fix: make ConfigCompatError.Error more robust and add UT

Author: NathanBSC

params/config.go

@@ -891,9 +891,11 @@ func (err *ConfigCompatError) Error() string {
 		return fmt.Sprintf("mismatching %s in database (have block %d, want block %d, rewindto block %d)", err.What, err.StoredBlock, err.NewBlock, err.RewindToBlock)
 	}
 
-	if err.StoredTime == nil {
+	if err.StoredTime == nil && err.NewTime == nil {
+		return ""
+	} else if err.StoredTime == nil && err.NewTime != nil {
 		return fmt.Sprintf("mismatching %s in database (have timestamp nil, want timestamp %d, rewindto timestamp %d)", err.What, *err.NewTime, err.RewindToTime)
-	} else if err.NewTime == nil {
+	} else if err.StoredTime != nil && err.NewTime == nil {
 		return fmt.Sprintf("mismatching %s in database (have timestamp %d, want timestamp nil, rewindto timestamp %d)", err.What, *err.StoredTime, err.RewindToTime)
 	}
 	return fmt.Sprintf("mismatching %s in database (have timestamp %d, want timestamp %d, rewindto timestamp %d)", err.What, *err.StoredTime, *err.NewTime, err.RewindToTime)

params/config_test.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/stretchr/testify/require"
 )
 
 func TestCheckCompatible(t *testing.T) {
@@ -137,3 +138,20 @@ func TestConfigRules(t *testing.T) {
 		t.Errorf("expected %v to be shanghai", stamp)
 	}
 }
+
+func TestTimestampCompatError(t *testing.T) {
+	require.Equal(t, new(ConfigCompatError).Error(), "")
+
+	errWhat := "Shanghai fork timestamp"
+	require.Equal(t, newTimestampCompatError(errWhat, nil, newUint64(1681338455)).Error(),
+		"mismatching Shanghai fork timestamp in database (have timestamp nil, want timestamp 1681338455, rewindto timestamp 1681338454)")
+
+	require.Equal(t, newTimestampCompatError(errWhat, newUint64(1681338455), nil).Error(),
+		"mismatching Shanghai fork timestamp in database (have timestamp 1681338455, want timestamp nil, rewindto timestamp 1681338454)")
+
+	require.Equal(t, newTimestampCompatError(errWhat, newUint64(1681338455), newUint64(600624000)).Error(),
+		"mismatching Shanghai fork timestamp in database (have timestamp 1681338455, want timestamp 600624000, rewindto timestamp 600623999)")
+
+	require.Equal(t, newTimestampCompatError(errWhat, newUint64(0), newUint64(1681338455)).Error(),
+		"mismatching Shanghai fork timestamp in database (have timestamp 0, want timestamp 1681338455, rewindto timestamp 0)")
+}