python: urls return [None] if not pypi

lib/spack/spack/build_systems/python.py

@@ -354,10 +354,18 @@ def homepage(cls) -> Optional[str]:  # type: ignore[override]
         return None
 
     @lang.classproperty
-    def url(cls) -> Optional[str]:
+    def urls(cls) -> Optional[List[str]]:
         if cls.pypi:
-            return f"https://files.pythonhosted.org/packages/source/{cls.pypi[0]}/{cls.pypi}"
+            urls = [f"https://files.pythonhosted.org/packages/source/{cls.pypi[0]}/{cls.pypi}"]
-        return None
+            assert cls.pypi.count("/") == 1, "PyPI class attribute must include a single slash"
+            name, file = cls.pypi.split("/")
+            name_dash_count = name.count("-")
+            if name_dash_count > 0:
+                # replace all but last dash with underscores for pypi.org listing changes
+                pypi = "/".join([name, file.replace("-", "_", name_dash_count)])
+                urls.append(f"https://files.pythonhosted.org/packages/source/{pypi[0]}/{pypi}")
+            return urls
+        return [None]
 
     @lang.classproperty
     def list_url(cls) -> Optional[str]:  # type: ignore[override]

lib/spack/spack/package_base.py

@@ -2426,9 +2426,8 @@ def all_urls(self) -> List[str]:
         if hasattr(self, "url") and self.url:
             urls.append(self.url)
 
-        # fetch from first entry in urls to save time
         if hasattr(self, "urls") and self.urls:
-            urls.append(self.urls[0])
+            urls.extend(self.urls)
 
         for args in self.versions.values():
             if "url" in args: