gmail.com
---
 contrib/dblink/meson.build                           | 2 +-
 contrib/oid2name/meson.build                         | 2 +-
 contrib/postgres_fdw/meson.build                     | 2 +-
 contrib/vacuumlo/meson.build                         | 2 +-
 src/backend/replication/libpqwalreceiver/meson.build | 2 +-
 src/bin/initdb/meson.build                           | 2 +-
 src/bin/pg_amcheck/meson.build                       | 2 +-
 src/bin/pg_basebackup/meson.build                    | 4 ++--
 src/bin/pg_combinebackup/meson.build                 | 2 +-
 src/bin/pg_dump/meson.build                          | 8 ++++----
 src/bin/pg_rewind/meson.build                        | 2 +-
 src/bin/pg_upgrade/meson.build                       | 2 +-
 src/bin/pgbench/meson.build                          | 2 +-
 src/bin/psql/meson.build                             | 2 +-
 src/bin/scripts/meson.build                          | 4 ++--
 src/fe_utils/meson.build                             | 2 +-
 src/interfaces/ecpg/ecpglib/meson.build              | 6 +++---
 src/interfaces/ecpg/include/meson.build              | 2 +-
 src/interfaces/libpq/test/meson.build                | 4 ++--
 src/test/isolation/meson.build                       | 4 ++--
 src/test/modules/libpq_pipeline/meson.build          | 2 +-
 src/test/modules/oauth_validator/meson.build         | 2 +-
 src/test/modules/test_escape/meson.build             | 2 +-
 src/test/modules/test_oat_hooks/meson.build          | 4 +++-
 src/test/regress/meson.build                         | 4 ++--
 25 files changed, 37 insertions(+), 35 deletions(-)

diff --git a/contrib/dblink/meson.build b/contrib/dblink/meson.build
index a19ce6cf4b9..28da26d3d45 100644
--- a/contrib/dblink/meson.build
+++ b/contrib/dblink/meson.build
@@ -13,7 +13,7 @@ endif
 dblink = shared_module('dblink',
   dblink_sources,
   kwargs: contrib_mod_args + {
-    'dependencies': contrib_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + contrib_mod_args['dependencies'],
   },
 )
 contrib_targets += dblink
diff --git a/contrib/oid2name/meson.build b/contrib/oid2name/meson.build
index 074f16acd72..dd958f00bdf 100644
--- a/contrib/oid2name/meson.build
+++ b/contrib/oid2name/meson.build
@@ -12,7 +12,7 @@ endif
 
 oid2name = executable('oid2name',
   oid2name_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 contrib_targets += oid2name
diff --git a/contrib/postgres_fdw/meson.build b/contrib/postgres_fdw/meson.build
index 5c11bc6496f..49012db1ba0 100644
--- a/contrib/postgres_fdw/meson.build
+++ b/contrib/postgres_fdw/meson.build
@@ -17,7 +17,7 @@ endif
 postgres_fdw = shared_module('postgres_fdw',
   postgres_fdw_sources,
   kwargs: contrib_mod_args + {
-    'dependencies': contrib_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + contrib_mod_args['dependencies'],
   },
 )
 contrib_targets += postgres_fdw
diff --git a/contrib/vacuumlo/meson.build b/contrib/vacuumlo/meson.build
index deee1d2832d..51e8fe9a325 100644
--- a/contrib/vacuumlo/meson.build
+++ b/contrib/vacuumlo/meson.build
@@ -12,7 +12,7 @@ endif
 
 vacuumlo = executable('vacuumlo',
   vacuumlo_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 contrib_targets += vacuumlo
diff --git a/src/backend/replication/libpqwalreceiver/meson.build b/src/backend/replication/libpqwalreceiver/meson.build
index 2150f31cfa3..5318a76e29d 100644
--- a/src/backend/replication/libpqwalreceiver/meson.build
+++ b/src/backend/replication/libpqwalreceiver/meson.build
@@ -14,7 +14,7 @@ libpqwalreceiver = shared_module('pqwalreceiver',
   libpqwalreceiver_sources,
   kwargs: pg_mod_args + {
     'name_prefix': 'lib',
-    'dependencies': pg_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + pg_mod_args['dependencies'],
   }
 )
 
diff --git a/src/bin/initdb/meson.build b/src/bin/initdb/meson.build
index 06958e370f3..b8584fe56de 100644
--- a/src/bin/initdb/meson.build
+++ b/src/bin/initdb/meson.build
@@ -21,7 +21,7 @@ initdb = executable('initdb',
   # shared library from a different PG version.  Define
   # USE_PRIVATE_ENCODING_FUNCS to ensure that that happens.
   c_args: ['-DUSE_PRIVATE_ENCODING_FUNCS'],
-  dependencies: [frontend_code, libpq, icu, icu_i18n],
+  dependencies: [libpq, frontend_code, icu, icu_i18n],
   kwargs: default_bin_args,
 )
 bin_targets += initdb
diff --git a/src/bin/pg_amcheck/meson.build b/src/bin/pg_amcheck/meson.build
index 316ea0d40b8..c8f792ff971 100644
--- a/src/bin/pg_amcheck/meson.build
+++ b/src/bin/pg_amcheck/meson.build
@@ -12,7 +12,7 @@ endif
 
 pg_amcheck = executable('pg_amcheck',
   pg_amcheck_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_amcheck
diff --git a/src/bin/pg_basebackup/meson.build b/src/bin/pg_basebackup/meson.build
index 3a7fc10eab0..b85ba465d47 100644
--- a/src/bin/pg_basebackup/meson.build
+++ b/src/bin/pg_basebackup/meson.build
@@ -7,7 +7,7 @@ common_sources = files(
   'walmethods.c',
 )
 
-pg_basebackup_deps = [frontend_code, libpq, lz4, zlib, zstd]
+pg_basebackup_deps = [libpq, frontend_code, lz4, zlib, zstd]
 pg_basebackup_common = static_library('libpg_basebackup_common',
   common_sources,
   dependencies: pg_basebackup_deps,
@@ -45,7 +45,7 @@ endif
 
 pg_createsubscriber = executable('pg_createsubscriber',
   pg_createsubscriber_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_createsubscriber
diff --git a/src/bin/pg_combinebackup/meson.build b/src/bin/pg_combinebackup/meson.build
index e80a4756a7f..04e09162d9b 100644
--- a/src/bin/pg_combinebackup/meson.build
+++ b/src/bin/pg_combinebackup/meson.build
@@ -17,7 +17,7 @@ endif
 
 pg_combinebackup = executable('pg_combinebackup',
   pg_combinebackup_sources,
-  dependencies: [frontend_code],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_combinebackup
diff --git a/src/bin/pg_dump/meson.build b/src/bin/pg_dump/meson.build
index 4a4ebbd8ec9..a079b6dfa92 100644
--- a/src/bin/pg_dump/meson.build
+++ b/src/bin/pg_dump/meson.build
@@ -22,7 +22,7 @@ pg_dump_common_sources = files(
 pg_dump_common = static_library('libpgdump_common',
   pg_dump_common_sources,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_code, libpq, lz4, zlib, zstd],
+  dependencies: [libpq, frontend_code, lz4, zlib, zstd],
   kwargs: internal_lib_args,
 )
 
@@ -42,7 +42,7 @@ endif
 pg_dump = executable('pg_dump',
   pg_dump_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_dump
@@ -61,7 +61,7 @@ endif
 pg_dumpall = executable('pg_dumpall',
   pg_dumpall_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_dumpall
@@ -80,7 +80,7 @@ endif
 pg_restore = executable('pg_restore',
   pg_restore_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_restore
diff --git a/src/bin/pg_rewind/meson.build b/src/bin/pg_rewind/meson.build
index 36171600cca..f2790246b23 100644
--- a/src/bin/pg_rewind/meson.build
+++ b/src/bin/pg_rewind/meson.build
@@ -21,7 +21,7 @@ endif
 
 pg_rewind = executable('pg_rewind',
   pg_rewind_sources,
-  dependencies: [frontend_code, libpq, lz4, zstd],
+  dependencies: [libpq, frontend_code, lz4, zstd],
   c_args: ['-DFRONTEND'], # needed for xlogreader et al
   kwargs: default_bin_args,
 )
diff --git a/src/bin/pg_upgrade/meson.build b/src/bin/pg_upgrade/meson.build
index ac992f0d14b..8aefaeea91f 100644
--- a/src/bin/pg_upgrade/meson.build
+++ b/src/bin/pg_upgrade/meson.build
@@ -28,7 +28,7 @@ endif
 pg_upgrade = executable('pg_upgrade',
   pg_upgrade_sources,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_upgrade
diff --git a/src/bin/pgbench/meson.build b/src/bin/pgbench/meson.build
index a2a909a8442..de013cc9827 100644
--- a/src/bin/pgbench/meson.build
+++ b/src/bin/pgbench/meson.build
@@ -27,7 +27,7 @@ endif
 
 pgbench = executable('pgbench',
   pgbench_sources,
-  dependencies: [frontend_code, libpq, thread_dep],
+  dependencies: [libpq, frontend_code, thread_dep],
   include_directories: include_directories('.'),
   c_pch: pch_postgres_fe_h,
   c_args: host_system == 'windows' ? ['-DFD_SETSIZE=1024'] : [],
diff --git a/src/bin/psql/meson.build b/src/bin/psql/meson.build
index f795ff28271..4fe711177af 100644
--- a/src/bin/psql/meson.build
+++ b/src/bin/psql/meson.build
@@ -58,7 +58,7 @@ psql = executable('psql',
   psql_sources,
   c_pch: pch_postgres_fe_h,
   include_directories: include_directories('.'),
-  dependencies: [frontend_code, libpq, readline],
+  dependencies: [libpq, frontend_code, readline],
   kwargs: default_bin_args,
 )
 bin_targets += psql
diff --git a/src/bin/scripts/meson.build b/src/bin/scripts/meson.build
index 80df7c33257..90517dd9a10 100644
--- a/src/bin/scripts/meson.build
+++ b/src/bin/scripts/meson.build
@@ -2,7 +2,7 @@
 
 scripts_common = static_library('libscripts_common',
   files('common.c'),
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: internal_lib_args,
 )
 
@@ -29,7 +29,7 @@ foreach binary : binaries
   binary = executable(binary,
     binary_sources,
     link_with: [scripts_common],
-    dependencies: [frontend_code, libpq],
+    dependencies: [libpq, frontend_code],
     kwargs: default_bin_args,
   )
   bin_targets += binary
diff --git a/src/fe_utils/meson.build b/src/fe_utils/meson.build
index a18cbc939e4..7487869f1cf 100644
--- a/src/fe_utils/meson.build
+++ b/src/fe_utils/meson.build
@@ -31,7 +31,7 @@ fe_utils_sources += psqlscan
 fe_utils = static_library('libpgfeutils',
   fe_utils_sources + generated_headers,
   c_pch: pch_postgres_fe_h,
-  include_directories: [postgres_inc, libpq_inc],
+  include_directories: [libpq_inc, postgres_inc],
   c_args: host_system == 'windows' ? ['-DFD_SETSIZE=1024'] : [],
   dependencies: frontend_common_code,
   kwargs: default_lib_args,
diff --git a/src/interfaces/ecpg/ecpglib/meson.build b/src/interfaces/ecpg/ecpglib/meson.build
index 8f478c6a73e..fb7d33d2a0e 100644
--- a/src/interfaces/ecpg/ecpglib/meson.build
+++ b/src/interfaces/ecpg/ecpglib/meson.build
@@ -30,7 +30,7 @@ ecpglib_st = static_library('libecpg',
   include_directories: ecpglib_inc,
   c_args: ecpglib_c_args,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_stlib_code, thread_dep, libpq],
+  dependencies: [libpq, frontend_stlib_code, thread_dep],
   link_with: [ecpg_pgtypes_st],
   kwargs: default_lib_args,
 )
@@ -41,7 +41,7 @@ ecpglib_so = shared_library('libecpg',
   include_directories: ecpglib_inc,
   c_args: ecpglib_c_args,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_shlib_code, libpq, thread_dep],
+  dependencies: [libpq, frontend_shlib_code, thread_dep],
   link_with: ecpg_pgtypes_so,
   soversion: host_system != 'windows' ? '6' : '',
   darwin_versions: ['6', '6.' + pg_version_major.to_string()],
@@ -58,7 +58,7 @@ pkgconfig.generate(
   url: pg_url,
   libraries: ecpglib_so,
   libraries_private: [frontend_stlib_code, thread_dep],
-  requires_private: ['libpgtypes', 'libpq'],
+  requires_private: ['libpq', 'libpgtypes'],
 )
 
 subdir('po', if_found: libintl)
diff --git a/src/interfaces/ecpg/include/meson.build b/src/interfaces/ecpg/include/meson.build
index a6541e1a686..133ebe2f11f 100644
--- a/src/interfaces/ecpg/include/meson.build
+++ b/src/interfaces/ecpg/include/meson.build
@@ -1,6 +1,6 @@
 # Copyright (c) 2022-2025, PostgreSQL Global Development Group
 
-ecpg_inc = include_directories('.')
+ecpg_inc = [libpq_inc, include_directories('.')]
 
 ecpg_conf_keys = [
   'SIZEOF_LONG',
diff --git a/src/interfaces/libpq/test/meson.build b/src/interfaces/libpq/test/meson.build
index 07a5facc321..75d2012ba17 100644
--- a/src/interfaces/libpq/test/meson.build
+++ b/src/interfaces/libpq/test/meson.build
@@ -14,7 +14,7 @@ endif
 
 libpq_test_deps += executable('libpq_uri_regress',
   libpq_uri_regress_sources,
-  dependencies: [frontend_no_fe_utils_code, libpq],
+  dependencies: [libpq, frontend_no_fe_utils_code],
   kwargs: default_bin_args + {
     'install': false,
   }
@@ -33,7 +33,7 @@ endif
 
 libpq_test_deps += executable('libpq_testclient',
   libpq_testclient_sources,
-  dependencies: [frontend_no_fe_utils_code, libpq],
+  dependencies: [libpq, frontend_no_fe_utils_code],
   kwargs: default_bin_args + {
     'install': false,
   }
diff --git a/src/test/isolation/meson.build b/src/test/isolation/meson.build
index a180e4e2741..660b11eff8b 100644
--- a/src/test/isolation/meson.build
+++ b/src/test/isolation/meson.build
@@ -35,7 +35,7 @@ pg_isolation_regress = executable('pg_isolation_regress',
   isolation_sources,
   c_args: pg_regress_cflags,
   include_directories: pg_regress_inc,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/isolation',
   },
@@ -52,7 +52,7 @@ endif
 isolationtester = executable('isolationtester',
   isolationtester_sources,
   include_directories: include_directories('.'),
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/isolation',
   },
diff --git a/src/test/modules/libpq_pipeline/meson.build b/src/test/modules/libpq_pipeline/meson.build
index 3fd70a04a38..83201111ca3 100644
--- a/src/test/modules/libpq_pipeline/meson.build
+++ b/src/test/modules/libpq_pipeline/meson.build
@@ -12,7 +12,7 @@ endif
 
 libpq_pipeline = executable('libpq_pipeline',
   libpq_pipeline_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   },
diff --git a/src/test/modules/oauth_validator/meson.build b/src/test/modules/oauth_validator/meson.build
index a6f937fd7d7..2cd5c4cd537 100644
--- a/src/test/modules/oauth_validator/meson.build
+++ b/src/test/modules/oauth_validator/meson.build
@@ -60,7 +60,7 @@ endif
 
 oauth_hook_client = executable('oauth_hook_client',
   oauth_hook_client_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   },
diff --git a/src/test/modules/test_escape/meson.build b/src/test/modules/test_escape/meson.build
index a21341d5067..04fd0be0889 100644
--- a/src/test/modules/test_escape/meson.build
+++ b/src/test/modules/test_escape/meson.build
@@ -10,7 +10,7 @@ endif
 
 test_escape = executable('test_escape',
   test_escape_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   }
diff --git a/src/test/modules/test_oat_hooks/meson.build b/src/test/modules/test_oat_hooks/meson.build
index 1e600b0f4c7..6f0c4afd433 100644
--- a/src/test/modules/test_oat_hooks/meson.build
+++ b/src/test/modules/test_oat_hooks/meson.build
@@ -12,7 +12,9 @@ endif
 
 test_oat_hooks = shared_module('test_oat_hooks',
   test_oat_hooks_sources,
-  kwargs: pg_test_mod_args,
+  kwargs: pg_test_mod_args + {
+	'dependencies': [libpq] + pg_test_mod_args['dependencies'],
+  }
 )
 test_install_libs += test_oat_hooks
 
diff --git a/src/test/regress/meson.build b/src/test/regress/meson.build
index 1da9e9462a9..99f402f49a8 100644
--- a/src/test/regress/meson.build
+++ b/src/test/regress/meson.build
@@ -2,7 +2,7 @@
 
 # also used by isolationtester and ecpg tests
 pg_regress_c = files('pg_regress.c')
-pg_regress_inc = include_directories('.')
+pg_regress_inc = [libpq_inc, include_directories('.')]
 
 regress_sources = pg_regress_c + files(
   'pg_regress_main.c'
@@ -30,7 +30,7 @@ endif
 pg_regress = executable('pg_regress',
   regress_sources,
   c_args: pg_regress_cflags,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/regress',
   },
-- 
2.50.1

From 25d830c8dab734349758286605bd2d1de643ed86 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Sat, 1 Nov 2025 17:10:11 +1300
Subject: [PATCH v2] meson: Fix libpq header inclusion order.

Make sure that libpq_inc always comes before postgres_inc, since the
latter includes -Dextra_include_dirs.  We want to find the in-tree libpq
headers before any copy that might happen to be installed on the system
in that location.

Discussion: https://postgr.es/m/CA%2BhUKGJU9kJiSTwxvrDxqrDFw8VvsX9ZbZRL%3DqP%3DKXuFX_XH2A%40mail.gmail.com
---
 meson.build                             | 7 ++++++-
 src/fe_utils/meson.build                | 2 +-
 src/interfaces/ecpg/preproc/meson.build | 2 +-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/meson.build b/meson.build
index 0f61ff6a700..2017b76a836 100644
--- a/meson.build
+++ b/meson.build
@@ -3301,7 +3301,12 @@ subdir('src/interfaces/libpq-oauth')
 
 # for frontend binaries
 frontend_code = declare_dependency(
-  include_directories: [postgres_inc],
+  # Not all code that depends on frontend_code also depends on libpq, but by
+  # pulling in its headers before postgres_inc we avoid exposing headers from a
+  # system-installed copy of libpq found in -Dextra_include_dirs, without
+  # requiring every frontend binary that depends on both to declare them in the
+  # right order.
+  include_directories: [libpq_inc, postgres_inc],
   link_with: [fe_utils, common_static, pgport_static],
   sources: generated_headers_stamp,
   dependencies: [os_deps, libintl],
diff --git a/src/fe_utils/meson.build b/src/fe_utils/meson.build
index ddac3c3a658..0a65b973779 100644
--- a/src/fe_utils/meson.build
+++ b/src/fe_utils/meson.build
@@ -32,7 +32,7 @@ fe_utils_sources += psqlscan
 fe_utils = static_library('libpgfeutils',
   fe_utils_sources,
   c_pch: pch_postgres_fe_h,
-  include_directories: [postgres_inc, libpq_inc],
+  include_directories: [libpq_inc, postgres_inc],
   c_args: host_system == 'windows' ? ['-DFD_SETSIZE=1024'] : [],
   dependencies: frontend_common_code,
   kwargs: default_lib_args,
diff --git a/src/interfaces/ecpg/preproc/meson.build b/src/interfaces/ecpg/preproc/meson.build
index aa948efc0dc..c754d885b7b 100644
--- a/src/interfaces/ecpg/preproc/meson.build
+++ b/src/interfaces/ecpg/preproc/meson.build
@@ -78,7 +78,7 @@ endif
 
 ecpg_exe = executable('ecpg',
   ecpg_sources,
-  include_directories: ['.', ecpg_inc, postgres_inc, libpq_inc],
+  include_directories: ['.', ecpg_inc, libpq_inc, postgres_inc],
   c_pch: pch_postgres_fe_h,
   dependencies: [frontend_code],
   kwargs: default_bin_args,
-- 
2.51.1

From aa390e77bedf25c7bf53f8dc5c05b6e826ccbc88 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 14 Jul 2025 11:54:00 +1200
Subject: [PATCH v3 1/2] meson: Fix libpq header include order.

On systems using -Dextra_include_dir that happen to have a copy of libpq
installed there, it's important to put the libpq header search path
ahead of -Dextra_include_dir.  Reorder the dependencies to achieve that.
This matches the order used by configure.

There is probably a better way to do this using declarations rather than
adjusting the order of many lists, but this works for now until someone
shows up with a patch for that.

