Issue #18080: merge from 3.3

Lib/distutils/sysconfig.py

@@ -188,9 +188,15 @@ def customize_compiler(compiler):
             get_config_vars('CC', 'CXX', 'OPT', 'CFLAGS',
                             'CCSHARED', 'LDSHARED', 'SHLIB_SUFFIX', 'AR', 'ARFLAGS')
 
-        newcc = None
         if 'CC' in os.environ:
-            cc = os.environ['CC']
+            newcc = os.environ['CC']
+            if (sys.platform == 'darwin'
+                    and 'LDSHARED' not in os.environ
+                    and ldshared.startswith(cc)):
+                # On OS X, if CC is overridden, use that as the default
+                #       command for LDSHARED as well
+                ldshared = newcc + ldshared[len(cc):]
+            cc = newcc
         if 'CXX' in os.environ:
             cxx = os.environ['CXX']
         if 'LDSHARED' in os.environ:

Lib/distutils/tests/test_unixccompiler.py

@@ -1,7 +1,8 @@
 """Tests for distutils.unixccompiler."""
+import os
 import sys
 import unittest
-from test.support import run_unittest
+from test.support import EnvironmentVarGuard, run_unittest
 
 from distutils import sysconfig
 from distutils.unixccompiler import UnixCCompiler
@@ -94,7 +95,6 @@ class UnixCCompilerTestCase(unittest.TestCase):
         sysconfig.get_config_var = gcv
         self.assertEqual(self.cc.rpath_foo(), '-Wl,--enable-new-dtags,-R/foo')
 
-
         # non-GCC GNULD
         sys.platform = 'bar'
         def gcv(v):
@@ -115,6 +115,38 @@ class UnixCCompilerTestCase(unittest.TestCase):
         sysconfig.get_config_var = gcv
         self.assertEqual(self.cc.rpath_foo(), '-R/foo')
 
+    @unittest.skipUnless(sys.platform == 'darwin', 'test only relevant for OS X')
+    def test_osx_cc_overrides_ldshared(self):
+        # Issue #18080:
+        # ensure that setting CC env variable also changes default linker
+        def gcv(v):
+            if v == 'LDSHARED':
+                return 'gcc-4.2 -bundle -undefined dynamic_lookup '
+            return 'gcc-4.2'
+        sysconfig.get_config_var = gcv
+        with EnvironmentVarGuard() as env:
+            env['CC'] = 'my_cc'
+            del env['LDSHARED']
+            sysconfig.customize_compiler(self.cc)
+        self.assertEqual(self.cc.linker_so[0], 'my_cc')
+
+    @unittest.skipUnless(sys.platform == 'darwin', 'test only relevant for OS X')
+    def test_osx_explict_ldshared(self):
+        # Issue #18080:
+        # ensure that setting CC env variable does not change
+        #   explicit LDSHARED setting for linker
+        def gcv(v):
+            if v == 'LDSHARED':
+                return 'gcc-4.2 -bundle -undefined dynamic_lookup '
+            return 'gcc-4.2'
+        sysconfig.get_config_var = gcv
+        with EnvironmentVarGuard() as env:
+            env['CC'] = 'my_cc'
+            env['LDSHARED'] = 'my_ld -bundle -dynamic'
+            sysconfig.customize_compiler(self.cc)
+        self.assertEqual(self.cc.linker_so[0], 'my_ld')
+
+
 def test_suite():
     return unittest.makeSuite(UnixCCompilerTestCase)
 

Misc/NEWS

@@ -308,6 +308,11 @@ Library
 - Issue #17032: The "global" in the "NameError: global name 'x' is not defined"
   error message has been removed.  Patch by Ram Rachum.
 
+- Issue #18080: When building a C extension module on OS X, if the compiler
+  is overriden with the CC environment variable, use the new compiler as
+  the default for linking if LDSHARED is not also overriden.  This restores
+  Distutils behavior introduced in 3.2.3 and inadvertently dropped in 3.3.0.
+
 Tests
 -----