pes_events_scanner: override repositories when applying an event

The Package class has custom __hash__ and __eq__ methods in order to
achieve a straightforward presentation via set manipulation. However,
this causes problems, e.g., when applying split events. For example:
Applying the event Split(in={(A, repo1)}, out={(A, repo2), (B, repo2)})
to the package state {(A, repo1), (B, repo1)} results in the following:
  {(A, repo1), (B, repo1)} --apply--> {(A, repo2), (B, repo1)}
which is undesired as repo1 is a source system repository. Such
a package will get reported to the user as potentially removed during
the upgrade. This patch addresses this unwanted behavior.

repos/system_upgrade/common/actors/peseventsscanner/libraries/pes_events_scanner.py

@@ -139,8 +139,9 @@ def compute_pkg_changes_between_consequent_releases(source_installed_pkgs,
         if event.action == Action.PRESENT:
             for pkg in event.in_pkgs:
                 if pkg in seen_pkgs:
+                    # Remove the package with the old repository, add the one with the new one. The Package class has
+                    # a custom __hash__ and __eq__ comparing only name and modulestream - pkg.repository is ignored.
                     if pkg in target_pkgs:
-                        # Remove the package with the old repository, add the one with the new one
                         target_pkgs.remove(pkg)
                     target_pkgs.add(pkg)
         elif event.action == Action.DEPRECATED:
@@ -163,7 +164,10 @@ def compute_pkg_changes_between_consequent_releases(source_installed_pkgs,
                              event.id, event.action, removed_pkgs_str, added_pkgs_str)
 
                 # In pkgs are present, event can be applied
+                # Note: We do a .difference(event.out_packages) followed by an .union(event.out_packages) to overwrite
+                # #     repositories of the packages (Package has overwritten __hash__ and __eq__)
                 target_pkgs = target_pkgs.difference(event.in_pkgs)
+                target_pkgs = target_pkgs.difference(event.out_pkgs)
                 target_pkgs = target_pkgs.union(event.out_pkgs)
 
         pkgs_to_demodularize = pkgs_to_demodularize.difference(event.in_pkgs)