FAB-16483 Improve error message

Because channel creation txes and config update txes use the same
format, explicitly calling out whether the tx is being processed for an
existing channel will help reduce user confusion.

Signed-off-by: Jason Yellick <jyellick@us.ibm.com>
Change-Id: I0843afdb54802dda181ab41e24328a1560bec268

Author: Jason Yellick

orderer/common/msgprocessor/standardchannel.go

@@ -118,14 +118,14 @@ func (s *StandardChannel) ProcessNormalMsg(env *cb.Envelope) (configSeq uint64,
 // return the resulting config message and the configSeq the config was computed from.  If the config impetus message
 // is invalid, an error is returned.
 func (s *StandardChannel) ProcessConfigUpdateMsg(env *cb.Envelope) (config *cb.Envelope, configSeq uint64, err error) {
-	logger.Debugf("Processing config update message for channel %s", s.support.ChannelID())
+	logger.Debugf("Processing config update message for exisitng channel %s", s.support.ChannelID())
 
 	// Call Sequence first.  If seq advances between proposal and acceptance, this is okay, and will cause reprocessing
 	// however, if Sequence is called last, then a success could be falsely attributed to a newer configSeq
 	seq := s.support.Sequence()
 	err = s.filters.Apply(env)
 	if err != nil {
-		return nil, 0, err
+		return nil, 0, errors.WithMessage(err, "config update for existing channel did not pass initial checks")
 	}
 
 	configEnvelope, err := s.support.ProposeConfigUpdate(env)
@@ -145,12 +145,12 @@ func (s *StandardChannel) ProcessConfigUpdateMsg(env *cb.Envelope) (config *cb.E
 	// check is negligible, as this is the reconfig path and not the normal path.
 	err = s.filters.Apply(config)
 	if err != nil {
-		return nil, 0, err
+		return nil, 0, errors.WithMessage(err, "config update for existing channel did not pass final checks")
 	}
 
 	err = s.maintenanceFilter.Apply(config)
 	if err != nil {
-		return nil, 0, err
+		return nil, 0, errors.WithMessage(err, "config update for existing channel did not pass maintenance checks")
 	}
 
 	return config, seq, nil

orderer/common/msgprocessor/systemchannel_test.go

@@ -22,6 +22,7 @@ import (
 	"github.com/hyperledger/fabric/internal/pkg/identity"
 	"github.com/hyperledger/fabric/orderer/common/msgprocessor/mocks"
 	"github.com/hyperledger/fabric/protoutil"
+	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -239,7 +240,7 @@ func TestSystemChannelConfigUpdateMsg(t *testing.T) {
 				},
 			}),
 		})
-		assert.Equal(t, RejectRule.Apply(nil), err)
+		assert.Equal(t, RejectRule.Apply(nil), errors.Cause(err))
 	})
 	t.Run("Good", func(t *testing.T) {
 		mscs := &mockSystemChannelSupport{