fixes #1285

backend/protos/xyz/block/ftl/v1/schema/schema.proto

@@ -79,9 +79,16 @@ message EnumVariant {
 }
 
 message Error {
+  enum ErrorLevel {
+    INFO = 0;
+    WARN = 1;
+    ERROR = 2;
+  }
+
   string msg = 1;
   Position pos = 2;
   int64 endColumn = 3;
+  ErrorLevel level = 4;
 }
 
 message ErrorList {

backend/schema/errors.go

@@ -8,10 +8,19 @@ import (
 	schemapb "github.com/TBD54566975/ftl/backend/protos/xyz/block/ftl/v1/schema"
 )
 
+type ErrorLevel int
+
+const (
+	INFO ErrorLevel = iota
+	WARN
+	ERROR
+)
+
 type Error struct {
-	Msg       string   `json:"msg" protobuf:"1"`
-	Pos       Position `json:"pos" protobuf:"2"`
-	EndColumn int      `json:"endCol" protobuf:"3"`
+	Msg       string     `json:"msg" protobuf:"1"`
+	Pos       Position   `json:"pos" protobuf:"2"`
+	EndColumn int        `json:"endCol" protobuf:"3"`
+	Level     ErrorLevel `json:"level" protobuf:"4"`
 }
 
 func (e Error) ToProto() *schemapb.Error {
@@ -67,11 +76,23 @@ func ErrorListFromProto(e *schemapb.ErrorList) *ErrorList {
 	}
 }
 
-func Errorf(pos Position, endColumn int, format string, args ...any) *Error {
-	err := Error{Msg: fmt.Sprintf(format, args...), Pos: pos, EndColumn: endColumn}
+func makeError(level ErrorLevel, pos Position, endColumn int, format string, args ...any) *Error {
+	err := Error{Msg: fmt.Sprintf(format, args...), Pos: pos, EndColumn: endColumn, Level: level}
 	return &err
 }
 
+func Infof(pos Position, endColumn int, format string, args ...any) *Error {
+	return makeError(INFO, pos, endColumn, format, args...)
+}
+
+func Warnf(pos Position, endColumn int, format string, args ...any) *Error {
+	return makeError(WARN, pos, endColumn, format, args...)
+}
+
+func Errorf(pos Position, endColumn int, format string, args ...any) *Error {
+	return makeError(ERROR, pos, endColumn, format, args...)
+}
+
 func Wrapf(pos Position, endColumn int, err error, format string, args ...any) *Error {
 	if format == "" {
 		format = "%s"

backend/schema/protobuf.go

@@ -86,6 +86,7 @@ func generateStruct(t reflect.Type, messages map[string]string) {
 	if typesWithRuntime[t.Name()] {
 		fmt.Fprintf(w, "\n  optional %sRuntime runtime = 31634;\n", name)
 	}
+	generateWellKnownNestedEnums(t, w)
 	fields := reflect.VisibleFields(t)
 	// Sort by protobuf tag
 	slices.SortFunc(fields, func(a, b reflect.StructField) int {
@@ -132,6 +133,18 @@ func generateStruct(t reflect.Type, messages map[string]string) {
 	messages[t.Name()] = w.String()
 }
 
+// generateWellKnownNestedEnums generates the well-known nested enums for a given reflect.Type.
+// Reflection cannot discover type aliased enums, so they need to get generated manually.
+func generateWellKnownNestedEnums(t reflect.Type, w *strings.Builder) {
+	if (t == reflect.TypeOf(Error{})) {
+		fmt.Fprintf(w, "  enum %s {\n", reflect.TypeOf(ErrorLevel(0)).Name())
+		fmt.Fprintf(w, "    INFO = %d;\n", INFO)
+		fmt.Fprintf(w, "    WARN = %d;\n", WARN)
+		fmt.Fprintf(w, "    ERROR = %d;\n", ERROR)
+		fmt.Fprintf(w, "  }\n")
+	}
+}
+
 func generateUnion(t reflect.Type, messages map[string]string) {
 	t = indirect(t)
 	if _, ok := messages[t.Name()]; ok {
@@ -166,6 +179,10 @@ func generateProtoType(t reflect.Type) string {
 	case reflect.String:
 		return "string"
 	case reflect.Int:
+		// determine if t is a well-known type aliased enum
+		if t == reflect.TypeOf(ErrorLevel(0)) {
+			return t.Name()
+		}
 		return "int64"
 	case reflect.Bool:
 		return "bool"

backend/schema/protobuf_test.go

@@ -14,3 +14,7 @@ func TestProtoRoundtrip(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, Normalise(testSchema), Normalise(actual))
 }
+
+func TestErrorProtoGeneration(t *testing.T) {
+
+}