Back-patch to 16, where meson arrived.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/CA+hUKGKispvxLyrBn3=3mp0BB1N+RBYR5eE2guCOksnwEoOcPQ@mail.gmail.com
---
 contrib/dblink/meson.build                           | 2 +-
 contrib/oid2name/meson.build                         | 2 +-
 contrib/postgres_fdw/meson.build                     | 2 +-
 contrib/vacuumlo/meson.build                         | 2 +-
 src/backend/replication/libpqwalreceiver/meson.build | 2 +-
 src/bin/initdb/meson.build                           | 2 +-
 src/bin/pg_amcheck/meson.build                       | 2 +-
 src/bin/pg_basebackup/meson.build                    | 4 ++--
 src/bin/pg_combinebackup/meson.build                 | 2 +-
 src/bin/pg_ctl/meson.build                           | 2 +-
 src/bin/pg_dump/meson.build                          | 8 ++++----
 src/bin/pg_rewind/meson.build                        | 2 +-
 src/bin/pg_upgrade/meson.build                       | 2 +-
 src/bin/pg_verifybackup/meson.build                  | 2 +-
 src/bin/pgbench/meson.build                          | 2 +-
 src/bin/psql/meson.build                             | 2 +-
 src/bin/scripts/meson.build                          | 8 ++++----
 src/fe_utils/meson.build                             | 2 +-
 src/interfaces/ecpg/ecpglib/meson.build              | 6 +++---
 src/interfaces/ecpg/include/meson.build              | 2 +-
 src/interfaces/ecpg/test/meson.build                 | 4 ++--
 src/interfaces/ecpg/test/thread/meson.build          | 2 +-
 src/interfaces/libpq/test/meson.build                | 4 ++--
 src/test/isolation/meson.build                       | 4 ++--
 src/test/modules/libpq_pipeline/meson.build          | 2 +-
 src/test/modules/oauth_validator/meson.build         | 2 +-
 src/test/modules/test_escape/meson.build             | 2 +-
 src/test/modules/test_int128/meson.build             | 2 +-
 src/test/modules/test_json_parser/meson.build        | 2 +-
 src/test/modules/test_oat_hooks/meson.build          | 4 +++-
 src/test/regress/meson.build                         | 4 ++--
 31 files changed, 46 insertions(+), 44 deletions(-)

diff --git a/contrib/dblink/meson.build b/contrib/dblink/meson.build
index a19ce6cf4b9..28da26d3d45 100644
--- a/contrib/dblink/meson.build
+++ b/contrib/dblink/meson.build
@@ -13,7 +13,7 @@ endif
 dblink = shared_module('dblink',
   dblink_sources,
   kwargs: contrib_mod_args + {
-    'dependencies': contrib_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + contrib_mod_args['dependencies'],
   },
 )
 contrib_targets += dblink
diff --git a/contrib/oid2name/meson.build b/contrib/oid2name/meson.build
index 074f16acd72..dd958f00bdf 100644
--- a/contrib/oid2name/meson.build
+++ b/contrib/oid2name/meson.build
@@ -12,7 +12,7 @@ endif
 
 oid2name = executable('oid2name',
   oid2name_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 contrib_targets += oid2name
diff --git a/contrib/postgres_fdw/meson.build b/contrib/postgres_fdw/meson.build
index aac89ffdde8..a2890251d69 100644
--- a/contrib/postgres_fdw/meson.build
+++ b/contrib/postgres_fdw/meson.build
@@ -17,7 +17,7 @@ endif
 postgres_fdw = shared_module('postgres_fdw',
   postgres_fdw_sources,
   kwargs: contrib_mod_args + {
-    'dependencies': contrib_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + contrib_mod_args['dependencies'],
   },
 )
 contrib_targets += postgres_fdw
diff --git a/contrib/vacuumlo/meson.build b/contrib/vacuumlo/meson.build
index deee1d2832d..51e8fe9a325 100644
--- a/contrib/vacuumlo/meson.build
+++ b/contrib/vacuumlo/meson.build
@@ -12,7 +12,7 @@ endif
 
 vacuumlo = executable('vacuumlo',
   vacuumlo_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 contrib_targets += vacuumlo
diff --git a/src/backend/replication/libpqwalreceiver/meson.build b/src/backend/replication/libpqwalreceiver/meson.build
index 2150f31cfa3..5318a76e29d 100644
--- a/src/backend/replication/libpqwalreceiver/meson.build
+++ b/src/backend/replication/libpqwalreceiver/meson.build
@@ -14,7 +14,7 @@ libpqwalreceiver = shared_module('pqwalreceiver',
   libpqwalreceiver_sources,
   kwargs: pg_mod_args + {
     'name_prefix': 'lib',
-    'dependencies': pg_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + pg_mod_args['dependencies'],
   }
 )
 
diff --git a/src/bin/initdb/meson.build b/src/bin/initdb/meson.build
index 06958e370f3..b8584fe56de 100644
--- a/src/bin/initdb/meson.build
+++ b/src/bin/initdb/meson.build
@@ -21,7 +21,7 @@ initdb = executable('initdb',
   # shared library from a different PG version.  Define
   # USE_PRIVATE_ENCODING_FUNCS to ensure that that happens.
   c_args: ['-DUSE_PRIVATE_ENCODING_FUNCS'],
-  dependencies: [frontend_code, libpq, icu, icu_i18n],
+  dependencies: [libpq, frontend_code, icu, icu_i18n],
   kwargs: default_bin_args,
 )
 bin_targets += initdb
diff --git a/src/bin/pg_amcheck/meson.build b/src/bin/pg_amcheck/meson.build
index 316ea0d40b8..c8f792ff971 100644
--- a/src/bin/pg_amcheck/meson.build
+++ b/src/bin/pg_amcheck/meson.build
@@ -12,7 +12,7 @@ endif
 
 pg_amcheck = executable('pg_amcheck',
   pg_amcheck_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_amcheck
diff --git a/src/bin/pg_basebackup/meson.build b/src/bin/pg_basebackup/meson.build
index 3a7fc10eab0..b85ba465d47 100644
--- a/src/bin/pg_basebackup/meson.build
+++ b/src/bin/pg_basebackup/meson.build
@@ -7,7 +7,7 @@ common_sources = files(
   'walmethods.c',
 )
 
-pg_basebackup_deps = [frontend_code, libpq, lz4, zlib, zstd]
+pg_basebackup_deps = [libpq, frontend_code, lz4, zlib, zstd]
 pg_basebackup_common = static_library('libpg_basebackup_common',
   common_sources,
   dependencies: pg_basebackup_deps,
@@ -45,7 +45,7 @@ endif
 
 pg_createsubscriber = executable('pg_createsubscriber',
   pg_createsubscriber_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_createsubscriber
diff --git a/src/bin/pg_combinebackup/meson.build b/src/bin/pg_combinebackup/meson.build
index e80a4756a7f..04e09162d9b 100644
--- a/src/bin/pg_combinebackup/meson.build
+++ b/src/bin/pg_combinebackup/meson.build
@@ -17,7 +17,7 @@ endif
 
 pg_combinebackup = executable('pg_combinebackup',
   pg_combinebackup_sources,
-  dependencies: [frontend_code],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_combinebackup
diff --git a/src/bin/pg_ctl/meson.build b/src/bin/pg_ctl/meson.build
index e92ba50f8a3..4f4a977dc0f 100644
--- a/src/bin/pg_ctl/meson.build
+++ b/src/bin/pg_ctl/meson.build
@@ -12,7 +12,7 @@ endif
 
 pg_ctl = executable('pg_ctl',
   pg_ctl_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_ctl
diff --git a/src/bin/pg_dump/meson.build b/src/bin/pg_dump/meson.build
index f3c669f484e..2264ed9faa9 100644
--- a/src/bin/pg_dump/meson.build
+++ b/src/bin/pg_dump/meson.build
@@ -22,7 +22,7 @@ pg_dump_common_sources = files(
 pg_dump_common = static_library('libpgdump_common',
   pg_dump_common_sources,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_code, libpq, lz4, zlib, zstd],
+  dependencies: [libpq, frontend_code, lz4, zlib, zstd],
   kwargs: internal_lib_args,
 )
 
@@ -42,7 +42,7 @@ endif
 pg_dump = executable('pg_dump',
   pg_dump_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_dump
@@ -61,7 +61,7 @@ endif
 pg_dumpall = executable('pg_dumpall',
   pg_dumpall_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_dumpall
@@ -80,7 +80,7 @@ endif
 pg_restore = executable('pg_restore',
   pg_restore_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_restore
diff --git a/src/bin/pg_rewind/meson.build b/src/bin/pg_rewind/meson.build
index 97f001d94a5..f241f37673c 100644
--- a/src/bin/pg_rewind/meson.build
+++ b/src/bin/pg_rewind/meson.build
@@ -21,7 +21,7 @@ endif
 
 pg_rewind = executable('pg_rewind',
   pg_rewind_sources,
-  dependencies: [frontend_code, libpq, lz4, zstd],
+  dependencies: [libpq, frontend_code, lz4, zstd],
   c_args: ['-DFRONTEND'], # needed for xlogreader et al
   kwargs: default_bin_args,
 )
diff --git a/src/bin/pg_upgrade/meson.build b/src/bin/pg_upgrade/meson.build
index ac992f0d14b..8aefaeea91f 100644
--- a/src/bin/pg_upgrade/meson.build
+++ b/src/bin/pg_upgrade/meson.build
@@ -28,7 +28,7 @@ endif
 pg_upgrade = executable('pg_upgrade',
   pg_upgrade_sources,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_upgrade
diff --git a/src/bin/pg_verifybackup/meson.build b/src/bin/pg_verifybackup/meson.build
index f45ea790d8e..7aaee24bd79 100644
--- a/src/bin/pg_verifybackup/meson.build
+++ b/src/bin/pg_verifybackup/meson.build
@@ -13,7 +13,7 @@ endif
 
 pg_verifybackup = executable('pg_verifybackup',
   pg_verifybackup_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_verifybackup
diff --git a/src/bin/pgbench/meson.build b/src/bin/pgbench/meson.build
index a2a909a8442..de013cc9827 100644
--- a/src/bin/pgbench/meson.build
+++ b/src/bin/pgbench/meson.build
@@ -27,7 +27,7 @@ endif
 
 pgbench = executable('pgbench',
   pgbench_sources,
-  dependencies: [frontend_code, libpq, thread_dep],
+  dependencies: [libpq, frontend_code, thread_dep],
   include_directories: include_directories('.'),
   c_pch: pch_postgres_fe_h,
   c_args: host_system == 'windows' ? ['-DFD_SETSIZE=1024'] : [],
diff --git a/src/bin/psql/meson.build b/src/bin/psql/meson.build
index d344053c23b..4749d751aa8 100644
--- a/src/bin/psql/meson.build
+++ b/src/bin/psql/meson.build
@@ -58,7 +58,7 @@ psql = executable('psql',
   psql_sources,
   c_pch: pch_postgres_fe_h,
   include_directories: include_directories('.'),
-  dependencies: [frontend_code, libpq, readline],
+  dependencies: [libpq, frontend_code, readline],
   kwargs: default_bin_args,
 )
 bin_targets += psql
diff --git a/src/bin/scripts/meson.build b/src/bin/scripts/meson.build
index a4fed59d1c9..d422ca542f9 100644
--- a/src/bin/scripts/meson.build
+++ b/src/bin/scripts/meson.build
@@ -2,7 +2,7 @@
 
 scripts_common = static_library('libscripts_common',
   files('common.c'),
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: internal_lib_args,
 )
 
