bpo-45743: -Wl,-search_paths_first is no longer needed (GH-29464)

Misc/NEWS.d/next/Build/2021-11-08-08-58-06.bpo-45743.fZ8CTi.rst

@@ -0,0 +1,2 @@
+On macOS, the build system no longer passes ``search_paths_first`` to the
+linker. The flag has been the default since Xcode 4 / macOS 10.6.

configure

@@ -12886,15 +12886,6 @@ $as_echo "#define HAVE_LCHFLAGS 1" >>confdefs.h
 fi
 
 # Check for compression libraries
-case $ac_sys_system/$ac_sys_release in
-Darwin/*)
-	_CUR_CFLAGS="${CFLAGS}"
-	_CUR_LDFLAGS="${LDFLAGS}"
-	CFLAGS="${CFLAGS} -Wl,-search_paths_first"
-	LDFLAGS="${LDFLAGS} -Wl,-search_paths_first -L/usr/local/lib"
-	;;
-esac
-
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for inflateCopy in -lz" >&5
 $as_echo_n "checking for inflateCopy in -lz... " >&6; }
 if ${ac_cv_lib_z_inflateCopy+:} false; then :
@@ -12938,13 +12929,6 @@ $as_echo "#define HAVE_ZLIB_COPY 1" >>confdefs.h
 fi
 
 
-case $ac_sys_system/$ac_sys_release in
-Darwin/*)
-	CFLAGS="${_CUR_CFLAGS}"
-	LDFLAGS="${_CUR_LDFLAGS}"
-	;;
-esac
-
 
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for hstrerror" >&5

configure.ac

@@ -3833,34 +3833,8 @@ fi
 
 # Check for compression libraries
 dnl Check if system zlib has *Copy() functions
-dnl
-dnl On MacOSX the linker will search for dylibs on the entire linker path
-dnl before searching for static libraries. setup.py adds -Wl,-search_paths_first
-dnl to revert to a more traditional unix behaviour and make it possible to
-dnl override the system libz with a local static library of libz. Temporarily
-dnl add that flag to our CFLAGS as well to ensure that we check the version
-dnl of libz that will be used by setup.py.
-dnl The -L/usr/local/lib is needed as wel to get the same compilation
-dnl environment as setup.py (and leaving it out can cause configure to use the
-dnl wrong version of the library)
-case $ac_sys_system/$ac_sys_release in
-Darwin/*)
-	_CUR_CFLAGS="${CFLAGS}"
-	_CUR_LDFLAGS="${LDFLAGS}"
-	CFLAGS="${CFLAGS} -Wl,-search_paths_first"
-	LDFLAGS="${LDFLAGS} -Wl,-search_paths_first -L/usr/local/lib"
-	;;
-esac
-
 AC_CHECK_LIB(z, inflateCopy, AC_DEFINE(HAVE_ZLIB_COPY, 1, [Define if the zlib library has inflateCopy]))
 
-case $ac_sys_system/$ac_sys_release in
-Darwin/*)
-	CFLAGS="${_CUR_CFLAGS}"
-	LDFLAGS="${_CUR_LDFLAGS}"
-	;;
-esac
-
 PY_CHECK_FUNC([hstrerror], [#include <netdb.h>])
 
 PY_CHECK_FUNC([inet_aton], [

setup.py

@@ -1118,16 +1118,6 @@ class PyBuildExt(build_ext):
                 if find_file('readline/rlconf.h', self.inc_dirs, []) is None:
                     do_readline = False
         if do_readline:
-            if MACOS and os_release < 9:
-                # In every directory on the search path search for a dynamic
-                # library and then a static library, instead of first looking
-                # for dynamic libraries on the entire path.
-                # This way a statically linked custom readline gets picked up
-                # before the (possibly broken) dynamic library in /usr/lib.
-                readline_extra_link_args = ('-Wl,-search_paths_first',)
-            else:
-                readline_extra_link_args = ()
-
             readline_libs = [readline_lib]
             if readline_termcap_library:
                 pass # Issue 7384: Already linked against curses or tinfo.
@@ -1139,7 +1129,6 @@ class PyBuildExt(build_ext):
                 readline_libs.append('termcap')
             self.add(Extension('readline', ['readline.c'],
                                library_dirs=['/usr/lib/termcap'],
-                               extra_link_args=readline_extra_link_args,
                                libraries=readline_libs))
         else:
             self.missing.append('readline')
@@ -1603,16 +1592,6 @@ class PyBuildExt(build_ext):
             ):
                 raise DistutilsError("System version of SQLite does not support loadable extensions")
 
-            if MACOS:
-                # In every directory on the search path search for a dynamic
-                # library and then a static library, instead of first looking
-                # for dynamic libraries on the entire path.
-                # This way a statically linked custom sqlite gets picked up
-                # before the dynamic library in /usr/lib.
-                sqlite_extra_link_args = ('-Wl,-search_paths_first',)
-            else:
-                sqlite_extra_link_args = ()
-
             include_dirs = ["Modules/_sqlite"]
             # Only include the directory where sqlite was found if it does
             # not already exist in set include directories, otherwise you
@@ -1626,7 +1605,6 @@ class PyBuildExt(build_ext):
                                define_macros=sqlite_defines,
                                include_dirs=include_dirs,
                                library_dirs=sqlite_libdir,
-                               extra_link_args=sqlite_extra_link_args,
                                libraries=["sqlite3",]))
         else:
             self.missing.append('_sqlite3')
@@ -1685,13 +1663,8 @@ class PyBuildExt(build_ext):
                         break
             if version >= version_req:
                 if (self.compiler.find_library_file(self.lib_dirs, 'z')):
-                    if MACOS:
-                        zlib_extra_link_args = ('-Wl,-search_paths_first',)
-                    else:
-                        zlib_extra_link_args = ()
                     self.add(Extension('zlib', ['zlibmodule.c'],
-                                       libraries=['z'],
+                                       libraries=['z']))
-                                       extra_link_args=zlib_extra_link_args))
                     have_zlib = True
                 else:
                     self.missing.append('zlib')
@@ -1706,24 +1679,16 @@ class PyBuildExt(build_ext):
         if have_zlib:
             extra_compile_args.append('-DUSE_ZLIB_CRC32')
             libraries = ['z']
-            extra_link_args = zlib_extra_link_args
         else:
             libraries = []
-            extra_link_args = []
         self.add(Extension('binascii', ['binascii.c'],
                            extra_compile_args=extra_compile_args,
-                           libraries=libraries,
+                           libraries=libraries))
-                           extra_link_args=extra_link_args))
 
         # Gustavo Niemeyer's bz2 module.
         if (self.compiler.find_library_file(self.lib_dirs, 'bz2')):
-            if MACOS:
-                bz2_extra_link_args = ('-Wl,-search_paths_first',)
-            else:
-                bz2_extra_link_args = ()
             self.add(Extension('_bz2', ['_bz2module.c'],
-                               libraries=['bz2'],
+                               libraries=['bz2']))
-                               extra_link_args=bz2_extra_link_args))
         else:
             self.missing.append('_bz2')