read and verify the version

2 files changed, 79 insertions, 21 deletions

diff --git a/findFilename.go b/findFilename.go
index 85ccbf4..5e81974 100644
--- a/findFilename.go
+++ b/findFilename.go
@@ -14,6 +14,39 @@ var ErrProtoVarNotString error = errors.New("name exists but is not a string")
 // Gemini AI can help author some pretty good protobuf code.
 // I never remember the syntax for 'reflect' on these things.
 
+// sets "Filename" if it exists in the protobuf
+func SetFilename(pb proto.Message, filename string) (bool, error) {
+	msg := pb.ProtoReflect() // This is the entry point to the reflection API.
+
+	descriptor := msg.Descriptor() // Get the message's descriptor, which contains metadata about its fields.
+
+	fieldName := protoreflect.Name("Filename")
+	fieldDescriptor := descriptor.Fields().ByName(fieldName)
+
+	if fieldDescriptor == nil {
+		fieldName = protoreflect.Name("filename")
+		fieldDescriptor = descriptor.Fields().ByName(fieldName)
+	}
+
+	if fieldDescriptor == nil {
+		return false, fmt.Errorf("fieldDescriptor == nil")
+	}
+
+	if fieldDescriptor.Kind() != protoreflect.StringKind {
+		// The field exists but is not a string, so we can't return it as one.
+		return false, fmt.Errorf("The field exists but is not a string")
+	}
+
+	valueToSet := protoreflect.ValueOfString(filename)
+
+	// 6. If the field exists and is a string, get its value.
+	// The value is returned as a protoreflect.Value.
+	msg.Set(fieldDescriptor, valueToSet)
+
+	// 7. Convert the protoreflect.Value to a native Go string.
+	return true, nil
+}
+
 // this will try both "filename" and "Filename"
 func GetFilename(pb proto.Message) (string, error) {
 	// 1. Get the protoreflect.Message interface from the message.
@@ -56,35 +89,35 @@ func GetFilename(pb proto.Message) (string, error) {
 	return value.String(), nil
 }
 
-// sets "Filename" if it exists in the protobuf
-func SetFilename(pb proto.Message, filename string) (bool, error) {
-	msg := pb.ProtoReflect() // This is the entry point to the reflection API.
+// this will try both "filename" and "Filename"
+func GetString(pb proto.Message, varname string) (string, error) {
+	// 1. Get the protoreflect.Message interface from the message.
+	// This is the entry point to the reflection API.
+	msg := pb.ProtoReflect()
 
-	descriptor := msg.Descriptor() // Get the message's descriptor, which contains metadata about its fields.
+	// 2. Get the message's descriptor, which contains metadata about its fields.
+	descriptor := msg.Descriptor()
 
-	fieldName := protoreflect.Name("Filename")
+	// 3. Find the specific field descriptor by its protobuf name ("Filename").
+	// Note: The field name must match the name in the .proto file.
+	fieldName := protoreflect.Name(varname)
 	fieldDescriptor := descriptor.Fields().ByName(fieldName)
 
+	// 4. Check if the field was found. If not, return false.
 	if fieldDescriptor == nil {
-		fieldName = protoreflect.Name("filename")
-		fieldDescriptor = descriptor.Fields().ByName(fieldName)
-	}
-
-	if fieldDescriptor == nil {
-		return false, fmt.Errorf("fieldDescriptor == nil")
+		return "", ErrProtoNoVarName
 	}
 
+	// 5. (Optional but recommended) Verify the field is a string type.
 	if fieldDescriptor.Kind() != protoreflect.StringKind {
 		// The field exists but is not a string, so we can't return it as one.
-		return false, fmt.Errorf("The field exists but is not a string")
+		return "", ErrProtoVarNotString
 	}
 
-	valueToSet := protoreflect.ValueOfString(filename)
-
 	// 6. If the field exists and is a string, get its value.
 	// The value is returned as a protoreflect.Value.
-	msg.Set(fieldDescriptor, valueToSet)
+	value := msg.Get(fieldDescriptor)
 
 	// 7. Convert the protoreflect.Value to a native Go string.
-	return true, nil
+	return value.String(), nil
 }
diff --git a/load.go b/load.go
index 93bd19a..dba0bf1 100644
--- a/load.go
+++ b/load.go
@@ -73,19 +73,44 @@ func ConfigLoad(pb proto.Message, argname string, protoname string) error {
 func Load(pb proto.Message) error {
 	fullname, err := GetFilename(pb)
 	if err != nil {
-		log.Info("filename =", fullname, err)
+		log.Info("'Filename' is not in: =", fullname, err)
 		return err
 	}
+	ver, err := GetString(pb, "version")
+	if err != nil {
+		log.Info("'Version' is not in: =", fullname, err)
+		return err
+	}
+	var worked bool
 	if strings.HasSuffix(fullname, ".text") {
-		return loadTEXT(pb, fullname)
+		if err := loadTEXT(pb, fullname); err != nil {
+			return err
+		}
+		worked = true
 	}
 	if strings.HasSuffix(fullname, ".json") {
-		return loadJSON(pb, fullname)
+		if err := loadJSON(pb, fullname); err != nil {
+			return err
+		}
+		worked = true
 	}
 	if strings.HasSuffix(fullname, ".pb") {
-		return loadPB(pb, fullname)
+		if err := loadPB(pb, fullname); err != nil {
+			return err
+		}
+		worked = true
 	}
-	return log.Errorf("unknown filetype %s", fullname)
+	if !worked {
+		return log.Errorf("unknown filetype %s", fullname)
+	}
+	newver, _ := GetString(pb, "version")
+	if ver != newver {
+		log.Printf("VERSION '%s' != '%s'\n", ver, newver)
+		log.Info("Your protobuf file is old and can not be loaded")
+		log.Info("You must delete or convert the file", fullname)
+		panic("protobuf version mismatch")
+	}
+	return nil
 }
 
 func LoadFile(pb proto.Message, fullname string) error {