@@ -28,7 +28,7 @@ foreach binary : binaries
   binary = executable(binary,
     binary_sources,
     link_with: [scripts_common],
-    dependencies: [frontend_code, libpq],
+    dependencies: [libpq, frontend_code],
     kwargs: default_bin_args,
   )
   bin_targets += binary
@@ -36,7 +36,7 @@ endforeach
 
 vacuuming_common = static_library('libvacuuming_common',
   files('common.c', 'vacuuming.c'),
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: internal_lib_args,
 )
 
@@ -55,7 +55,7 @@ foreach binary : binaries
   binary = executable(binary,
     binary_sources,
     link_with: [vacuuming_common],
-    dependencies: [frontend_code, libpq],
+    dependencies: [libpq, frontend_code],
     kwargs: default_bin_args,
   )
   bin_targets += binary
diff --git a/src/fe_utils/meson.build b/src/fe_utils/meson.build
index ddac3c3a658..0a65b973779 100644
--- a/src/fe_utils/meson.build
+++ b/src/fe_utils/meson.build
@@ -32,7 +32,7 @@ fe_utils_sources += psqlscan
 fe_utils = static_library('libpgfeutils',
   fe_utils_sources,
   c_pch: pch_postgres_fe_h,
-  include_directories: [postgres_inc, libpq_inc],
+  include_directories: [libpq_inc, postgres_inc],
   c_args: host_system == 'windows' ? ['-DFD_SETSIZE=1024'] : [],
   dependencies: frontend_common_code,
   kwargs: default_lib_args,
diff --git a/src/interfaces/ecpg/ecpglib/meson.build b/src/interfaces/ecpg/ecpglib/meson.build
index 8f478c6a73e..fb7d33d2a0e 100644
--- a/src/interfaces/ecpg/ecpglib/meson.build
+++ b/src/interfaces/ecpg/ecpglib/meson.build
@@ -30,7 +30,7 @@ ecpglib_st = static_library('libecpg',
   include_directories: ecpglib_inc,
   c_args: ecpglib_c_args,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_stlib_code, thread_dep, libpq],
+  dependencies: [libpq, frontend_stlib_code, thread_dep],
   link_with: [ecpg_pgtypes_st],
   kwargs: default_lib_args,
 )
@@ -41,7 +41,7 @@ ecpglib_so = shared_library('libecpg',
   include_directories: ecpglib_inc,
   c_args: ecpglib_c_args,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_shlib_code, libpq, thread_dep],
+  dependencies: [libpq, frontend_shlib_code, thread_dep],
   link_with: ecpg_pgtypes_so,
   soversion: host_system != 'windows' ? '6' : '',
   darwin_versions: ['6', '6.' + pg_version_major.to_string()],
@@ -58,7 +58,7 @@ pkgconfig.generate(
   url: pg_url,
   libraries: ecpglib_so,
   libraries_private: [frontend_stlib_code, thread_dep],
-  requires_private: ['libpgtypes', 'libpq'],
+  requires_private: ['libpq', 'libpgtypes'],
 )
 
 subdir('po', if_found: libintl)
diff --git a/src/interfaces/ecpg/include/meson.build b/src/interfaces/ecpg/include/meson.build
index a6541e1a686..133ebe2f11f 100644
--- a/src/interfaces/ecpg/include/meson.build
+++ b/src/interfaces/ecpg/include/meson.build
@@ -1,6 +1,6 @@
 # Copyright (c) 2022-2025, PostgreSQL Global Development Group
 
-ecpg_inc = include_directories('.')
+ecpg_inc = [libpq_inc, include_directories('.')]
 
 ecpg_conf_keys = [
   'SIZEOF_LONG',
diff --git a/src/interfaces/ecpg/test/meson.build b/src/interfaces/ecpg/test/meson.build
index 4ccdf9d295a..0d48e035e5a 100644
--- a/src/interfaces/ecpg/test/meson.build
+++ b/src/interfaces/ecpg/test/meson.build
@@ -20,7 +20,7 @@ pg_regress_ecpg = executable('pg_regress_ecpg',
   pg_regress_ecpg_sources,
   c_args: pg_regress_cflags,
   include_directories: [pg_regress_inc, include_directories('.')],
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false
   },
@@ -30,7 +30,7 @@ ecpg_test_dependencies += pg_regress_ecpg
 # create .c files and executables from .pgc files
 ecpg_test_exec_kw = {
   'c_args': cflags_no_missing_var_decls,
-  'dependencies': [frontend_code, libpq],
+  'dependencies': [libpq, frontend_code],
   'include_directories': [ecpg_inc],
   'link_with': [ecpglib_so, ecpg_compat_so, ecpg_pgtypes_so],
   'build_by_default': false,
diff --git a/src/interfaces/ecpg/test/thread/meson.build b/src/interfaces/ecpg/test/thread/meson.build
index 6a6745ce0fc..2c34a611898 100644
--- a/src/interfaces/ecpg/test/thread/meson.build
+++ b/src/interfaces/ecpg/test/thread/meson.build
@@ -18,6 +18,6 @@ foreach pgc_file : pgc_files
 
   ecpg_test_dependencies += executable(pgc_file,
     exe_input,
-    kwargs: ecpg_test_exec_kw + {'dependencies': [frontend_code, libpq, thread_dep,]},
+    kwargs: ecpg_test_exec_kw + {'dependencies': [libpq, frontend_code, thread_dep,]},
   )
 endforeach
diff --git a/src/interfaces/libpq/test/meson.build b/src/interfaces/libpq/test/meson.build
index 07a5facc321..75d2012ba17 100644
--- a/src/interfaces/libpq/test/meson.build
+++ b/src/interfaces/libpq/test/meson.build
@@ -14,7 +14,7 @@ endif
 
 libpq_test_deps += executable('libpq_uri_regress',
   libpq_uri_regress_sources,
-  dependencies: [frontend_no_fe_utils_code, libpq],
+  dependencies: [libpq, frontend_no_fe_utils_code],
   kwargs: default_bin_args + {
     'install': false,
   }
@@ -33,7 +33,7 @@ endif
 
 libpq_test_deps += executable('libpq_testclient',
   libpq_testclient_sources,
-  dependencies: [frontend_no_fe_utils_code, libpq],
+  dependencies: [libpq, frontend_no_fe_utils_code],
   kwargs: default_bin_args + {
     'install': false,
   }
diff --git a/src/test/isolation/meson.build b/src/test/isolation/meson.build
index a180e4e2741..660b11eff8b 100644
--- a/src/test/isolation/meson.build
+++ b/src/test/isolation/meson.build
@@ -35,7 +35,7 @@ pg_isolation_regress = executable('pg_isolation_regress',
   isolation_sources,
   c_args: pg_regress_cflags,
   include_directories: pg_regress_inc,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/isolation',
   },
@@ -52,7 +52,7 @@ endif
 isolationtester = executable('isolationtester',
   isolationtester_sources,
   include_directories: include_directories('.'),
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/isolation',
   },
diff --git a/src/test/modules/libpq_pipeline/meson.build b/src/test/modules/libpq_pipeline/meson.build
index 3fd70a04a38..83201111ca3 100644
--- a/src/test/modules/libpq_pipeline/meson.build
+++ b/src/test/modules/libpq_pipeline/meson.build
@@ -12,7 +12,7 @@ endif
 
 libpq_pipeline = executable('libpq_pipeline',
   libpq_pipeline_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   },
diff --git a/src/test/modules/oauth_validator/meson.build b/src/test/modules/oauth_validator/meson.build
index a6f937fd7d7..2cd5c4cd537 100644
--- a/src/test/modules/oauth_validator/meson.build
+++ b/src/test/modules/oauth_validator/meson.build
@@ -60,7 +60,7 @@ endif
 
 oauth_hook_client = executable('oauth_hook_client',
   oauth_hook_client_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   },
diff --git a/src/test/modules/test_escape/meson.build b/src/test/modules/test_escape/meson.build
index a21341d5067..04fd0be0889 100644
--- a/src/test/modules/test_escape/meson.build
+++ b/src/test/modules/test_escape/meson.build
@@ -10,7 +10,7 @@ endif
 
 test_escape = executable('test_escape',
   test_escape_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   }
diff --git a/src/test/modules/test_int128/meson.build b/src/test/modules/test_int128/meson.build
index 4c2be7a0326..94bca2edc5c 100644
--- a/src/test/modules/test_int128/meson.build
+++ b/src/test/modules/test_int128/meson.build
@@ -12,7 +12,7 @@ endif
 
 test_int128 = executable('test_int128',
   test_int128_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   },
diff --git a/src/test/modules/test_json_parser/meson.build b/src/test/modules/test_json_parser/meson.build
index 5672045f496..2c6031a14df 100644
--- a/src/test/modules/test_json_parser/meson.build
+++ b/src/test/modules/test_json_parser/meson.build
@@ -23,7 +23,7 @@ test_json_parser_incremental = executable('test_json_parser_incremental',
 # the shared-library flavor of jsonapi.
 test_json_parser_incremental_shlib = executable('test_json_parser_incremental_shlib',
   test_json_parser_incremental_sources,
-  dependencies: [frontend_shlib_code, libpq],
+  dependencies: [libpq, frontend_shlib_code],
   c_args: ['-DJSONAPI_SHLIB_ALLOC'],
   link_with: [common_excluded_shlib],
   kwargs: default_bin_args + {
diff --git a/src/test/modules/test_oat_hooks/meson.build b/src/test/modules/test_oat_hooks/meson.build
index 1e600b0f4c7..6f0c4afd433 100644
--- a/src/test/modules/test_oat_hooks/meson.build
+++ b/src/test/modules/test_oat_hooks/meson.build
@@ -12,7 +12,9 @@ endif
 
 test_oat_hooks = shared_module('test_oat_hooks',
   test_oat_hooks_sources,
-  kwargs: pg_test_mod_args,
+  kwargs: pg_test_mod_args + {
+	'dependencies': [libpq] + pg_test_mod_args['dependencies'],
+  }
 )
 test_install_libs += test_oat_hooks
 
diff --git a/src/test/regress/meson.build b/src/test/regress/meson.build
index 1da9e9462a9..99f402f49a8 100644
--- a/src/test/regress/meson.build
+++ b/src/test/regress/meson.build
@@ -2,7 +2,7 @@
 
 # also used by isolationtester and ecpg tests
 pg_regress_c = files('pg_regress.c')
-pg_regress_inc = include_directories('.')
+pg_regress_inc = [libpq_inc, include_directories('.')]
 
 regress_sources = pg_regress_c + files(
   'pg_regress_main.c'
@@ -30,7 +30,7 @@ endif
 pg_regress = executable('pg_regress',
   regress_sources,
   c_args: pg_regress_cflags,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/regress',
   },
-- 
2.51.1

From 23df76b10985b3624a71e9357b98a6cccf377542 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 3 Nov 2025 11:32:57 +1300
Subject: [PATCH v3 2/2] ci: Test include path order with decoy libpq-fe.h.

