Feature #2597 -- fix cycle relationship notification format.

The SimpleGraph class was reporting duplicate data when printing cycles:

    Notify[c]Notify[c] => Notify[d]
    Notify[a]Notify[a] => Notify[b]

This was caused by throwing the array representation of the edge into a
string, rather than just the relationship data; we only care about the later,
so now we only emit that later and have the correct text in the error.

2 files changed, 11 insertions, 3 deletions

diff --git a/lib/puppet/simple_graph.rb b/lib/puppet/simple_graph.rb
index 9d7f218a6..29e46c9bd 100644
--- a/lib/puppet/simple_graph.rb
+++ b/lib/puppet/simple_graph.rb
@@ -109,7 +109,7 @@ class Puppet::SimpleGraph
     # each of its out-edges.
     while v = zeros.pop
       result << v
-      @out_from[v].each { |v2,es| 
+      @out_from[v].each { |v2,es|
         degree[v2].delete(v)
         zeros << v2 if degree[v2].empty?
       }
@@ -117,7 +117,9 @@ class Puppet::SimpleGraph
 
     # If we have any vertices left with non-zero in-degrees, then we've found a cycle.
     if cycles = degree.values.reject { |ns| ns.empty? } and cycles.length > 0
-      message = cycles.collect { |edges| '('+edges.collect { |e| e.to_s }.join(", ")+')' }.join(", ")
+      message = cycles.collect { |edges|
+        '(' + edges.collect { |e| e[1].to_s }.join(", ") + ')'
+      }.join(", ")
       raise Puppet::Error, "Found dependency cycles in the following relationships: #{message}; try using the '--graph' option and open the '.dot' files in OmniGraffle or GraphViz"
     end
 
@@ -141,7 +143,7 @@ class Puppet::SimpleGraph
     # each of its out-edges.
     while v = zeros.pop
       result << v
-      @out_from[v].each { |v2,es| 
+      @out_from[v].each { |v2,es|
         zeros << v2 if (degree[v2] -= 1) == 0
       }
     end
diff --git a/spec/unit/simple_graph_spec.rb b/spec/unit/simple_graph_spec.rb
index e49811ea7..0d1a3b4a7 100755
--- a/spec/unit/simple_graph_spec.rb
+++ b/spec/unit/simple_graph_spec.rb
@@ -303,6 +303,12 @@ describe Puppet::SimpleGraph do
       proc { @graph.topsort }.should_not raise_error
     end
 
+    it "should produce the correct relationship text" do
+      add_edges :a => :b, :b => :a
+      want = %r{following relationships: \(b => a\), \(a => b\)}
+      expect { @graph.topsort }.to raise_error(Puppet::Error, want)
+    end
+
     # Our graph's add_edge method is smart enough not to add
     # duplicate edges, so we use the objects, which it doesn't
     # check.