commit 56766151d170674366076bf32b9c4f670021e7c0
Author: James Antill <james@and.org>
Date:   Fri Aug 28 10:46:52 2009 -0400

     Don't accidentally exit 1, when someone asks to update a non-existant pkg
    
     This got introduced in ef6f313d5f97aa7398ac3aa04c4637d8b9da7125 from
    April, 2009. It's not indended behaviour.

diff --git a/yum/__init__.py b/yum/__init__.py
index 3f75528..faa4895 100644
--- a/yum/__init__.py
+++ b/yum/__init__.py
@@ -2944,7 +2944,11 @@ class YumBase(depsolve.Depsolve):
             #  Always look for available packages, it doesn't seem to do any
             # harm (apart from some time). And it fixes weird edge cases where
             # "update a" (which requires a new b) is different from "update b"
-            m =self.pkgSack.returnNewestByNameArch(patterns=[kwargs['pattern']])
+            try:
+                pats = [kwargs['pattern']]
+                m = self.pkgSack.returnNewestByNameArch(patterns=pats)
+            except Errors.PackageSackError:
+                m = []
             availpkgs.extend(m)
 
             if not availpkgs and not instpkgs: