Determine SAGE_ROOT from sage version and python version

src/pkgs/sage_conf-pypi/setup.py

@@ -13,34 +13,53 @@ class build_py(distutils_build_py):
 
     def run(self):
         DOT_SAGE = os.environ.get('DOT_SAGE', os.path.join(os.environ.get('HOME'), '.sage'))
-        # config.status and other configure output has to be writable.
-        SAGE_ROOT = os.path.join(DOT_SAGE, 'sage-{}-{}'.format(self.distribution.version,
-                                                               sysconfig.get_config_var('SOABI')))
+        HERE = os.path.dirname(__file__)
+        with open(os.path.join(HERE, 'VERSION.txt')) as f:
+            sage_version = f.read().strip()
+        # Until pynac is repackaged as a pip-installable package (#30534), SAGE_LOCAL still has to be specific to
+        # the Python version.  Note that as of pynac-0.7.26.sage-2020-04-03, on Cygwin, pynac is linked through
+        # to libpython; whereas on all other platforms, it is not linked through, so we only key it to the SOABI.
+        soabi = sysconfig.get_config_var('SOABI')
+        if sys.platform == 'cygwin':
+            libdir_tag = sysconfig.get_config_var('LIBDIR').replace(' ', '-').replace('\\', '-').replace('/', '-')
+            ldversion = sysconfig.get_config_var('LDVERSION')
+            python_tag = f'{libdir_tag}-{ldversion}'
+        else:
+            python_tag = soabi
+        # TODO: These two should be user-configurable with options passed to "setup.py install"
+        SAGE_ROOT = os.path.join(DOT_SAGE, f'sage-{sage_version}-{python_tag}')
         SAGE_LOCAL = os.path.join(SAGE_ROOT, 'local')
         if os.path.exists(os.path.join(SAGE_ROOT, 'config.status')):
-            print('Reusing {}'.format(SAGE_ROOT))
+            print('Reusing SAGE_ROOT={SAGE_ROOT}')
         else:
+            # config.status and other configure output has to be writable.
+            # So (until the Sage distribution supports VPATH builds - #21469), we have to make a copy of sage_root.
             try:
                 shutil.copytree('sage_root', SAGE_ROOT)  # will fail if already exists
             except Exception:
-                raise DistutilsSetupError("the directory SAGE_ROOT={} already exists but it is not configured.  Please remove it and try again.".format(SAGE_ROOT))
-            cmd = "cd {} && ./configure --prefix={} --with-python={} --with-system-python3=force".format(SAGE_ROOT, SAGE_LOCAL, sys.executable)
-            print("Running {}".format(cmd))
+                raise DistutilsSetupError(f"the directory SAGE_ROOT={SAGE_ROOT} already exists but it is not configured.  Please remove it and try again.")
+            cmd = f"cd {SAGE_ROOT} && ./configure --prefix={SAGE_LOCAL} --with-python={sys.executable} --with-system-python3=force"
+            print(f"Running {cmd}")
             if os.system(cmd) != 0:
                 raise DistutilsSetupError("configure failed")
 
-        cmd = "cd {} && make V=0 build-local".format(SAGE_ROOT)
+        # build-local only builds the non-Python packages of the Sage distribution.
+        # It still makes an (empty) venv in SAGE_LOCAL, which is unused by default;
+        # but a user could use "make build-venv" to build compatible wheels for all Python packages.
+        # TODO: A target to only build wheels of tricky packages
+        # (that use native libraries shared with other packages).
+        cmd = f"cd {SAGE_ROOT} && make V=0 build-local"
         if os.system(cmd) != 0:
             raise DistutilsSetupError("make build-local failed")
 
         # Install configuration
         shutil.copyfile(os.path.join(SAGE_ROOT, 'build', 'pkgs', 'sage_conf', 'src', 'sage_conf.py'),
-                        'sage_conf.py')
+                        os.path.join(HERE, 'sage_conf.py'))
         if not self.distribution.py_modules:
             self.py_modules = self.distribution.py_modules = []
         self.distribution.py_modules.append('sage_conf')
         shutil.copyfile(os.path.join(SAGE_ROOT, 'src', 'bin', 'sage-env-config'),
-                        os.path.join('bin', 'sage-env-config'))
+                        os.path.join(HERE, 'bin', 'sage-env-config'))
         distutils_build_py.run(self)
 
 class build_scripts(distutils_build_scripts):