commit b586ff502946fbd3271db8370cb546f696c51cfd
Author: Michal Domonkos <mdomonko@redhat.com>
Date:   Fri Oct 20 19:47:36 2017 +0200

    verifytree: handle no @core group gracefully. BZ 1349433
    
    It's not clear to me whether @core group is really mandatory, however
    let's make verifytree fail if it's not defined so that we don't change
    the return code to 0 for that case; we would return 1 previously (python
    traceback) and now we OR the BAD_COMPS flag which is 4 (still not 1 but
    at least non-zero).

diff --git a/verifytree.py b/verifytree.py
index 6a127cd..603a633 100755
--- a/verifytree.py
+++ b/verifytree.py
@@ -278,7 +278,14 @@ def main():
     elif not (retval & BAD_COMPS or opts.nocomps):
         print "Checking mandatory @core packages"
         group = my.comps.return_group('core')
-        for pname in group.mandatory_packages:
+        if group is not None:
+            pkgs = group.mandatory_packages
+        else:
+            print "  @core group not found"
+            retval = retval | BAD_COMPS
+            report('COMPS','FAILED')
+            pkgs = []
+        for pname in pkgs:
             # FIXME: this pulls from pkgSack, which (I guess) is populated 
             # based on the arch etc. of the current host.. so you can't check
             # the x86_64 repo from an i386 machine, f'rinstance.