Add debug output for cases like bug #453400.
diff --git a/pym/_emerge/resolver/slot_collision.py b/pym/_emerge/resolver/slot_collision.py
index f07b01a..f8e1e4e 100644
--- a/pym/_emerge/resolver/slot_collision.py
+++ b/pym/_emerge/resolver/slot_collision.py
@@ -317,6 +317,26 @@
#Use conditionals not met.
violated_atom = atom.violated_conditionals(_pkg_use_enabled(other_pkg), \
other_pkg.iuse.is_valid_flag)
+ if violated_atom.use is None:
+ # Something like bug #453400 caused the
+ # above findAtomForPackage call to
+ # to return None unexpectedly.
+ msg = ("\n\n!!! BUG: Detected "
+ "USE dep match inconsistency:\n"
+ "\tppkg: %s\n"
+ "\tviolated_atom: %s\n"
+ "\tatom: %s unevaluated: %s\n"
+ "\tother_pkg: %s IUSE: %s USE: %s\n" %
+ (ppkg,
+ violated_atom,
+ atom,
+ atom.unevaluated_atom,
+ other_pkg,
+ sorted(other_pkg.iuse.all),
+ sorted(_pkg_use_enabled(other_pkg))))
+ writemsg(msg, noiselevel=-2)
+ raise AssertionError(
+ 'BUG: USE dep match inconsistency')
for flag in violated_atom.use.enabled.union(violated_atom.use.disabled):
atoms = collision_reasons.get(("use", flag), set())
atoms.add((ppkg, atom, other_pkg))
