ENH: do not remove absolute build RPATH entries

.github/workflows/pixi.toml

@@ -19,14 +19,21 @@ ninja = "*"
 pkg-config = "*"
 cmake = "*"
 patchelf = "*"
-c-compiler = "*"
-cxx-compiler = "*"
+geos = "*"
 pip = "*"
 python-build = "*"
 cython = "*"
 pytest = "*"
 pytest-mock = "*"
 wheel = "*"
 
+[feature.compilers.dependencies]
+c-compiler = "*"
+cxx-compiler = "*"
+
+[environments]
+default = { features = ["compilers"], solve-group = "test" }
+system-compilers = { features = [], solve-group = "test" }
+
 [tasks]
 test = { cmd = "pytest", cwd = "../.." }

.github/workflows/tests.yml

@@ -336,7 +336,16 @@ jobs:
         run: mypy -p mesonpy
 
   pixi:
+    name: ${{ matrix.name }}
     runs-on: ubuntu-24.04-arm
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: pixi
+            environment: default
+          - name: pixi-system-compilers
+            environment: system-compilers
     steps:
       - name: Checkout
         uses: actions/checkout@v7
@@ -347,11 +356,12 @@ jobs:
         with:
           pixi-version: v0.77.1
           manifest-path: .github/workflows/pixi.toml
+          environments: ${{ matrix.environment }}
           cache: false
 
       - name: Run tests
         working-directory: .github/workflows
-        run: pixi run test
+        run: pixi run --environment ${{ matrix.environment }} test
 
   uv-sync:
     runs-on: ubuntu-latest

mesonpy/__init__.py

@@ -206,6 +206,16 @@ def _map_to_wheel(sources: Dict[str, Dict[str, Any]],
                 if sys.platform == 'darwin':
                     install_rpath = [_translate_rpath(path, dst) for path in install_rpath]
 
+                # Remove absolute paths from ``build_rpath``.  Meson adds
+                # RPATH entries for shared libraries compiled as part of the
+                # project and shared libraries from dependencies installed in
+                # non-standard locations.  The first are relative paths using
+                # the ``$ORIGIN`` or ``@loader_path`` anchor.  The seconds are
+                # absolute paths.  For the resulting binaries to be able to
+                # dynamically link to local dependencies, we want to remove
+                # the first but keep the seconds.
+                build_rpath = [path for path in build_rpath if not path.startswith('/')]
+
                 wheel_files[path].append(_Entry(dst, src, install_rpath, build_rpath))
 
     return wheel_files

tests/packages/link-against-external-lib/external.c

@@ -0,0 +1,23 @@
+// SPDX-FileCopyrightText: 2026 The meson-python developers
+//
+// SPDX-License-Identifier: MIT
+
+#include <Python.h>
+#include <geos_c.h>
+
+static PyObject *version(PyObject *self, PyObject *args) {
+    return PyUnicode_FromString(GEOSversion());
+}
+
+static PyMethodDef methods[] = {
+    {"version", version, METH_NOARGS, NULL},
+    {NULL, NULL, 0, NULL},
+};
+
+static struct PyModuleDef module = {
+    PyModuleDef_HEAD_INIT, "external", NULL, -1, methods,
+};
+
+PyMODINIT_FUNC PyInit_external(void) {
+    return PyModule_Create(&module);
+}

tests/packages/link-against-external-lib/meson.build

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: 2026 The meson-python developers
+#
+# SPDX-License-Identifier: MIT
+
+project('link-against-external-lib', 'c', version: '1.0.0')
+
+py = import('python').find_installation(pure: false)
+
+external = dependency('geos', method: 'pkg-config')
+
+py.extension_module(
+    'external',
+    'external.c',
+    dependencies: external,
+    install: true
+)

tests/packages/link-against-external-lib/pyproject.toml

@@ -0,0 +1,7 @@
+# SPDX-FileCopyrightText: 2026 The meson-python developers
+#
+# SPDX-License-Identifier: MIT
+
+[build-system]
+build-backend = 'mesonpy'
+requires = ['meson-python']

tests/test_wheel.py

@@ -6,6 +6,7 @@
 import re
 import shutil
 import stat
+import subprocess
 import sys
 import textwrap
 
@@ -260,6 +261,22 @@ def check(rpath, *expected):
     check(rpath, 'custom-rpath', f'{origin}/../.link_against_local_lib.mesonpy.libs')
 
 
+@pytest.mark.skipif(sys.platform in {'win32', 'cygwin'}, reason='requires RPATH support')
+@pytest.mark.skipif(shutil.which('pkg-config') is None, reason='requires pkg-config')
+def test_link_against_external_lib_rpath(package_link_against_external_lib, tmp_path, venv):
+    if subprocess.run(['pkg-config', '--exists', 'geos']).returncode:
+        pytest.skip('requires GEOS')
+    version = subprocess.check_output(['pkg-config', '--modversion', 'geos'], text=True).strip()
+
+    # Use an installed dependency without supplying an explicit RPATH.
+    # Check its version too, to detect fallback to a different system copy.
+    filename = mesonpy.build_wheel(tmp_path)
+    venv.pip('install', tmp_path / filename)
+    output = venv.python('-c', 'import external; print(external.version())')
+    # GEOSversion() appends the C API version after "-CAPI-".
+    assert output.strip().split('-CAPI-')[0] == version
+
+
 @pytest.mark.skipif(sys.platform in {'win32', 'cygwin'}, reason='requires RPATH support')
 def test_link_against_local_lib_rpath_ldflags(package_link_against_local_lib, tmp_path, monkeypatch):
     origin = '@loader_path' if sys.platform == 'darwin' else '$ORIGIN'