From python3-foo packages automatically generate python3.X-foo Obsoletes tags on CentOS/RHEL

pythonname.attr

@@ -16,4 +16,27 @@
     end
 }
 
+%__pythonname_obsoletes() %{?rhel:%{lua:
+    -- On CentOS/RHEL we automatically generate Obsoletes tags in the form:
+    --   package python3-foo -> Obsoletes: python3.XY-foo
+    -- This provides a clean upgrade path between major versions of CentOS/RHEL.
+    -- In Fedora this is not needed as we don't ship ecosystem packages
+    -- for alternative Python interpreters.
+    local python = require 'fedora.srpm.python'
+    -- this macro is called for each file in a package, the path being in %1
+    -- but we don't need to know the path, so we would get for each file: Macro %1 defined but not used within scope
+    -- in here, we expand %name conditionally on %1 to suppress the warning
+    local name = rpm.expand('%{?1:%{name}}')
+    local evr = rpm.expand('%{?epoch:%{epoch}:}%{version}-%{release}')
+    local obsoletes = python.python_altobsoletes_once(name, evr)
+    -- obsoletes is either an array/table or nil
+    -- nil means the function was already called with the same arguments:
+    --   either with another file in %1 or manually via %py_provides
+    if obsoletes then
+      for i, obsolete in ipairs(obsoletes) do
+          print(obsolete .. ' ')
+        end
+    end
+}}
+
 %__pythonname_path ^/