gentypes: option to force generate optional types

Closes #TNTP-3734.

Author: bigbes

README.md

@@ -70,6 +70,7 @@ Flags:
  • `-ext-code`: MessagePack extension code to use for custom types (must be between
    -128 and 127, no default value)
  • `-verbose`: Enable verbose output (default: `false`)
+ • `-force`: Ignore absence of marshal/unmarshal methods on type (default: `false`)
 
 #### Using Generated Types
 

cmd/gentypes/generate.go

@@ -1,2 +1,3 @@
 //go:generate go run github.com/tarantool/go-option/cmd/gentypes -ext-code 1 -package test FullMsgpackExtType
+//go:generate go run github.com/tarantool/go-option/cmd/gentypes -ext-code 2 -force -package test HiddenTypeAlias
 package main

cmd/gentypes/main.go

@@ -27,6 +27,7 @@ var (
 	packagePath string
 	extCode     int
 	verbose     bool
+	force       bool
 )
 
 func logfuncf(format string, args ...interface{}) {
@@ -106,6 +107,7 @@ func main() { //nolint:funlen
 	flag.StringVar(&packagePath, "package", "./", "input and output path")
 	flag.IntVar(&extCode, "ext-code", undefinedExtCode, "extension code")
 	flag.BoolVar(&verbose, "verbose", false, "print verbose output")
+	flag.BoolVar(&force, "force", false, "generate files even if methods do not exist")
 
 	flag.Parse()
 
@@ -171,7 +173,10 @@ func main() { //nolint:funlen
 
 	fmt.Println("generating optional for:", typeName)
 
-	if !typeSpecDef.HasMethod("MarshalMsgpack") || !typeSpecDef.HasMethod("UnmarshalMsgpack") {
+	switch {
+	case force:
+		// Skipping check for MarshalMsgpack and UnmarshalMsgpack methods.
+	case !typeSpecDef.HasMethod("MarshalMsgpack") || !typeSpecDef.HasMethod("UnmarshalMsgpack"):
 		fmt.Println("failed to find MarshalMsgpack or UnmarshalMsgpack method for struct:", typeName)
 		os.Exit(1)
 	}

cmd/gentypes/test/hiddentypealias.go

@@ -0,0 +1,7 @@
+package test
+
+import (
+	"github.com/tarantool/go-option/cmd/gentypes/test/subpackage"
+)
+
+type HiddenTypeAlias = subpackage.Hidden

cmd/gentypes/test/hiddentypealias_gen.go

@@ -0,0 +1,14 @@
+package subpackage
+
+type Hidden struct {
+	Hidden string
+}
+
+func (h *Hidden) MarshalMsgpack() ([]byte, error) {
+	return []byte(h.Hidden), nil
+}
+
+func (h *Hidden) UnmarshalMsgpack(bytes []byte) error {
+	h.Hidden = string(bytes)
+	return nil
+}