Python package: fix .libs on macOS with external Python (#33410)

For some instances of externally-provided Python (e.g. Homebrew),
the LDLIBRARY/LIBRARY config variables don't actually refer to
libraries and should therefore be excluded from ".libs".

1 files changed, 21 insertions, 4 deletions

diff --git a/var/spack/repos/builtin/packages/python/package.py b/var/spack/repos/builtin/packages/python/package.py
index 8a69efbbda..3fea87a2ec 100644
--- a/var/spack/repos/builtin/packages/python/package.py
+++ b/var/spack/repos/builtin/packages/python/package.py
@@ -1250,12 +1250,29 @@ config.update(get_paths())
         # The values of LDLIBRARY and LIBRARY aren't reliable. Intel Python uses a
         # static binary but installs shared libraries, so sysconfig reports
         # libpythonX.Y.a but only libpythonX.Y.so exists. So we add our own paths, too.
-        shared_libs = [
-            self.config_vars["LDLIBRARY"],
+
+        # With framework python on macOS, self.config_vars["LDLIBRARY"] can point
+        # to a library that is not linkable because it does not have the required
+        # suffix of a shared library (it is called "Python" without extention).
+        # The linker then falls back to libPython.tbd in the default macOS
+        # software tree, which security settings prohibit to link against
+        # (your binary is not an allowed client of /path/to/libPython.tbd).
+        # To avoid this, we replace the entry in config_vars with a default value.
+        file_extension_shared = os.path.splitext(self.config_vars["LDLIBRARY"])[-1]
+        if file_extension_shared == "":
+            shared_libs = []
+        else:
+            shared_libs = [self.config_vars["LDLIBRARY"]]
+        shared_libs += [
             "{}python{}.{}".format(lib_prefix, py_version, dso_suffix),
         ]
-        static_libs = [
-            self.config_vars["LIBRARY"],
+        # Like LDLIBRARY for Python on Mac OS, LIBRARY may refer to an un-linkable object
+        file_extension_static = os.path.splitext(self.config_vars["LIBRARY"])[-1]
+        if file_extension_static == "":
+            static_libs = []
+        else:
+            static_libs = [self.config_vars["LIBRARY"]]
+        static_libs += [
             "{}python{}.{}".format(lib_prefix, py_version, stat_suffix),
         ]