Duplicate entries in RPATH

When building with meson python on a recent version of macOS I can no longer import my module.

import gridfire

ImportError: dlopen(/opt/homebrew/anaconda3/envs/fourdstar/lib/python3.13/site-packages/gridfire.cpython-313-darwin.so, 0x0002): tried: '/opt/homebrew/anaconda3/envs/fourdstar/lib/python3.13/site-packages/gridfire.cpython-313-darwin.so' (duplicate LC_RPATH '@loader_path/.gridfire.mesonpy.libs'), '/System/Volumes/Preboot/Cryptexes/OS/opt/homebrew/anaconda3/envs/fourdstar/lib/python3.13/site-packages/gridfire.cpython-313-darwin.so' (no such file), '/opt/homebrew/anaconda3/envs/fourdstar/lib/python3.13/site-packages/gridfire.cpython-313-darwin.so' (duplicate LC_RPATH '@loader_path/.gridfire.mesonpy.libs')

When I inspect the shared object file with otool I see that it contains many duplicate LC_RPATH entries

otool -l gridfire.cpython-313-darwin.so | grep RPATH -A2

          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path @loader_path/.gridfire.mesonpy.libs (offset 12)
--
          cmd LC_RPATH
      cmdsize 56
         path /opt/homebrew/Cellar/openssl@3/3.5.2/lib (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path /opt/homebrew/Cellar/xz/5.8.1/lib (offset 12)
--
          cmd LC_RPATH
      cmdsize 40
         path /opt/homebrew/opt/zstd/lib (offset 12)

If I manually remove all but one of the rpath instances using install_name_tool

install_name_tool -delete_rpath @loader_path/.gridfire.mesonpy.libs

Then I can import and use my module just fine. Presumably then I could write some somewhat convoluted but not too complex tool to use otool to count the number of duplicate paths and remove them; however, I'm sure this strikes me as a one-way street to a bad time (lack of portability, and just a generally convoluted build step).

Other discussions (https://github.com/facebook/zstd/issues/4369, https://fenicsproject.discourse.group/t/duplicate-lc-rpath-errors-on-macos-15-4-sequoia/17364) have pinpointed this change in behavior with recent versions of apple's XCode command line tools. Specifically that duplicate lc_rpaths are now treated as an error when loading shared libraries.

My question then is how do I prevent meson-python from adding all these duplicate paths to the shared object file?

Details

• macOS Version 26.0.1
• CLITools version : 26.0.0.0.1.1757719676
• meson-python version: 0.18.0
• meson version: 1.9.1
• clang version: Apple clang 17.0.0 (clang-1700.3.19.1)

Other details

• I have tried building with pip install . --no-cache-dir and pip install . --no-cache-dir --isolated and neither of these make a difference.
• I have confirmed the same behavior in my other mesonpy library, fourdst. I see the same behavior there where if I remove all but one of the rpath's using install_name_tool then I can import and use the module just fine
• When I inspect the shared library created by meson (which I belive is generated before meson-python steps in, though I may be mistaken, there are no duplicate lc_rpaths).

otool -l libgridfire.dylib | grep RPATH -A2

          cmd LC_RPATH
      cmdsize 72
         path @loader_path/../subprojects/libconstants/src/constants (offset 12)
--
          cmd LC_RPATH
      cmdsize 64
         path @loader_path/../subprojects/libconfig/src/config (offset 12)
--
          cmd LC_RPATH
      cmdsize 56
         path @loader_path/../subprojects/yaml-cpp (offset 12)
--
          cmd LC_RPATH
      cmdsize 72
         path @loader_path/../subprojects/libcomposition/src/composition (offset 12)
--
          cmd LC_RPATH
      cmdsize 64
         path @loader_path/../subprojects/liblogging/src/logging (offset 12)
--
          cmd LC_RPATH
      cmdsize 56
         path @loader_path/../subprojects/libplugin/src (offset 12)
--
          cmd LC_RPATH
      cmdsize 64
         path @loader_path/../subprojects/minizip-ng-4.0.10 (offset 12)
--
          cmd LC_RPATH
      cmdsize 56
         path @loader_path/../subprojects/cvode-7.3.0 (offset 12)
--
          cmd LC_RPATH
      cmdsize 56
         path /opt/homebrew/Cellar/openssl@3/3.5.2/lib (offset 12)
--
          cmd LC_RPATH
      cmdsize 48
         path /opt/homebrew/Cellar/xz/5.8.1/lib (offset 12)
--
          cmd LC_RPATH
      cmdsize 40
         path /opt/homebrew/opt/zstd/lib (offset 12)

Originally reported by @tboudreaux in https://github.com/mesonbuild/meson-python/discussions/812

Inizia riproducendo la build macOS e confrontando l'output di otool per libgridfire.dylib con quello di gridfire.cpython-313-darwin.so installata. Traccia il percorso di build/installazione di meson-python che aggiunge @loader_path/.gridfire.mesonpy.libs e determina dove si originano i duplicati. Il lavoro è completato quando l'estensione installata non contiene voci LC_RPATH duplicate e viene importata correttamente senza modifiche manuali con install_name_tool.