use abi3 extension if Extension().is_abi3

3 files changed, 36 insertions, 1 deletions

diff --git a/setuptools/command/build_ext.py b/setuptools/command/build_ext.py
index e6db0764..dad28999 100644
--- a/setuptools/command/build_ext.py
+++ b/setuptools/command/build_ext.py
@@ -59,6 +59,14 @@ elif os.name != 'nt':
 
 if_dl = lambda s: s if have_rtld else ''
 
+def get_abi3_suffix():
+    """Return the file extension for an abi3-compliant Extension()"""
+    import imp
+    for suffix, _, _ in (s for s in imp.get_suffixes() if s[2] == imp.C_EXTENSION):
+        if '.abi3' in suffix:   # Unix
+            return suffix
+        elif suffix == '.pyd':  # Windows
+            return suffix
 
 class build_ext(_build_ext):
 
@@ -96,6 +104,11 @@ class build_ext(_build_ext):
         filename = _build_ext.get_ext_filename(self, fullname)
         if fullname in self.ext_map:
             ext = self.ext_map[fullname]
+            if sys.version_info[0] != 2 and getattr(ext, 'is_abi3'):
+                from distutils.sysconfig import get_config_var
+                so_ext = get_config_var('SO')
+                filename = filename[:-len(so_ext)]
+                filename = filename + get_abi3_suffix()
             if isinstance(ext, Library):
                 fn, ext = os.path.splitext(filename)
                 return self.shlib_compiler.library_filename(fn, libtype)
diff --git a/setuptools/extension.py b/setuptools/extension.py
index 5ea72c06..a6cc0915 100644
--- a/setuptools/extension.py
+++ b/setuptools/extension.py
@@ -36,6 +36,10 @@ have_pyrex = _have_cython
 class Extension(_Extension):
     """Extension that uses '.c' files in place of '.pyx' files"""
 
+    def __init__(self, name, sources, is_abi3=False, **kw):
+        self.is_abi3 = is_abi3
+        _Extension.__init__(self, name, sources, **kw)
+
     def _convert_pyx_sources_to_lang(self):
         """
         Replace sources with .pyx extensions to sources with the target
diff --git a/setuptools/tests/test_build_ext.py b/setuptools/tests/test_build_ext.py
index 5168ebf0..e0f2e73b 100644
--- a/setuptools/tests/test_build_ext.py
+++ b/setuptools/tests/test_build_ext.py
@@ -1,8 +1,10 @@
+import sys
 import distutils.command.build_ext as orig
 
+from distutils.sysconfig import get_config_var
 from setuptools.command.build_ext import build_ext
 from setuptools.dist import Distribution
-
+from setuptools.extension import Extension
 
 class TestBuildExt:
 
@@ -18,3 +20,19 @@ class TestBuildExt:
         res = cmd.get_ext_filename('foo')
         wanted = orig.build_ext.get_ext_filename(cmd, 'foo')
         assert res == wanted
+
+    def test_abi3_filename(self):
+        """
+        Filename needs to be loadable by several versions
+        of Python 3 if 'is_abi3' is truthy on Extension()
+        """
+        dist = Distribution(dict(ext_modules=[Extension('spam.eggs', [], is_abi3=True)]))
+        cmd = build_ext(dist)
+        res = cmd.get_ext_filename('spam.eggs')
+
+        if sys.version_info[0] == 2:
+            assert res.endswith(get_config_var('SO'))
+        elif sys.platform == 'win32':
+            assert res.endswith('eggs.pyd')
+        else:
+            assert 'abi3' in res
\ No newline at end of file