ENH: add support for removing build time RPATH entries

Requires Meson 1.9.0.

Author: dnicolodi

docs/reference/meson-compatibility.rst

@@ -61,6 +61,12 @@ versions.
 
    Meson 1.9.0 or later is required to support building for iOS.
 
+   Meson 1.9.0 or later is also required to remove RPATH entries that
+   are added by Meson to allow to execute parts of the project from
+   the build directory and that are normally removed during ``meson
+   install``. On older Meson versions, these entries are not removed,
+   but this should not have any adverse effect.
+
 Build front-ends by default build packages in an isolated Python
 environment where build dependencies are installed. Most often, unless
 a package or its build dependencies declare explicitly a version

mesonpy/__init__.py

@@ -129,6 +129,8 @@ class _Entry(typing.NamedTuple):
     # list to store install RPATH to be able to add append more
     # entries when needed.
     install_rpath: List[str] = []
+    # RPATH entries to remove at install time.
+    build_rpath: List[str] = []
 
 
 def _map_to_wheel(
@@ -188,7 +190,8 @@ def _map_to_wheel(
                         wheel_files[path].append(_Entry(filedst, filesrc))
             else:
                 install_rpath = target.get('install_rpath')
-                wheel_files[path].append(_Entry(dst, src, [install_rpath] if install_rpath else []))
+                build_rpath = target.get('build_rpaths')
+                wheel_files[path].append(_Entry(dst, src, [install_rpath] if install_rpath else [], build_rpath or []))
 
     return wheel_files
 
@@ -454,15 +457,16 @@ def _stable_abi(self) -> Optional[str]:
             return 'abi3.abi3t' if abi3t else 'abi3'
         return None
 
-    def _install_path(self, wheel_file: mesonpy._wheelfile.WheelFile, origin: Path, destination: pathlib.Path,
-                      install_rpath: List[str]) -> None:
+    def _install_path(self, wheel_file: mesonpy._wheelfile.WheelFile,
+                      origin: Path, destination: pathlib.Path,
+                      install_rpath: List[str], build_rpath: List[str]) -> None:
         """Add a file to the wheel."""
 
         if self._has_internal_libs and _is_native(origin):
             libspath = os.path.relpath(self._libs_dir, destination.parent)
-            mesonpy._rpath.fix_rpath(origin, install_rpath, libspath)
-        elif install_rpath:
-            mesonpy._rpath.fix_rpath(origin, install_rpath, None)
+            mesonpy._rpath.fix_rpath(origin, install_rpath, build_rpath, libspath)
+        elif install_rpath or build_rpath:
+            mesonpy._rpath.fix_rpath(origin, install_rpath, build_rpath, None)
 
         try:
             wheel_file.write(origin, destination.as_posix())
@@ -506,7 +510,7 @@ def build(self, directory: Path) -> pathlib.Path:
                 root = 'purelib' if self._pure else 'platlib'
 
                 for path, entries in self._manifest.items():
-                    for dst, src, install_rpath in entries:
+                    for dst, src, install_rpath, build_rpath in entries:
                         counter.update(src)
 
                         if path == root:
@@ -517,7 +521,7 @@ def build(self, directory: Path) -> pathlib.Path:
                         else:
                             dst = pathlib.Path(self._data_dir, path, dst)
 
-                        self._install_path(whl, src, dst, install_rpath)
+                        self._install_path(whl, src, dst, install_rpath, build_rpath)
 
         return wheel_file
 

mesonpy/_rpath.py

@@ -37,9 +37,14 @@ def set_rpath(filepath: Path, old: List[str], rpath: List[str]) -> None:
         raise NotImplementedError
 
     @classmethod
-    def fix_rpath(cls, filepath: Path, install_rpath: List[str], libs_relative_path: Optional[str]) -> None:
+    def fix_rpath(cls, filepath: Path, add: List[str], remove: List[str], libs_relative_path: Optional[str]) -> None:
         old_rpath = cls.get_rpath(filepath)
-        new_rpath = old_rpath[:]
+
+        # Meson adds a padding entry to RPATH composed of enough `X`
+        # characters to reserve enough space in the ELF header to hold
+        # the final installation RPATH. Remove this entry and other
+        # entries to be removed.
+        new_rpath = [path for path in old_rpath if path.strip('X') and path not in remove]
 
         # When an executable, libray, or Python extension module is
         # dynamically linked to a library built as part of the project, Meson
@@ -55,7 +60,7 @@ def fix_rpath(cls, filepath: Path, install_rpath: List[str], libs_relative_path:
             new_rpath.append(os.path.join(cls.origin, libs_relative_path))
 
         # Add install_rpath.
-        new_rpath += install_rpath
+        new_rpath += add
 
         new_rpath = unique(new_rpath)
         if new_rpath != old_rpath:
@@ -65,7 +70,7 @@ def fix_rpath(cls, filepath: Path, install_rpath: List[str], libs_relative_path:
 class _Windows(RPATH):
 
     @classmethod
-    def fix_rpath(cls, filepath: Path, install_rpath: List[str], libs_relative_path: str) -> None:
+    def fix_rpath(cls, filepath: Path, add: List[str], remove: List[str], libs_relative_path: Optional[str]) -> None:
         pass
 
 

tests/test_wheel.py

@@ -43,6 +43,9 @@
 INTERPRETER = tag.interpreter
 PLATFORM = adjust_packaging_platform_tag(tag.platform)
 
+# Support for removing build RPATH entries requires Meson 1.9 or later.
+BUILD_RPATH_SUPPORT = MESON_VERSION >= (1, 9)
+
 
 def wheel_contents(artifact):
     # Sometimes directories have entries, sometimes not, so we filter them out.
@@ -186,12 +189,14 @@ def test_sharedlib_in_package_rpath(wheel_sharedlib_in_package, tmp_path):
     origin = '@loader_path' if sys.platform == 'darwin' else '$ORIGIN'
 
     rpath = set(mesonpy._rpath.get_rpath(tmp_path / 'mypkg' / f'_example{EXT_SUFFIX}'))
-    # FIXME: RPATH entries added by Meson to point to the build directory are not removed.
     assert rpath >= {origin}
+    if BUILD_RPATH_SUPPORT:
+        assert rpath == {origin}
 
     rpath = set(mesonpy._rpath.get_rpath(tmp_path / 'mypkg' / f'liblib{LIB_SUFFIX}'))
-    # FIXME: RPATH entries added by Meson to point to the build directory are not removed.
     assert rpath >= {f'{origin}/sub'}
+    if BUILD_RPATH_SUPPORT:
+        assert rpath == {f'{origin}/sub'}
 
     rpath = set(mesonpy._rpath.get_rpath(tmp_path / 'mypkg' / 'sub' / f'libsublib{LIB_SUFFIX}'))
     assert rpath == set()
@@ -235,8 +240,9 @@ def test_link_against_local_lib_rpath(wheel_link_against_local_lib, tmp_path):
     expected = {f'{origin}/../.link_against_local_lib.mesonpy.libs', 'custom-rpath',}
 
     rpath = set(mesonpy._rpath.get_rpath(tmp_path / 'example' / f'_example{EXT_SUFFIX}'))
-    # FIXME: RPATH entries added by Meson to point to the build directory are not removed.
     assert rpath >= expected
+    if BUILD_RPATH_SUPPORT:
+        assert rpath == expected
 
 
 @pytest.mark.skipif(sys.platform in {'win32', 'cygwin'}, reason='requires RPATH support')