If the configure or meson scripts would allow headers from a copy of
libpq installed under --with-includes or -Dextra_include_dirs to be
found before the in-tree copy we need, then this canary header will
raise an error.

This problem has bitten us in both build systems, but often goes
unnoticed until libpq-fe.h changes incompatibly and someone with an
affected system notices.  This test would cause CI to fail fast.

Also add missing set -e to the shell scripts run under su, since
otherwise the build step would confusingly succeed.

Discussion: https://postgr.es/m/CA%2BhUKG%2Bx-cys30%3D7L2B8%3DcZ%2B-z6QDOj-oQy9O3CnkeXnrnm3OQ%40mail.gmail.com
---
 .cirrus.tasks.yml | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/.cirrus.tasks.yml b/.cirrus.tasks.yml
index f2581cfb2e5..3df6de6acd9 100644
--- a/.cirrus.tasks.yml
+++ b/.cirrus.tasks.yml
@@ -424,6 +424,8 @@ task:
     CCACHE_DIR: /tmp/ccache_dir
     DEBUGINFOD_URLS: "https://debuginfod.debian.net"
 
+    POISONED_HEADERS: /tmp/poisoned_headers
+
     # Enable a reasonable set of sanitizers. Use the linux task for that, as
     # it's one of the fastest tasks (without sanitizers). Also several of the
     # sanitizers work best on linux.
@@ -492,11 +494,24 @@ task:
     #apt-get update
     #DEBIAN_FRONTEND=noninteractive apt-get -y install ...
 
+  # Detect mistakes that would allow unwanted headers from outside our tree be
+  # found with --with-includes or -Dextra_include_dirs.  That is primarily a
+  # risk on non-Linux systems that install packages under eg /usr/local that
+  # must be explicitly added to the header search path, but this is a
+  # convenient place to test both build systems.
+  setup_poisoned_headers_script: |
+    for header in "libpq-fe.h" "libpq/libpq-fe.h" ; do
+      mkdir -p "${POISONED_HEADERS}/$(dirname $header)"
+      echo '#error "external header hides in-tree header"' \
+      > "${POISONED_HEADERS}/$header"
+    done
+
   matrix:
     # SPECIAL:
     # - Uses address sanitizer, sanitizer failures are typically printed in
     #   the server log
     # - Configures postgres with a small segment size
+    # - Poisoned headers in search path
     - name: Linux - Debian Bookworm - Autoconf
 
       env:
@@ -517,6 +532,7 @@ task:
             --with-segsize-blocks=6 \
             --with-libnuma \
             --with-liburing \
+            --with-includes="${POISONED_HEADERS}" \
             \
             ${LINUX_CONFIGURE_FEATURES} \
             \
@@ -540,6 +556,7 @@ task:
     # - Test both 64bit and 32 bit builds
     # - uses io_method=io_uring
     # - Uses meson feature autodetection
+    # - Poisoned headers in search path
     - name: Linux - Debian Bookworm - Meson
 
       env:
@@ -552,6 +569,7 @@ task:
         su postgres <<-EOF
           meson setup \
             ${MESON_COMMON_PG_CONFIG_ARGS} \
+            -Dextra_include_dirs="${POISONED_HEADERS}" \
             --buildtype=debug \
             ${LINUX_MESON_FEATURES} -Dllvm=enabled \
             build
@@ -564,6 +582,7 @@ task:
           export CC='ccache gcc -m32'
           meson setup \
             ${MESON_COMMON_PG_CONFIG_ARGS} \
+            -Dextra_include_dirs="${POISONED_HEADERS}" \
             --buildtype=debug \
             --pkg-config-path /usr/lib/i386-linux-gnu/pkgconfig/ \
             -DPERL=perl5.36-i386-linux-gnu \
@@ -573,12 +592,14 @@ task:
 
       build_script: |
         su postgres <<-EOF
+          set -e
           ninja -C build -j${BUILD_JOBS} ${MBUILD_TARGET}
           ninja -C build -t missingdeps
         EOF
 
       build_32_script: |
         su postgres <<-EOF
+          set -e
           ninja -C build-32 -j${BUILD_JOBS} ${MBUILD_TARGET}
           ninja -C build -t missingdeps
         EOF
-- 
2.51.1

From 172ebde3ea93a9c9bd3db8a134cd873ca3daedda Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 14 Jul 2025 11:54:00 +1200
Subject: [PATCH v4 1/4] meson: Fix libpq header include order.

Don't allow external copies of libpq-fe.h to hide the in-tree libpq's
headers.  libpq is now always declared as the first dependency, so that
it can arrange for libpq_inc to be searched before extra_include_dirs,
c_flags or system/ports include directory discovered by Meson.

This is mostly a mechanical change to multiple dependency lists.  A
separate commit will add a CI check to prevent future mistakes.

This clearly didn't affect many people, maybe just me (Thomas), but it
could have broken on basically any non-Linux system that happened to
install a libpq-with-headers package.

Back-patch to 16, where meson arrived.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Tristan Partin <tristan@partin.io>
Discussion: https://postgr.es/m/CA+hUKGKispvxLyrBn3=3mp0BB1N+RBYR5eE2guCOksnwEoOcPQ@mail.gmail.com
---
 contrib/dblink/meson.build                           | 2 +-
 contrib/oid2name/meson.build                         | 2 +-
 contrib/postgres_fdw/meson.build                     | 2 +-
 contrib/vacuumlo/meson.build                         | 2 +-
 src/backend/replication/libpqwalreceiver/meson.build | 2 +-
 src/bin/initdb/meson.build                           | 2 +-
 src/bin/pg_amcheck/meson.build                       | 2 +-
 src/bin/pg_basebackup/meson.build                    | 4 ++--
 src/bin/pg_ctl/meson.build                           | 2 +-
 src/bin/pg_dump/meson.build                          | 8 ++++----
 src/bin/pg_rewind/meson.build                        | 2 +-
 src/bin/pg_upgrade/meson.build                       | 2 +-
 src/bin/pg_verifybackup/meson.build                  | 2 +-
 src/bin/pgbench/meson.build                          | 2 +-
 src/bin/psql/meson.build                             | 2 +-
 src/bin/scripts/meson.build                          | 8 ++++----
 src/fe_utils/meson.build                             | 2 +-
 src/interfaces/ecpg/ecpglib/meson.build              | 6 +++---
 src/interfaces/ecpg/include/meson.build              | 2 +-
 src/interfaces/ecpg/test/meson.build                 | 4 ++--
 src/interfaces/ecpg/test/thread/meson.build          | 2 +-
 src/interfaces/libpq/test/meson.build                | 4 ++--
 src/test/isolation/meson.build                       | 4 ++--
 src/test/modules/libpq_pipeline/meson.build          | 2 +-
 src/test/modules/oauth_validator/meson.build         | 2 +-
 src/test/modules/test_escape/meson.build             | 2 +-
 src/test/modules/test_int128/meson.build             | 2 +-
 src/test/modules/test_json_parser/meson.build        | 2 +-
 src/test/regress/meson.build                         | 2 +-
 29 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/contrib/dblink/meson.build b/contrib/dblink/meson.build
index a19ce6cf4b9..28da26d3d45 100644
--- a/contrib/dblink/meson.build
+++ b/contrib/dblink/meson.build
@@ -13,7 +13,7 @@ endif
 dblink = shared_module('dblink',
   dblink_sources,
   kwargs: contrib_mod_args + {
-    'dependencies': contrib_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + contrib_mod_args['dependencies'],
   },
 )
 contrib_targets += dblink
diff --git a/contrib/oid2name/meson.build b/contrib/oid2name/meson.build
index 074f16acd72..dd958f00bdf 100644
--- a/contrib/oid2name/meson.build
+++ b/contrib/oid2name/meson.build
@@ -12,7 +12,7 @@ endif
 
 oid2name = executable('oid2name',
   oid2name_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 contrib_targets += oid2name
diff --git a/contrib/postgres_fdw/meson.build b/contrib/postgres_fdw/meson.build
index aac89ffdde8..a2890251d69 100644
--- a/contrib/postgres_fdw/meson.build
+++ b/contrib/postgres_fdw/meson.build
@@ -17,7 +17,7 @@ endif
 postgres_fdw = shared_module('postgres_fdw',
   postgres_fdw_sources,
   kwargs: contrib_mod_args + {
-    'dependencies': contrib_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + contrib_mod_args['dependencies'],
   },
 )
 contrib_targets += postgres_fdw
diff --git a/contrib/vacuumlo/meson.build b/contrib/vacuumlo/meson.build
index deee1d2832d..51e8fe9a325 100644
--- a/contrib/vacuumlo/meson.build
+++ b/contrib/vacuumlo/meson.build
@@ -12,7 +12,7 @@ endif
 
