[gentoo-portage-dev] [PATCH] dep_zapdeps: make package selections internally consistent (bug 600346)

[Zac Medico]

When selecting packages to determine which choices have upgrades
or downgrades relative to other choices, make the package selections
internally consistent by choosing a package that satisfies all atoms
in the choice which match a package in the same slot.

Also, fix the Atom.match() method to handle _pkg_str instances,
since dep_zapdeps can pass in _pkg_str instances instead of Package
instances.

X-Gentoo-Bug: 600346
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=600346
---
 pym/portage/dep/__init__.py  | 16 ++++++++++++----
 pym/portage/dep/dep_check.py | 19 +++++++++++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/pym/portage/dep/__init__.py b/pym/portage/dep/__init__.py
index 5dd1638..968ff5b 100644
--- a/pym/portage/dep/__init__.py
+++ b/pym/portage/dep/__init__.py
@@ -1603,10 +1603,18 @@ class Atom(_unicode):
 		if pkg.cp == self.cp:
 			return bool(match_from_list(self, [pkg]))
 		else:
-			for provided_cp in pkg.provided_cps:
-				if provided_cp == self.cp:
-					return bool(match_from_list(
-						self.replace(self.cp, provided_cp, 1), [pkg]))
+			try:
+				provided_cps = pkg.provided_cps
+			except AttributeError:
+				# Since _pkg_str instances lack PROVIDE metadata,
+				# just ignore this case (PROVIDE has been deprecated
+				# for years).
+				pass
+			else:
+				for provided_cp in provided_cps:
+					if provided_cp == self.cp:
+						return bool(match_from_list(
+							self.replace(self.cp, provided_cp, 1), [pkg]))
 		return False
 
 _extended_cp_re_cache = {}
diff --git a/pym/portage/dep/dep_check.py b/pym/portage/dep/dep_check.py
index 9d2ca4b..d2a8800 100644
--- a/pym/portage/dep/dep_check.py
+++ b/pym/portage/dep/dep_check.py
@@ -5,6 +5,7 @@ from __future__ import unicode_literals
 
 __all__ = ['dep_check', 'dep_eval', 'dep_wordreduce', 'dep_zapdeps']
 
+import collections
 import logging
 import operator
 
@@ -354,6 +355,7 @@ def dep_zapdeps(unreduced, reduced, myroot, use_binaries=0, trees=None):
 		all_use_satisfied = True
 		all_use_unmasked = True
 		conflict_downgrade = False
+		slot_atoms = collections.defaultdict(list)
 		slot_map = {}
 		cp_map = {}
 		for atom in atoms:
@@ -418,9 +420,26 @@ def dep_zapdeps(unreduced, reduced, myroot, use_binaries=0, trees=None):
 					avail_slot = Atom("%s:%s" % (atom.cp, avail_pkg.slot))
 
 			slot_map[avail_slot] = avail_pkg
+			slot_atoms[avail_slot].append(atom)
 			highest_cpv = cp_map.get(avail_pkg.cp)
 			if highest_cpv is None or \
 				vercmp(avail_pkg.version, highest_cpv.version) > 0:
+				if (highest_cpv is not None and
+					highest_cpv.slot == avail_pkg.slot):
+					# If possible, make the package selection internally
+					# consistent by choosing a package that satisfies all
+					# atoms which match a package in the same slot. Later on,
+					# the package version chosen here is used in the
+					# has_upgrade/has_downgrade logic to prefer choices with
+					# upgrades, and a package choice that is not internally
+					# consistent will lead the has_upgrade/has_downgrade logic
+					# to produce invalid results (see bug 600346).
+					all_match_current = all(a.match(avail_pkg)
+						for a in slot_atoms[avail_slot])
+					all_match_previous = all(a.match(highest_cpv)
+						for a in slot_atoms[avail_slot])
+					if all_match_previous and not all_match_current:
+						continue
 				cp_map[avail_pkg.cp] = avail_pkg
 
 		this_choice = _dep_choice(atoms=atoms, slot_map=slot_map,
-- 
2.7.4