Fix proxy manipulation of single payload fields (#202)

* Fix proxy manipulation of single payload fields

* Remove case for *common.Payload

cmd/proxygenerator/interceptor.go

@@ -207,15 +207,10 @@ func visitPayloads(
 	parent proto.Message,
 	objs ...interface{},
 ) error {
-	for i, obj := range objs {
+	for _, obj := range objs {
 		ctx.SinglePayloadRequired = false
 
 		switch o := obj.(type) {
-			case *common.Payload:
-				if o == nil { continue }
-				no, err := visitPayload(ctx, options, parent, o)
-				if err != nil { return err }
-				objs[i] = no
 			case map[string]*common.Payload:
 				for ix, x := range o {
 					if nx, err := visitPayload(ctx, options, parent, x); err != nil {
@@ -273,6 +268,14 @@ func visitPayloads(
 				if options.SkipSearchAttributes { continue }
 				{{end}}
 				if o == nil { continue }
+				{{range $record.Payloads -}}
+				if o.{{.}} != nil {
+					no, err := visitPayload(ctx, options, o, o.{{.}})
+					if err != nil { return err }
+					o.{{.}} = no
+				}
+				{{end}}
+				{{if $record.Methods}}
 				if err := visitPayloads(
 					ctx,
 					options,
@@ -281,6 +284,7 @@ func visitPayloads(
 						o.{{.}}(),
 					{{end}}
 				); err != nil { return err }
+				{{end}}
 {{end}}
 		}
 	}
@@ -326,10 +330,11 @@ var interceptorTemplate = template.Must(template.New("interceptor").Parse(Interc
 
 // TypeRecord holds the state for a type referred to by the workflow service
 type TypeRecord struct {
-	Methods []string // List of methods on this type that can eventually lead to Payload(s)
-	Slice   bool     // The API refers to slices of this type
-	Map     bool     // The API refers to maps with this type as the value
-	Matches bool     // We found methods on this type that can eventually lead to Payload(s)
+	Methods  []string // List of methods on this type that can eventually lead to Payload(s)
+	Payloads []string // List of attributes on this type that are of type Payload
+	Slice    bool     // The API refers to slices of this type
+	Map      bool     // The API refers to maps with this type as the value
+	Matches  bool     // We found methods on this type that can eventually lead to Payload(s)
 }
 
 // isSlice returns true if a type is slice, false otherwise
@@ -411,12 +416,12 @@ func pruneRecords(input map[string]*TypeRecord) map[string]*TypeRecord {
 
 // walk iterates the methods on a type and returns whether any of them can eventually lead to Payload(s)
 // The return type for each method on this type is walked recursively to decide which methods can lead to Payload(s)
-func walk(desired []types.Type, typ types.Type, records *map[string]*TypeRecord) bool {
+func walk(desired []types.Type, typ types.Type, records *map[string]*TypeRecord, checkDirectPayload bool) bool {
 	typeName := typeName(typ)
 
 	// If this type is a slice then walk the underlying type and then make a note we need to encode slices of this type
 	if isSlice(typ) {
-		result := walk(desired, elemType(typ), records)
+		result := walk(desired, elemType(typ), records, checkDirectPayload)
 		if result {
 			record := (*records)[typeName]
 			record.Slice = true
@@ -426,7 +431,7 @@ func walk(desired []types.Type, typ types.Type, records *map[string]*TypeRecord)
 
 	// If this type is a map then walk the underlying type and then make a note we need to encode maps with values of this type
 	if isMap(typ) {
-		result := walk(desired, elemType(typ), records)
+		result := walk(desired, elemType(typ), records, checkDirectPayload)
 		if result {
 			record := (*records)[typeName]
 			record.Map = true
@@ -459,8 +464,18 @@ func walk(desired []types.Type, typ types.Type, records *map[string]*TypeRecord)
 		// All the Get... methods return the relevant protobuf as the first result
 		resultType := sig.Results().At(0).Type()
 
+		if checkDirectPayload && resultType.String() == "*go.temporal.io/api/common/v1.Payload" {
+			record.Matches = true
+			prefix, ok := strings.CutPrefix(methodName, "Get")
+			if !ok {
+				panic(fmt.Errorf("expected method to have a Get prefix: %s", methodName))
+			}
+			record.Payloads = append(record.Payloads, prefix)
+			continue
+		}
+
 		// Check if this method returns a Payload(s) or if it leads (eventually) to a Type which refers to a Payload(s)
-		if typeMatches(resultType, desired...) || walk(desired, resultType, records) {
+		if typeMatches(resultType, desired...) || walk(desired, resultType, records, checkDirectPayload) {
 			record.Matches = true
 			record.Methods = append(record.Methods, methodName)
 		}
@@ -536,10 +551,10 @@ func generateInterceptor(cfg config) error {
 		}
 
 		sig := meth.Obj().Type().(*types.Signature)
-		walk(payloadTypes, sig.Params().At(1).Type(), &payloadRecords)
-		walk(failureTypes, sig.Params().At(1).Type(), &failureRecords)
-		walk(payloadTypes, sig.Results().At(0).Type(), &payloadRecords)
-		walk(failureTypes, sig.Results().At(0).Type(), &failureRecords)
+		walk(payloadTypes, sig.Params().At(1).Type(), &payloadRecords, true)
+		walk(failureTypes, sig.Params().At(1).Type(), &failureRecords, false)
+		walk(payloadTypes, sig.Results().At(0).Type(), &payloadRecords, true)
+		walk(failureTypes, sig.Results().At(0).Type(), &failureRecords, false)
 	}
 
 	for _, meth := range typeutil.IntuitiveMethodSet(operatorService, nil) {
@@ -548,14 +563,14 @@ func generateInterceptor(cfg config) error {
 		}
 
 		sig := meth.Obj().Type().(*types.Signature)
-		walk(payloadTypes, sig.Params().At(1).Type(), &payloadRecords)
-		walk(failureTypes, sig.Params().At(1).Type(), &failureRecords)
-		walk(payloadTypes, sig.Results().At(0).Type(), &payloadRecords)
-		walk(failureTypes, sig.Results().At(0).Type(), &failureRecords)
+		walk(payloadTypes, sig.Params().At(1).Type(), &payloadRecords, true)
+		walk(failureTypes, sig.Params().At(1).Type(), &failureRecords, false)
+		walk(payloadTypes, sig.Results().At(0).Type(), &payloadRecords, true)
+		walk(failureTypes, sig.Results().At(0).Type(), &failureRecords, false)
 	}
 
-	walk(payloadTypes, workflowExecutions, &payloadRecords)
-	walk(failureTypes, workflowExecutions, &failureRecords)
+	walk(payloadTypes, workflowExecutions, &payloadRecords, true)
+	walk(failureTypes, workflowExecutions, &failureRecords, false)
 
 	payloadRecords = pruneRecords(payloadRecords)
 	failureRecords = pruneRecords(failureRecords)