Use ordered map to guarantee consistency of JSON ordering

example_test.go

@@ -82,52 +82,52 @@ func Example() {
 	// Version 1 output:
 	// [
 	//   {
-	//     "name": "Alice",
-	//     "username": "alice"
+	//     "username": "alice",
+	//     "name": "Alice"
 	//   },
 	//   {
-	//     "name": "Bob",
-	//     "username": "bob"
+	//     "username": "bob",
+	//     "name": "Bob"
 	//   }
 	// ]
 	//
 	// Version 2 output:
 	// [
 	//   {
+	//     "username": "alice",
 	//     "name": "Alice",
 	//     "roles": [
 	//       "user",
 	//       "admin"
-	//     ],
-	//     "username": "alice"
+	//     ]
 	//   },
 	//   {
+	//     "username": "bob",
 	//     "name": "Bob",
 	//     "roles": [
 	//       "user"
-	//     ],
-	//     "username": "bob"
+	//     ]
 	//   }
 	// ]
 	//
 	// Version 2 output with personal group too:
 	// [
 	//   {
+	//     "username": "alice",
 	//     "email": "[email protected]",
 	//     "name": "Alice",
 	//     "roles": [
 	//       "user",
 	//       "admin"
-	//     ],
-	//     "username": "alice"
+	//     ]
 	//   },
 	//   {
+	//     "username": "bob",
 	//     "email": "[email protected]",
 	//     "name": "Bob",
 	//     "roles": [
 	//       "user"
-	//     ],
-	//     "username": "bob"
+	//     ]
 	//   }
 	// ]
 }

go.mod

@@ -5,6 +5,7 @@ go 1.20
 require (
 	github.com/hashicorp/go-version v1.6.0
 	github.com/stretchr/testify v1.9.0
+	gitlab.com/c0b/go-ordered-json v0.0.0-20201030195603-febf46534d5a
 )
 
 require (

go.sum

@@ -6,6 +6,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+gitlab.com/c0b/go-ordered-json v0.0.0-20201030195603-febf46534d5a h1:DxppxFKRqJ8WD6oJ3+ZXKDY0iMONQDl5UTg2aTyHh8k=
+gitlab.com/c0b/go-ordered-json v0.0.0-20201030195603-febf46534d5a/go.mod h1:NREvu3a57BaK0R1+ztrEzHWiZAihohNLQ6trPxlIqZI=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

sheriff.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/go-version"
+	"gitlab.com/c0b/go-ordered-json"
 )
 
 // Options determine which struct fields are being added to the output map.
@@ -82,7 +83,7 @@ func Marshal(options *Options, data interface{}) (interface{}, error) {
 		return marshalValue(options, v)
 	}
 
-	dest := make(map[string]interface{})
+	dest := ordered.NewOrderedMap()
 
 	for i := 0; i < t.NumField(); i++ {
 		field := t.Field(i)
@@ -197,13 +198,18 @@ func Marshal(options *Options, data interface{}) (interface{}, error) {
 
 		// when a composition field we want to bring the child
 		// nodes to the top
-		nestedVal, ok := v.(map[string]interface{})
+		nestedVal, ok := v.(*ordered.OrderedMap)
 		if isEmbeddedField && ok {
-			for key, value := range nestedVal {
-				dest[key] = value
+			iter := nestedVal.EntriesIter()
+			for {
+				pair, ok := iter()
+				if !ok {
+					break
+				}
+				dest.Set(pair.Key, pair.Value)
 			}
 		} else {
-			dest[jsonTag] = v
+			dest.Set(jsonTag, v)
 		}
 	}
 
@@ -268,13 +274,13 @@ func marshalValue(options *Options, v reflect.Value) (interface{}, error) {
 		if mapKeys[0].Kind() != reflect.String {
 			return nil, MarshalInvalidTypeError{t: mapKeys[0].Kind(), data: val}
 		}
-		dest := make(map[string]interface{})
+		dest := ordered.NewOrderedMap()
 		for _, key := range mapKeys {
 			d, err := marshalValue(options, v.MapIndex(key))
 			if err != nil {
 				return nil, err
 			}
-			dest[key.String()] = d
+			dest.Set(key.String(), d)
 		}
 		return dest, nil
 	}