Adapted for upcoming changes in PyPy's SOABI tag (#373)

docs/news.rst

@@ -7,6 +7,10 @@ Release Notes
 - Updated vendored ``packaging`` library to v20.7
 - Switched to always using LF as line separator when generating ``WHEEL`` files
   (on Windows, CRLF was being used instead)
+- The ABI tag is taken from  the sysconfig SOABI value. On PyPy the SOABI value
+  is ``pypy37-pp73`` which is not compliant with PEP 3149, as it should have
+  both the API tag and the platform tag. This change future-proofs any change
+  in PyPy's SOABI tag to make sure only the ABI tag is used by wheel.
 
 **0.35.1 (2020-08-14)**
 

src/wheel/bdist_wheel.py

@@ -97,6 +97,10 @@ def get_abi_tag():
         abi = '%s%s%s%s%s' % (impl, tags.interpreter_version(), d, m, u)
     elif soabi and soabi.startswith('cpython-'):
         abi = 'cp' + soabi.split('-')[1]
+    elif soabi and soabi.startswith('pypy-'):
+        # we want something like pypy36-pp73
+        abi = '-'.join(soabi.split('-')[:2])
+        abi = abi.replace('.', '_').replace('-', '_')
     elif soabi:
         abi = soabi.replace('.', '_').replace('-', '_')
     else: