[FAB-2699] ConfigGroup mod policy resolve error

https://jira.hyperledger.org/browse/FAB-2699

The ConfigGroup mod policy is currently resolved like the ConfigValue
and ConfigPolicy mod policies.  For ConfigValue and ConfigPolicy mod
policies, they look for the policy manager managing their config path.

However, ConfigGroups represents nodes in the config path, and therefore
they must resolve their policy manager by looking at their config path
plus their key value.

For example, the group /Channel/Orderer should resolve a mod policy of
Admins to /Channel/Orderer/Admins but it currently resolves it to
/Channel/Admins.

While on the other hand the value /Channel/Orderer/foo should resolve a
mod policy of Admins to /Channel/Orderer/Admins and not
/Channel/Orderer/foo/Admins (because foo is not a group node in the
config).

This CR fixes this mistake, enhances logging slightly, and adds a test
case.

Change-Id: I0d8b58f8ca21f78a8a2d7331e330fea4768ab973
Signed-off-by: Jason Yellick <jyellick@us.ibm.com>

common/config/standardvalues.go

@@ -53,7 +53,7 @@ func NewStandardValues(protosStructs ...interface{}) (*standardValues, error) {
 func (sv *standardValues) Deserialize(key string, value []byte) (proto.Message, error) {
 	msg, ok := sv.lookup[key]
 	if !ok {
-		return nil, fmt.Errorf("Not found")
+		return nil, fmt.Errorf("Unexpected key %s", key)
 	}
 
 	err := proto.Unmarshal(value, msg)

common/configtx/config.go

@@ -210,7 +210,7 @@ func proposeGroup(result *configResult) error {
 		msg, err := valueDeserializer.Deserialize(key, value.Value)
 		if err != nil {
 			result.rollback()
-			return err
+			return fmt.Errorf("Error deserializing key %s for group %s: %s", key, result.groupName, err)
 		}
 		result.deserializedValues[key] = msg
 	}

common/configtx/update.go

@@ -145,6 +145,14 @@ func (cm *configManager) policyForItem(item comparable) (policies.Policy, bool)
 	if !ok {
 		return nil, ok
 	}
+
+	// In the case of the group type, its key is part of its path for the purposes of finding the policy manager
+	if item.ConfigGroup != nil {
+		manager, ok = manager.Manager([]string{item.key})
+	}
+	if !ok {
+		return nil, ok
+	}
 	return manager.GetPolicy(item.modPolicy())
 }
 

common/configtx/update_test.go

@@ -165,4 +165,14 @@ func TestPolicyForItem(t *testing.T) {
 	})
 	assert.True(t, ok)
 	assert.Equal(t, policy, fooPolicy, "Should not have found relative foo policy the foo manager")
+
+	policy, ok = cm.policyForItem(comparable{
+		key:  "foo",
+		path: []string{"root"},
+		ConfigGroup: &cb.ConfigGroup{
+			ModPolicy: "foo",
+		},
+	})
+	assert.True(t, ok)
+	assert.Equal(t, policy, fooPolicy, "Should have found relative foo policy for foo group")
 }