 vacuumlo = executable('vacuumlo',
   vacuumlo_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 contrib_targets += vacuumlo
diff --git a/src/backend/replication/libpqwalreceiver/meson.build b/src/backend/replication/libpqwalreceiver/meson.build
index 2150f31cfa3..5318a76e29d 100644
--- a/src/backend/replication/libpqwalreceiver/meson.build
+++ b/src/backend/replication/libpqwalreceiver/meson.build
@@ -14,7 +14,7 @@ libpqwalreceiver = shared_module('pqwalreceiver',
   libpqwalreceiver_sources,
   kwargs: pg_mod_args + {
     'name_prefix': 'lib',
-    'dependencies': pg_mod_args['dependencies'] + [libpq],
+    'dependencies': [libpq] + pg_mod_args['dependencies'],
   }
 )
 
diff --git a/src/bin/initdb/meson.build b/src/bin/initdb/meson.build
index 06958e370f3..b8584fe56de 100644
--- a/src/bin/initdb/meson.build
+++ b/src/bin/initdb/meson.build
@@ -21,7 +21,7 @@ initdb = executable('initdb',
   # shared library from a different PG version.  Define
   # USE_PRIVATE_ENCODING_FUNCS to ensure that that happens.
   c_args: ['-DUSE_PRIVATE_ENCODING_FUNCS'],
-  dependencies: [frontend_code, libpq, icu, icu_i18n],
+  dependencies: [libpq, frontend_code, icu, icu_i18n],
   kwargs: default_bin_args,
 )
 bin_targets += initdb
diff --git a/src/bin/pg_amcheck/meson.build b/src/bin/pg_amcheck/meson.build
index 316ea0d40b8..c8f792ff971 100644
--- a/src/bin/pg_amcheck/meson.build
+++ b/src/bin/pg_amcheck/meson.build
@@ -12,7 +12,7 @@ endif
 
 pg_amcheck = executable('pg_amcheck',
   pg_amcheck_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_amcheck
diff --git a/src/bin/pg_basebackup/meson.build b/src/bin/pg_basebackup/meson.build
index 3a7fc10eab0..b85ba465d47 100644
--- a/src/bin/pg_basebackup/meson.build
+++ b/src/bin/pg_basebackup/meson.build
@@ -7,7 +7,7 @@ common_sources = files(
   'walmethods.c',
 )
 
-pg_basebackup_deps = [frontend_code, libpq, lz4, zlib, zstd]
+pg_basebackup_deps = [libpq, frontend_code, lz4, zlib, zstd]
 pg_basebackup_common = static_library('libpg_basebackup_common',
   common_sources,
   dependencies: pg_basebackup_deps,
@@ -45,7 +45,7 @@ endif
 
 pg_createsubscriber = executable('pg_createsubscriber',
   pg_createsubscriber_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_createsubscriber
diff --git a/src/bin/pg_ctl/meson.build b/src/bin/pg_ctl/meson.build
index e92ba50f8a3..4f4a977dc0f 100644
--- a/src/bin/pg_ctl/meson.build
+++ b/src/bin/pg_ctl/meson.build
@@ -12,7 +12,7 @@ endif
 
 pg_ctl = executable('pg_ctl',
   pg_ctl_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_ctl
diff --git a/src/bin/pg_dump/meson.build b/src/bin/pg_dump/meson.build
index f3c669f484e..2264ed9faa9 100644
--- a/src/bin/pg_dump/meson.build
+++ b/src/bin/pg_dump/meson.build
@@ -22,7 +22,7 @@ pg_dump_common_sources = files(
 pg_dump_common = static_library('libpgdump_common',
   pg_dump_common_sources,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_code, libpq, lz4, zlib, zstd],
+  dependencies: [libpq, frontend_code, lz4, zlib, zstd],
   kwargs: internal_lib_args,
 )
 
@@ -42,7 +42,7 @@ endif
 pg_dump = executable('pg_dump',
   pg_dump_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_dump
@@ -61,7 +61,7 @@ endif
 pg_dumpall = executable('pg_dumpall',
   pg_dumpall_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_dumpall
@@ -80,7 +80,7 @@ endif
 pg_restore = executable('pg_restore',
   pg_restore_sources,
   link_with: [pg_dump_common],
-  dependencies: [frontend_code, libpq, zlib],
+  dependencies: [libpq, frontend_code, zlib],
   kwargs: default_bin_args,
 )
 bin_targets += pg_restore
diff --git a/src/bin/pg_rewind/meson.build b/src/bin/pg_rewind/meson.build
index 97f001d94a5..f241f37673c 100644
--- a/src/bin/pg_rewind/meson.build
+++ b/src/bin/pg_rewind/meson.build
@@ -21,7 +21,7 @@ endif
 
 pg_rewind = executable('pg_rewind',
   pg_rewind_sources,
-  dependencies: [frontend_code, libpq, lz4, zstd],
+  dependencies: [libpq, frontend_code, lz4, zstd],
   c_args: ['-DFRONTEND'], # needed for xlogreader et al
   kwargs: default_bin_args,
 )
diff --git a/src/bin/pg_upgrade/meson.build b/src/bin/pg_upgrade/meson.build
index ac992f0d14b..8aefaeea91f 100644
--- a/src/bin/pg_upgrade/meson.build
+++ b/src/bin/pg_upgrade/meson.build
@@ -28,7 +28,7 @@ endif
 pg_upgrade = executable('pg_upgrade',
   pg_upgrade_sources,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_upgrade
diff --git a/src/bin/pg_verifybackup/meson.build b/src/bin/pg_verifybackup/meson.build
index f45ea790d8e..7aaee24bd79 100644
--- a/src/bin/pg_verifybackup/meson.build
+++ b/src/bin/pg_verifybackup/meson.build
@@ -13,7 +13,7 @@ endif
 
 pg_verifybackup = executable('pg_verifybackup',
   pg_verifybackup_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args,
 )
 bin_targets += pg_verifybackup
diff --git a/src/bin/pgbench/meson.build b/src/bin/pgbench/meson.build
index a2a909a8442..de013cc9827 100644
--- a/src/bin/pgbench/meson.build
+++ b/src/bin/pgbench/meson.build
@@ -27,7 +27,7 @@ endif
 
 pgbench = executable('pgbench',
   pgbench_sources,
-  dependencies: [frontend_code, libpq, thread_dep],
+  dependencies: [libpq, frontend_code, thread_dep],
   include_directories: include_directories('.'),
   c_pch: pch_postgres_fe_h,
   c_args: host_system == 'windows' ? ['-DFD_SETSIZE=1024'] : [],
diff --git a/src/bin/psql/meson.build b/src/bin/psql/meson.build
index d344053c23b..4749d751aa8 100644
--- a/src/bin/psql/meson.build
+++ b/src/bin/psql/meson.build
@@ -58,7 +58,7 @@ psql = executable('psql',
   psql_sources,
   c_pch: pch_postgres_fe_h,
   include_directories: include_directories('.'),
-  dependencies: [frontend_code, libpq, readline],
+  dependencies: [libpq, frontend_code, readline],
   kwargs: default_bin_args,
 )
 bin_targets += psql
diff --git a/src/bin/scripts/meson.build b/src/bin/scripts/meson.build
index a4fed59d1c9..d422ca542f9 100644
--- a/src/bin/scripts/meson.build
+++ b/src/bin/scripts/meson.build
@@ -2,7 +2,7 @@
 
 scripts_common = static_library('libscripts_common',
   files('common.c'),
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: internal_lib_args,
 )
 
@@ -28,7 +28,7 @@ foreach binary : binaries
   binary = executable(binary,
     binary_sources,
     link_with: [scripts_common],
-    dependencies: [frontend_code, libpq],
+    dependencies: [libpq, frontend_code],
     kwargs: default_bin_args,
   )
   bin_targets += binary
@@ -36,7 +36,7 @@ endforeach
 
 vacuuming_common = static_library('libvacuuming_common',
   files('common.c', 'vacuuming.c'),
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: internal_lib_args,
 )
 
@@ -55,7 +55,7 @@ foreach binary : binaries
   binary = executable(binary,
     binary_sources,
     link_with: [vacuuming_common],
-    dependencies: [frontend_code, libpq],
+    dependencies: [libpq, frontend_code],
     kwargs: default_bin_args,
   )
   bin_targets += binary
diff --git a/src/fe_utils/meson.build b/src/fe_utils/meson.build
index ddac3c3a658..0a65b973779 100644
--- a/src/fe_utils/meson.build
+++ b/src/fe_utils/meson.build
@@ -32,7 +32,7 @@ fe_utils_sources += psqlscan
 fe_utils = static_library('libpgfeutils',
   fe_utils_sources,
   c_pch: pch_postgres_fe_h,
-  include_directories: [postgres_inc, libpq_inc],
+  include_directories: [libpq_inc, postgres_inc],
   c_args: host_system == 'windows' ? ['-DFD_SETSIZE=1024'] : [],
   dependencies: frontend_common_code,
   kwargs: default_lib_args,
diff --git a/src/interfaces/ecpg/ecpglib/meson.build b/src/interfaces/ecpg/ecpglib/meson.build
index 8f478c6a73e..fb7d33d2a0e 100644
--- a/src/interfaces/ecpg/ecpglib/meson.build
+++ b/src/interfaces/ecpg/ecpglib/meson.build
@@ -30,7 +30,7 @@ ecpglib_st = static_library('libecpg',
   include_directories: ecpglib_inc,
   c_args: ecpglib_c_args,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_stlib_code, thread_dep, libpq],
+  dependencies: [libpq, frontend_stlib_code, thread_dep],
   link_with: [ecpg_pgtypes_st],
   kwargs: default_lib_args,
 )
@@ -41,7 +41,7 @@ ecpglib_so = shared_library('libecpg',
   include_directories: ecpglib_inc,
   c_args: ecpglib_c_args,
   c_pch: pch_postgres_fe_h,
-  dependencies: [frontend_shlib_code, libpq, thread_dep],
+  dependencies: [libpq, frontend_shlib_code, thread_dep],
   link_with: ecpg_pgtypes_so,
   soversion: host_system != 'windows' ? '6' : '',
   darwin_versions: ['6', '6.' + pg_version_major.to_string()],
@@ -58,7 +58,7 @@ pkgconfig.generate(
   url: pg_url,
   libraries: ecpglib_so,
   libraries_private: [frontend_stlib_code, thread_dep],
-  requires_private: ['libpgtypes', 'libpq'],
+  requires_private: ['libpq', 'libpgtypes'],
 )
 
 subdir('po', if_found: libintl)
diff --git a/src/interfaces/ecpg/include/meson.build b/src/interfaces/ecpg/include/meson.build
index a6541e1a686..133ebe2f11f 100644
--- a/src/interfaces/ecpg/include/meson.build
+++ b/src/interfaces/ecpg/include/meson.build
@@ -1,6 +1,6 @@
 # Copyright (c) 2022-2025, PostgreSQL Global Development Group
 
