diff now does sort first

cmd/yamltool/diff.go

@@ -74,6 +74,15 @@ func subtract(yaml2 yaml.MapSlice, yaml1 yaml.MapSlice) yaml.MapSlice {
 	return res
 }
 
+func compare(yaml1 yaml.MapSlice, yaml2 yaml.MapSlice) (yaml.MapSlice, yaml.MapSlice) {
+	((MapSlice)(yaml1)).Sort()
+	((MapSlice)(yaml2)).Sort()
+
+	diff1 := subtract(yaml2, yaml1)
+	diff2 := subtract(yaml1, yaml2)
+	return diff1, diff2
+}
+
 func diff(cmd *cobra.Command, args []string) error {
 	if len(args) != 2 {
 		return fmt.Errorf("Expected 2 files")
@@ -102,10 +111,10 @@ func diff(cmd *cobra.Command, args []string) error {
 		return fmt.Errorf("%s: %w", file2, err)
 	}
 
-	diff1 := subtract(yaml2, yaml1)
+	diff1, backwardDiff := compare(yaml1, yaml2)
 	diff2 := make(yaml.MapSlice, 0)
 	if SYMMETRIC_DIFF {
-		diff2 = subtract(yaml1, yaml2)
+		diff2 = backwardDiff
 	}
 
 	diff := diff1

cmd/yamltool/diff_test.go

@@ -0,0 +1,76 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/goccy/go-yaml"
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+)
+
+type DiffSuite struct {
+	suite.Suite
+}
+
+func TestDiffSuite(t *testing.T) {
+	suite.Run(t, new(DiffSuite))
+}
+
+func (s *DiffSuite) TestCompareIgnoresTopLevelMapKeyOrder() {
+	diff1, diff2 := s.compareDocuments(`
+first: 1
+second: 2
+`, `
+second: 2
+first: 1
+`)
+
+	require.Empty(s.T(), diff1)
+	require.Empty(s.T(), diff2)
+}
+
+func (s *DiffSuite) TestCompareIgnoresMapKeyOrderInArray() {
+	diff1, diff2 := s.compareDocuments(`
+items:
+  - name: alpha
+    value: 1
+  - name: beta
+    value: 2
+`, `
+items:
+  - value: 1
+    name: alpha
+  - value: 2
+    name: beta
+`)
+
+	require.Empty(s.T(), diff1)
+	require.Empty(s.T(), diff2)
+}
+
+func (s *DiffSuite) TestCompareStillDetectsChangedMapValue() {
+	diff1, diff2 := s.compareDocuments(`
+items:
+  - name: alpha
+    value: 1
+`, `
+items:
+  - value: 2
+    name: alpha
+`)
+
+	require.NotEmpty(s.T(), diff1)
+	require.NotEmpty(s.T(), diff2)
+}
+
+func (s *DiffSuite) compareDocuments(yaml1Data, yaml2Data string) (yaml.MapSlice, yaml.MapSlice) {
+	s.T().Helper()
+
+	yaml1, err := parse([]byte(yaml1Data))
+	require.NoError(s.T(), err)
+	yaml2, err := parse([]byte(yaml2Data))
+	require.NoError(s.T(), err)
+
+	diff1, diff2 := compare(yaml1, yaml2)
+	return diff1, diff2
+}

cmd/yamltool/parse.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"fmt"
+	"os"
 
 	"github.com/goccy/go-yaml"
 	"github.com/spf13/cobra"
@@ -25,10 +26,14 @@ func parseFiles(cmd *cobra.Command, args []string) error {
 		if err != nil {
 			return err
 		}
-		_, err = parse(data)
+		decoded, err := parse(data)
 		if err != nil {
 			fmt.Printf("%s: %v\n", arg, err.Error())
 		}
+		if len(args) > 1 {
+			fmt.Printf("---\n")
+		}
+		encode(os.Stdout, decoded)
 	}
 	return nil
 }

go.mod

@@ -5,9 +5,13 @@ go 1.24.7
 require (
 	github.com/goccy/go-yaml v1.15.13
 	github.com/spf13/cobra v1.8.1
+	github.com/stretchr/testify v1.10.0
 )
 
 require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,12 +1,20 @@
 github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/goccy/go-yaml v1.15.13 h1:Xd87Yddmr2rC1SLLTm2MNDcTjeO/GYo0JGiww6gSTDg=
 github.com/goccy/go-yaml v1.15.13/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/spf13/cobra v1.8.1 h1:e5/vxKd/rZsfSJMUX1agtjeTDf+qv1/JdBF8gg5k9ZM=
 github.com/spf13/cobra v1.8.1/go.mod h1:wHxEcudfqmLYa8iTfL+OuZPbBZkmvliBWKIezN3kD9Y=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+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=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=