fix https://github.com/kataras/iris/issues/1273

Former-commit-id: 2b48b9b912e9eb8f5f2c6d413907dbfdae857e08

hero/func_result.go

@@ -211,7 +211,6 @@ func DispatchFuncResult(ctx context.Context, errorHandler ErrorHandler, values [
 	)
 
 	for _, v := range values {
-
 		// order of these checks matters
 		// for example, first  we need to check for status code,
 		// secondly the string (for content type and content)...
@@ -310,27 +309,46 @@ func DispatchFuncResult(ctx context.Context, errorHandler ErrorHandler, values [
 			// it's raw content, get the latest
 			content = value
 		case compatibleErr:
-			if value != nil { // it's always not nil but keep it here.
-				if errorHandler != nil {
-					errorHandler.HandleError(ctx, value)
-					break
-				}
-
-				err = value
-				if statusCode < 400 {
-					statusCode = DefaultErrStatusCode
-				}
-				break // break on first error, error should be in the end but we
-				// need to know break the dispatcher if any error.
-				// at the end; we don't want to write anything to the response if error is not nil.
+			if value == nil || di.IsNil(v) {
+				continue
 			}
+
+			if errorHandler != nil {
+				errorHandler.HandleError(ctx, value)
+				break
+			}
+
+			err = value
+			if statusCode < 400 {
+				statusCode = DefaultErrStatusCode
+			}
+			break // break on first error, error should be in the end but we
+			// need to know break the dispatcher if any error.
+			// at the end; we don't want to write anything to the response if error is not nil.
+
 		default:
 			// else it's a custom struct or a dispatcher, we'll decide later
 			// because content type and status code matters
 			// do that check in order to be able to correctly dispatch:
 			// (customStruct, error) -> customStruct filled and error is nil
-			if custom == nil && f != nil {
-				custom = f
+			if custom == nil {
+				// if it's a pointer to struct/map.
+
+				if di.IsNil(v) {
+					// if just a ptr to struct with no content type given
+					// then try to get the previous response writer's content type,
+					// and if that is empty too then force-it to application/json
+					// as the default content type we use for structs/maps.
+					contentType = ctx.GetContentType()
+					if contentType == "" {
+						contentType = context.ContentJSONHeaderValue
+					}
+					continue
+				}
+
+				if value != nil {
+					custom = value // content type will be take care later on.
+				}
 			}
 		}
 	}