Filter out cruft in find_smooth_updateable_binaries

When calculating smooth updateable binaries, filter out cruft binaries from
unstable, because they will not be part of the set of packages that britney
will try to migrate to testing.

Signed-off-by: Ivo De Decker <ivodd@debian.org>

britney2/utils.py

@@ -961,11 +961,13 @@ def find_smooth_updateable_binaries(binaries_to_check,
         binary, _, parch = pkg_id
 
         cruft = False
+        cruftbins = set()
 
         # Not a candidate for smooth up date (newer non-cruft version in unstable)
         if binary in binaries_s[parch]:
             if binaries_s[parch][binary].source_version == source_data.version:
                 continue
+            cruftbins.add(binaries_s[parch][binary].pkg_id)
             cruft = True
 
         # Maybe a candidate (cruft or removed binary): check if config allows us to smooth update it.
@@ -987,7 +989,10 @@ def find_smooth_updateable_binaries(binaries_to_check,
                 combined.add(pkg_id)
                 for rdep in rdeps:
                     for dep_clause in pkg_universe.dependencies_of(rdep):
-                        if dep_clause <= combined:
+                        # filter out cruft binaries from unstable, because
+                        # they will not be added to the set of packages that
+                        # will be migrated
+                        if dep_clause - cruftbins <= combined:
                             smooth_update_it = True
                             break