[gentoo-portage-dev] [PATCH 2/2] depgraph: fix missed llvm update (bug 584626)

[Zac Medico]

Fix check_reverse_dependencies to ignore dependencies of parent packages
for which updates are desirable, and add required  _want_update_pkg
support for DependencyArg parents. This solves a missed llvm update by
ignoring a reverse dependency from the installed instance of clang,
since an update to a newer version of clang is desirable.

In order to cope with this change, there are 2 existing unit tests
that require larger --backtrack settings in order to succeed.

X-Gentoo-Bug: 584626
X-Gentoo-Bug-url: https://bugs.gentoo.org/show_bug.cgi?id=584626
---
 pym/_emerge/depgraph.py                            | 40 ++++++++++++++++++++--
 .../soname/test_slot_conflict_reinstall.py         |  1 +
 .../tests/resolver/test_slot_conflict_rebuild.py   |  2 +-
 .../resolver/test_slot_operator_reverse_deps.py    |  6 +++-
 4 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/pym/_emerge/depgraph.py b/pym/_emerge/depgraph.py
index f78f08d..ef3cc5d 100644
--- a/pym/_emerge/depgraph.py
+++ b/pym/_emerge/depgraph.py
@@ -1822,6 +1822,22 @@ class depgraph(object):
 						# necessarily relevant.
 						continue
 
+					if (not self._frozen_config.excluded_pkgs.
+						findAtomForPackage(parent,
+						modified_use=self._pkg_use_enabled(parent)) and
+						self._upgrade_available(parent)):
+						want_update = False
+						for grandparent in self._dynamic_config.digraph.\
+							parent_nodes(parent):
+							if self._want_update_pkg(grandparent, parent):
+								want_update = True
+								break
+
+						if want_update:
+							# This parent may be irrelevant, since an
+							# update is available (see bug 584626).
+							continue
+
 				atom_set = InternalPackageSet(initial_atoms=(atom,),
 					allow_repo=True)
 				if not atom_set.findAtomForPackage(candidate_pkg,
@@ -2113,6 +2129,19 @@ class depgraph(object):
 
 		self._dynamic_config._need_restart = True
 
+	def _upgrade_available(self, pkg):
+		"""
+		Detect cases where an upgrade of the given package is available
+		within the same slot.
+		"""
+		available_pkg = None
+		for available_pkg in self._iter_similar_available(pkg,
+			pkg.slot_atom):
+			if available_pkg >= pkg:
+				return True
+
+		return False
+
 	def _downgrade_probe(self, pkg):
 		"""
 		Detect cases where a downgrade of the given package is considered
@@ -5382,9 +5411,14 @@ class depgraph(object):
 				# should have been masked before it was selected
 				raise
 
-		depth = parent.depth or 0
-		if isinstance(depth, int):
-			depth += 1
+		if isinstance(parent, Package):
+			depth = parent.depth or 0
+			if isinstance(depth, int):
+				depth += 1
+		elif parent.reset_depth:
+			depth = 0
+		else:
+			depth = self._UNREACHABLE_DEPTH
 
 		if arg_atoms:
 			for arg, atom in arg_atoms:
diff --git a/pym/portage/tests/resolver/soname/test_slot_conflict_reinstall.py b/pym/portage/tests/resolver/soname/test_slot_conflict_reinstall.py
index 40e6995..f474761 100644
--- a/pym/portage/tests/resolver/soname/test_slot_conflict_reinstall.py
+++ b/pym/portage/tests/resolver/soname/test_slot_conflict_reinstall.py
@@ -89,6 +89,7 @@ class SonameSlotConflictReinstallTestCase(TestCase):
 					"--ignore-soname-deps": "n",
 					"--update": True,
 					"--usepkgonly": True,
+					"--backtrack": 10,
 				},
 				success = True,
 				mergelist = [
diff --git a/pym/portage/tests/resolver/test_slot_conflict_rebuild.py b/pym/portage/tests/resolver/test_slot_conflict_rebuild.py
index b39eaf0..2dfa79c 100644
--- a/pym/portage/tests/resolver/test_slot_conflict_rebuild.py
+++ b/pym/portage/tests/resolver/test_slot_conflict_rebuild.py
@@ -91,7 +91,7 @@ class SlotConflictRebuildTestCase(TestCase):
 			# upgrade and we don't want to trigger unnecessary rebuilds.
 			ResolverPlaygroundTestCase(
 				["@world"],
-				options = {"--update": True, "--deep": True},
+				options = {"--update": True, "--deep": True, "--backtrack": 4},
 				success = True,
 				mergelist = ["app-misc/D-2", "app-misc/E-0"]),
 
diff --git a/pym/portage/tests/resolver/test_slot_operator_reverse_deps.py b/pym/portage/tests/resolver/test_slot_operator_reverse_deps.py
index 72879f8..ce614a4 100644
--- a/pym/portage/tests/resolver/test_slot_operator_reverse_deps.py
+++ b/pym/portage/tests/resolver/test_slot_operator_reverse_deps.py
@@ -79,7 +79,11 @@ class SlotOperatorReverseDepsTestCase(TestCase):
 				["@world"],
 				options = {"--update": True, "--deep": True},
 				success = True,
-				mergelist = [],
+				mergelist = [
+					'sys-devel/llvm-3.8.0-r2',
+					'sys-devel/clang-3.8.0-r100',
+					'media-libs/mesa-11.2.2',
+				],
 			),
 
 			ResolverPlaygroundTestCase(
-- 
2.7.4