topology: enumerate the digest coverage test from the message

The list of fields was written out by hand, so a field added to
VolumeInformationMessage later would fall outside the digest while the test
went on passing, and a change to it would never reach the master. Walk the
message descriptor instead.

Some fields are narrowed or normalised on the way into VolumeInfo, so the
smallest change to the wire value can land back on the stored one; the test
offers several values per field and asks only that some change is visible.

weed/topology/volume_digest_test.go

@@ -3,6 +3,9 @@ package topology
 import (
 	"testing"
 
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/reflect/protoreflect"
+
 	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
 	"github.com/seaweedfs/seaweedfs/weed/stats"
 	"github.com/seaweedfs/seaweedfs/weed/storage"
@@ -68,46 +71,63 @@ func TestVolumeDigestIsIndependentOfReportOrder(t *testing.T) {
 	}
 }
 
+// Every field of VolumeInformationMessage has to reach the digest: one the hash
+// skips is a change the master would never be told about. Enumerated from the
+// message rather than listed here, so a field added later cannot quietly fall
+// outside the digest while this still passes.
 func TestVolumeDigestTracksEveryReportedField(t *testing.T) {
 	base := digestTestVolume(1)
-	mutations := map[string]func(*master_pb.VolumeInformationMessage){
-		"Id":                func(m *master_pb.VolumeInformationMessage) { m.Id = 2 },
-		"Size":              func(m *master_pb.VolumeInformationMessage) { m.Size++ },
-		"Collection":        func(m *master_pb.VolumeInformationMessage) { m.Collection = "other" },
-		"FileCount":         func(m *master_pb.VolumeInformationMessage) { m.FileCount++ },
-		"DeleteCount":       func(m *master_pb.VolumeInformationMessage) { m.DeleteCount++ },
-		"DeletedByteCount":  func(m *master_pb.VolumeInformationMessage) { m.DeletedByteCount++ },
-		"ReadOnly":          func(m *master_pb.VolumeInformationMessage) { m.ReadOnly = true },
-		"ReplicaPlacement":  func(m *master_pb.VolumeInformationMessage) { m.ReplicaPlacement = 10 },
-		"Version":           func(m *master_pb.VolumeInformationMessage) { m.Version = 2 },
-		"Ttl":               func(m *master_pb.VolumeInformationMessage) { m.Ttl = 3 << 8 },
-		"CompactRevision":   func(m *master_pb.VolumeInformationMessage) { m.CompactRevision++ },
-		"ModifiedAtSecond":  func(m *master_pb.VolumeInformationMessage) { m.ModifiedAtSecond++ },
-		"RemoteStorageName": func(m *master_pb.VolumeInformationMessage) { m.RemoteStorageName = "s3" },
-		"RemoteStorageKey":  func(m *master_pb.VolumeInformationMessage) { m.RemoteStorageKey = "k" },
-		"DiskType":          func(m *master_pb.VolumeInformationMessage) { m.DiskType = "ssd" },
-		"DiskId":            func(m *master_pb.VolumeInformationMessage) { m.DiskId = 1 },
-	}
-
 	baseInfo, err := storage.NewVolumeInfo(base)
 	if err != nil {
 		t.Fatal(err)
 	}
-	for name, mutate := range mutations {
-		t.Run(name, func(t *testing.T) {
-			changed := digestTestVolume(1)
-			mutate(changed)
-			changedInfo, err := storage.NewVolumeInfo(changed)
-			if err != nil {
-				t.Fatal(err)
-			}
-			if baseInfo.ReportHash() == changedInfo.ReportHash() {
-				t.Errorf("a change to %s is invisible to the digest, so the master would never be told about it", name)
+
+	fields := base.ProtoReflect().Descriptor().Fields()
+	for i := 0; i < fields.Len(); i++ {
+		fd := fields.Get(i)
+		t.Run(string(fd.Name()), func(t *testing.T) {
+			candidates := distinctValuesFor(t, fd, base.ProtoReflect().Get(fd))
+			for _, candidate := range candidates {
+				changed := proto.Clone(base).(*master_pb.VolumeInformationMessage)
+				changed.ProtoReflect().Set(fd, candidate)
+				changedInfo, err := storage.NewVolumeInfo(changed)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if baseInfo.ReportHash() != changedInfo.ReportHash() {
+					return
+				}
 			}
+			t.Errorf("no change to %s moves the digest, so the master would never be told about one", fd.Name())
 		})
 	}
 }
 
+// distinctValuesFor offers values that differ from current. Several, because
+// some fields are narrowed or normalised on the way into VolumeInfo and the
+// smallest change to the wire value can land back on the stored one.
+func distinctValuesFor(t *testing.T, fd protoreflect.FieldDescriptor, current protoreflect.Value) []protoreflect.Value {
+	t.Helper()
+	switch fd.Kind() {
+	case protoreflect.BoolKind:
+		return []protoreflect.Value{protoreflect.ValueOfBool(!current.Bool())}
+	case protoreflect.Uint32Kind:
+		return []protoreflect.Value{
+			protoreflect.ValueOfUint32(uint32(current.Uint()) + 1),
+			protoreflect.ValueOfUint32(uint32(current.Uint()) + 1<<8),
+			protoreflect.ValueOfUint32(uint32(current.Uint()) + 1<<16),
+		}
+	case protoreflect.Uint64Kind:
+		return []protoreflect.Value{protoreflect.ValueOfUint64(current.Uint() + 1)}
+	case protoreflect.Int64Kind:
+		return []protoreflect.Value{protoreflect.ValueOfInt64(current.Int() + 1)}
+	case protoreflect.StringKind:
+		return []protoreflect.Value{protoreflect.ValueOfString(current.String() + "x")}
+	}
+	t.Fatalf("field %s has kind %s, which this test does not know how to vary", fd.Name(), fd.Kind())
+	return nil
+}
+
 func TestVolumeDigestFollowsVolumeChanges(t *testing.T) {
 	topo, dn := digestTestNode(t)
 	volumes := []*master_pb.VolumeInformationMessage{digestTestVolume(1), digestTestVolume(2)}