-ecpg_inc = include_directories('.')
+ecpg_inc = [libpq_inc, include_directories('.')]
 
 ecpg_conf_keys = [
   'SIZEOF_LONG',
diff --git a/src/interfaces/ecpg/test/meson.build b/src/interfaces/ecpg/test/meson.build
index 4ccdf9d295a..0d48e035e5a 100644
--- a/src/interfaces/ecpg/test/meson.build
+++ b/src/interfaces/ecpg/test/meson.build
@@ -20,7 +20,7 @@ pg_regress_ecpg = executable('pg_regress_ecpg',
   pg_regress_ecpg_sources,
   c_args: pg_regress_cflags,
   include_directories: [pg_regress_inc, include_directories('.')],
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false
   },
@@ -30,7 +30,7 @@ ecpg_test_dependencies += pg_regress_ecpg
 # create .c files and executables from .pgc files
 ecpg_test_exec_kw = {
   'c_args': cflags_no_missing_var_decls,
-  'dependencies': [frontend_code, libpq],
+  'dependencies': [libpq, frontend_code],
   'include_directories': [ecpg_inc],
   'link_with': [ecpglib_so, ecpg_compat_so, ecpg_pgtypes_so],
   'build_by_default': false,
diff --git a/src/interfaces/ecpg/test/thread/meson.build b/src/interfaces/ecpg/test/thread/meson.build
index 6a6745ce0fc..2c34a611898 100644
--- a/src/interfaces/ecpg/test/thread/meson.build
+++ b/src/interfaces/ecpg/test/thread/meson.build
@@ -18,6 +18,6 @@ foreach pgc_file : pgc_files
 
   ecpg_test_dependencies += executable(pgc_file,
     exe_input,
-    kwargs: ecpg_test_exec_kw + {'dependencies': [frontend_code, libpq, thread_dep,]},
+    kwargs: ecpg_test_exec_kw + {'dependencies': [libpq, frontend_code, thread_dep,]},
   )
 endforeach
diff --git a/src/interfaces/libpq/test/meson.build b/src/interfaces/libpq/test/meson.build
index 07a5facc321..75d2012ba17 100644
--- a/src/interfaces/libpq/test/meson.build
+++ b/src/interfaces/libpq/test/meson.build
@@ -14,7 +14,7 @@ endif
 
 libpq_test_deps += executable('libpq_uri_regress',
   libpq_uri_regress_sources,
-  dependencies: [frontend_no_fe_utils_code, libpq],
+  dependencies: [libpq, frontend_no_fe_utils_code],
   kwargs: default_bin_args + {
     'install': false,
   }
@@ -33,7 +33,7 @@ endif
 
 libpq_test_deps += executable('libpq_testclient',
   libpq_testclient_sources,
-  dependencies: [frontend_no_fe_utils_code, libpq],
+  dependencies: [libpq, frontend_no_fe_utils_code],
   kwargs: default_bin_args + {
     'install': false,
   }
diff --git a/src/test/isolation/meson.build b/src/test/isolation/meson.build
index a180e4e2741..660b11eff8b 100644
--- a/src/test/isolation/meson.build
+++ b/src/test/isolation/meson.build
@@ -35,7 +35,7 @@ pg_isolation_regress = executable('pg_isolation_regress',
   isolation_sources,
   c_args: pg_regress_cflags,
   include_directories: pg_regress_inc,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/isolation',
   },
@@ -52,7 +52,7 @@ endif
 isolationtester = executable('isolationtester',
   isolationtester_sources,
   include_directories: include_directories('.'),
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/isolation',
   },
diff --git a/src/test/modules/libpq_pipeline/meson.build b/src/test/modules/libpq_pipeline/meson.build
index 3fd70a04a38..83201111ca3 100644
--- a/src/test/modules/libpq_pipeline/meson.build
+++ b/src/test/modules/libpq_pipeline/meson.build
@@ -12,7 +12,7 @@ endif
 
 libpq_pipeline = executable('libpq_pipeline',
   libpq_pipeline_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   },
diff --git a/src/test/modules/oauth_validator/meson.build b/src/test/modules/oauth_validator/meson.build
index a6f937fd7d7..2cd5c4cd537 100644
--- a/src/test/modules/oauth_validator/meson.build
+++ b/src/test/modules/oauth_validator/meson.build
@@ -60,7 +60,7 @@ endif
 
 oauth_hook_client = executable('oauth_hook_client',
   oauth_hook_client_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   },
diff --git a/src/test/modules/test_escape/meson.build b/src/test/modules/test_escape/meson.build
index a21341d5067..04fd0be0889 100644
--- a/src/test/modules/test_escape/meson.build
+++ b/src/test/modules/test_escape/meson.build
@@ -10,7 +10,7 @@ endif
 
 test_escape = executable('test_escape',
   test_escape_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   }
diff --git a/src/test/modules/test_int128/meson.build b/src/test/modules/test_int128/meson.build
index 4c2be7a0326..94bca2edc5c 100644
--- a/src/test/modules/test_int128/meson.build
+++ b/src/test/modules/test_int128/meson.build
@@ -12,7 +12,7 @@ endif
 
 test_int128 = executable('test_int128',
   test_int128_sources,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install': false,
   },
diff --git a/src/test/modules/test_json_parser/meson.build b/src/test/modules/test_json_parser/meson.build
index 5672045f496..2c6031a14df 100644
--- a/src/test/modules/test_json_parser/meson.build
+++ b/src/test/modules/test_json_parser/meson.build
@@ -23,7 +23,7 @@ test_json_parser_incremental = executable('test_json_parser_incremental',
 # the shared-library flavor of jsonapi.
 test_json_parser_incremental_shlib = executable('test_json_parser_incremental_shlib',
   test_json_parser_incremental_sources,
-  dependencies: [frontend_shlib_code, libpq],
+  dependencies: [libpq, frontend_shlib_code],
   c_args: ['-DJSONAPI_SHLIB_ALLOC'],
   link_with: [common_excluded_shlib],
   kwargs: default_bin_args + {
diff --git a/src/test/regress/meson.build b/src/test/regress/meson.build
index 1da9e9462a9..3fe900d5847 100644
--- a/src/test/regress/meson.build
+++ b/src/test/regress/meson.build
@@ -30,7 +30,7 @@ endif
 pg_regress = executable('pg_regress',
   regress_sources,
   c_args: pg_regress_cflags,
-  dependencies: [frontend_code, libpq],
+  dependencies: [libpq, frontend_code],
   kwargs: default_bin_args + {
     'install_dir': dir_pgxs / 'src/test/regress',
   },
-- 
2.51.1

From 3ed517c7904666e1f9dcf45171ffa2684126eb2f Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Mon, 3 Nov 2025 11:32:57 +1300
Subject: [PATCH v4 2/4] ci: Test include path order with canary libpq-fe.h.

If the build script would allow libpq-fe.h installed under
--with-includes (configure) or -Dextra_include_dirs (meson) to hide the
in-tree header, it will now reach an #error in contrived error on CI.
This tests that libpq is ordered correctly for all code that includes
the header.  The list of canary headers could be extended in future.

Also add missing set -e to the shell scripts run under su, since
otherwise the build step would confusingly succeed despite not
completing.

Reviewed-by: Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKG%2Bx-cys30%3D7L2B8%3DcZ%2B-z6QDOj-oQy9O3CnkeXnrnm3OQ%40mail.gmail.com
---
 .cirrus.tasks.yml | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/.cirrus.tasks.yml b/.cirrus.tasks.yml
index f2581cfb2e5..3df6de6acd9 100644
--- a/.cirrus.tasks.yml
+++ b/.cirrus.tasks.yml
@@ -424,6 +424,8 @@ task:
     CCACHE_DIR: /tmp/ccache_dir
     DEBUGINFOD_URLS: "https://debuginfod.debian.net"
 
+    POISONED_HEADERS: /tmp/poisoned_headers
+
     # Enable a reasonable set of sanitizers. Use the linux task for that, as
     # it's one of the fastest tasks (without sanitizers). Also several of the
     # sanitizers work best on linux.
@@ -492,11 +494,24 @@ task:
     #apt-get update
     #DEBIAN_FRONTEND=noninteractive apt-get -y install ...
 
+  # Detect mistakes that would allow unwanted headers from outside our tree be
+  # found with --with-includes or -Dextra_include_dirs.  That is primarily a
+  # risk on non-Linux systems that install packages under eg /usr/local that
+  # must be explicitly added to the header search path, but this is a
+  # convenient place to test both build systems.
+  setup_poisoned_headers_script: |
+    for header in "libpq-fe.h" "libpq/libpq-fe.h" ; do
+      mkdir -p "${POISONED_HEADERS}/$(dirname $header)"
+      echo '#error "external header hides in-tree header"' \
+      > "${POISONED_HEADERS}/$header"
+    done
+
   matrix:
     # SPECIAL:
     # - Uses address sanitizer, sanitizer failures are typically printed in
     #   the server log
     # - Configures postgres with a small segment size
+    # - Poisoned headers in search path
     - name: Linux - Debian Bookworm - Autoconf
 
       env:
@@ -517,6 +532,7 @@ task:
             --with-segsize-blocks=6 \
             --with-libnuma \
             --with-liburing \
+            --with-includes="${POISONED_HEADERS}" \
             \
             ${LINUX_CONFIGURE_FEATURES} \
             \
@@ -540,6 +556,7 @@ task:
     # - Test both 64bit and 32 bit builds
     # - uses io_method=io_uring
     # - Uses meson feature autodetection
+    # - Poisoned headers in search path
     - name: Linux - Debian Bookworm - Meson
 
       env:
@@ -552,6 +569,7 @@ task:
         su postgres <<-EOF
           meson setup \
             ${MESON_COMMON_PG_CONFIG_ARGS} \
+            -Dextra_include_dirs="${POISONED_HEADERS}" \
             --buildtype=debug \
             ${LINUX_MESON_FEATURES} -Dllvm=enabled \
             build
@@ -564,6 +582,7 @@ task:
           export CC='ccache gcc -m32'
           meson setup \
             ${MESON_COMMON_PG_CONFIG_ARGS} \
+            -Dextra_include_dirs="${POISONED_HEADERS}" \
             --buildtype=debug \
             --pkg-config-path /usr/lib/i386-linux-gnu/pkgconfig/ \
             -DPERL=perl5.36-i386-linux-gnu \
@@ -573,12 +592,14 @@ task:
 
       build_script: |
         su postgres <<-EOF
+          set -e
           ninja -C build -j${BUILD_JOBS} ${MBUILD_TARGET}
           ninja -C build -t missingdeps
         EOF
 
       build_32_script: |
         su postgres <<-EOF
+          set -e
           ninja -C build-32 -j${BUILD_JOBS} ${MBUILD_TARGET}
           ninja -C build -t missingdeps
         EOF
-- 
2.51.1

From 290bf24a89a075f3380c7e9af03d357475718887 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Tue, 4 Nov 2025 03:09:22 +1300
Subject: [PATCH v4 3/4] meson: Try to find libintl without -Dextra_XXX.

Since libintl is the only dependency that Meson can't usually find via
pkg-config on typical non-Linux Unix systems, let's try a bit harder to
find it with existing clues.

We typically find msgfmt in $PATH, so we can plausibly guess that the
library and headers are installed in the same prefix, and then try that
before giving up and requiring a manual path configuration.

This revealed some missing dependency declarations previously covered by
the catch-all extra_includes_dir, added here.

XXX Is this a terrible idea for some reason?
---
 meson.build                            | 34 +++++++++++++++++++++-----
 src/backend/jit/llvm/meson.build       |  5 +++-
 src/interfaces/libpq-oauth/meson.build |  1 +
 src/port/meson.build                   |  6 ++---
 4 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/meson.build b/meson.build
index 0f61ff6a700..2690d7a7b2b 100644
--- a/meson.build
+++ b/meson.build
@@ -2973,6 +2973,7 @@ cdata.set_quoted('PG_VERSION_STR',
 
 nlsopt = get_option('nls')
 libintl = not_found_dep
+libintl_include_dirs = []
 
 if not nlsopt.disabled()
   # otherwise there'd be lots of
@@ -2982,7 +2983,7 @@ if not nlsopt.disabled()
 
   # meson 0.59 has this wrapped in dependency('intl')
   if (msgfmt.found() and
-      cc.check_header('libintl.h', required: nlsopt,
+      cc.check_header('libintl.h',
         args: test_c_args, include_directories: postgres_inc))
 
     # in libc
@@ -2990,13 +2991,34 @@ if not nlsopt.disabled()
       libintl = declare_dependency()
     else
       libintl = cc.find_library('intl',
-        has_headers: ['libintl.h'], required: nlsopt,
+        has_headers: ['libintl.h'],
         header_include_directories: postgres_inc,
         dirs: test_lib_d)
     endif
   endif
 
+  if (msgfmt.found() and not libintl.found())
+    # libintl doesn't provide libintl.pc, but since we found its companion
+    # binary msgfmt we have a solid clue where to look, assuming standard
+    # layout within the install prefix.
+    guess_libintl_prefix = fs.parent(fs.parent(msgfmt.full_path()))
+    guess_libintl_lib_d = guess_libintl_prefix / 'lib'
+    guess_libintl_include = guess_libintl_prefix / 'include'
+    guess_libintl_include_dirs = include_directories(guess_libintl_include)
+    libintl_lib = cc.find_library('intl',
+      has_headers: ['libintl.h'],
+      header_include_directories: guess_libintl_include_dirs,
+      dirs: guess_libintl_lib_d)
+    if libintl_lib.found()
+      libintl = declare_dependency(dependencies: libintl_lib,
+                                   include_directories: guess_libintl_include_dirs)
+      libintl_include_dirs += guess_libintl_include # needed for llvmjit_types.bc
+    endif
+  endif
+
   if libintl.found()
+    cc.check_header('libintl.h', required: nlsopt,
+      args: test_c_args, include_directories: postgres_inc, dependencies: libintl)
     i18n = import('i18n')
     cdata.set('ENABLE_NLS', 1)
   endif
@@ -3220,14 +3242,14 @@ subdir('config')
 frontend_port_code = declare_dependency(
   compile_args: ['-DFRONTEND'],
   include_directories: [postgres_inc],
-  dependencies: os_deps,
+  dependencies: [os_deps, libintl]
 )
 
 backend_port_code = declare_dependency(
   compile_args: ['-DBUILDING_DLL'],
   include_directories: [postgres_inc],
   sources: [errcodes], # errcodes.h is needed due to use of ereport
-  dependencies: os_deps,
+  dependencies: [os_deps, libintl]
 )
 
 subdir('src/port')
@@ -3236,14 +3258,14 @@ frontend_common_code = declare_dependency(
   compile_args: ['-DFRONTEND'],
   include_directories: [postgres_inc],
   sources: generated_headers_stamp,
-  dependencies: [os_deps, zlib, zstd, lz4],
+  dependencies: [os_deps, libintl, zlib, zstd, lz4],
 )
 
 backend_common_code = declare_dependency(
   compile_args: ['-DBUILDING_DLL'],
   include_directories: [postgres_inc],
   sources: generated_headers_stamp,
-  dependencies: [os_deps, zlib, zstd],
+  dependencies: [os_deps, libintl, zlib, zstd],
 )
 
 subdir('src/common')
diff --git a/src/backend/jit/llvm/meson.build b/src/backend/jit/llvm/meson.build
index 805fbd69006..bcc5efed8a2 100644
--- a/src/backend/jit/llvm/meson.build
+++ b/src/backend/jit/llvm/meson.build
@@ -32,7 +32,7 @@ endif
 llvmjit = shared_module('llvmjit',
   llvmjit_sources,
   kwargs: pg_mod_args + {
-    'dependencies': pg_mod_args['dependencies'] + [llvm],
+    'dependencies': pg_mod_args['dependencies'] + [llvm, libintl],
     'cpp_args': pg_mod_args['cpp_args'] + llvm.get_variable(configtool: 'cxxflags').split(),
   }
 )
@@ -69,6 +69,9 @@ bitcode_cflags += '-I@BUILD_ROOT@/src/include'
 bitcode_cflags += '-I@BUILD_ROOT@/src/backend/utils/misc'
 bitcode_cflags += '-I@SOURCE_ROOT@/src/include'
 
+foreach d : libintl_include_dirs
+  bitcode_cflags += ['-I' + d]
+endforeach
 
 # Note this is intentionally not installed to bitcodedir, as it's not for
 # inlining
diff --git a/src/interfaces/libpq-oauth/meson.build b/src/interfaces/libpq-oauth/meson.build
index 505e1671b86..9d7fa1bc67c 100644
--- a/src/interfaces/libpq-oauth/meson.build
+++ b/src/interfaces/libpq-oauth/meson.build
@@ -29,6 +29,7 @@ libpq_oauth_st = static_library('libpq-oauth',
     frontend_stlib_code,
     libpq_oauth_deps,
     ssl, # libpq-int.h includes OpenSSL headers
+    gssapi, # and gssapi
   ],
   kwargs: default_lib_args,
 )
diff --git a/src/port/meson.build b/src/port/meson.build
index fc7b059fee5..9c4f5459e0a 100644
--- a/src/port/meson.build
+++ b/src/port/meson.build
@@ -154,14 +154,14 @@ endif
 pgport = {}
 pgport_variants = {
   '_srv': internal_lib_args + {
-    'dependencies': [backend_port_code],
+    'dependencies': [backend_port_code, libintl],
   },
   '': default_lib_args + {
-    'dependencies': [frontend_port_code],
+    'dependencies': [frontend_port_code, libintl],
   },
   '_shlib': default_lib_args + {
     'pic': true,
-    'dependencies': [frontend_port_code],
+    'dependencies': [frontend_port_code, libintl],
   },
 }
 
-- 
2.51.1

From e553e694574113cd0ddf9b07af7ebc8bbaa8e246 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Tue, 4 Nov 2025 12:47:41 +1300
Subject: [PATCH v4 4/4] ci: Remove -Dextra_XXX on FreeBSD and macOS.

Since FreeBSD and MacPorts install .pc files for the libraries want,
Meson can find them.  The only exception is libintl, which the previous
commit handled specially.

NetBSD has its own libintl in libc, and OpenBSD doesn't have nls
enabled, explaining why they didn't need -Dextra_include_dirs and
-Dextra_lib_dirs in the first place.  The Windows task still needs them
to find OpenSSL.
---
 .cirrus.tasks.yml | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/.cirrus.tasks.yml b/.cirrus.tasks.yml
index 3df6de6acd9..31e498dc9b9 100644
--- a/.cirrus.tasks.yml
+++ b/.cirrus.tasks.yml
@@ -232,7 +232,6 @@ task:
       meson setup \
         ${MESON_COMMON_PG_CONFIG_ARGS} \
         --buildtype=debug \
-        -Dextra_lib_dirs=/usr/local/lib -Dextra_include_dirs=/usr/local/include/ \
         ${MESON_COMMON_FEATURES} ${MESON_FEATURES} \
         build
     EOF
@@ -731,8 +730,6 @@ task:
     meson setup \
       ${MESON_COMMON_PG_CONFIG_ARGS} \
       --buildtype=debug \
-      -Dextra_include_dirs=/opt/local/include \
-      -Dextra_lib_dirs=/opt/local/lib \
       ${MESON_COMMON_FEATURES} ${MESON_FEATURES} \
       build
 
-- 
2.51.1

diff --git i/meson.build w/meson.build
index 0f61ff6a700..31ef82a52a4 100644
--- i/meson.build
+++ w/meson.build
@@ -84,7 +84,6 @@ endif
 ###############################################################
 
 postgres_inc_d = ['src/include']
-postgres_inc_d += get_option('extra_include_dirs')
 
 postgres_lib_d = get_option('extra_lib_dirs')
 
@@ -327,6 +326,23 @@ else
   error('unknown host system: @0@'.format(host_system))
 endif
 
+# While the most obvious way to implement extra_include_dirs would be to add
+# extra_include_dirs to postgres_inc_d, that turns out to not work well: For
+# some parts of the buildtree (e.g. src/interfaces/libpq or tools linking
+# against libpq) we need to add additional directories to be included, and
+# those directories need to take precedence over extra_include_dirs.  The
+# easiest way to achieve that is to gin up the compiler arguments ourselves
+# (which luckily is the same across all supported compilers) and add it to
+# cppflags. That works as meson always adds explicit include_directories
+# before generic compiler arguments.
+#
+# An additional advantage is that this way the extra include directories are
+# included in pg_config --cppflags output, keeping the behavior consistent
+# with autoconf builds.
+foreach extra_dir : get_option('extra_include_dirs')
+  cppflags += '-I@0@'.format(extra_dir)
+endforeach
+
 
 
 ###############################################################