before merging in essential fixes.

cmd/yamltool/diff.go

@@ -0,0 +1,103 @@
+package main
+
+import (
+	"fmt"
+	"github.com/goccy/go-yaml"
+	"github.com/spf13/cobra"
+	"os"
+	"reflect"
+)
+
+// hack to be able to compare slices and dictionires that cannot be put into a map.
+func strval(v any) string {
+	return fmt.Sprintf("%v", v)
+}
+
+func subtract(yaml2 yaml.MapSlice, yaml1 yaml.MapSlice) yaml.MapSlice {
+	res := make(yaml.MapSlice, 0)
+	for _, item := range yaml2 {
+		k := item.Key
+		v2 := item.Value
+		v1 := yaml1.ToMap()[k]
+		switch {
+		case reflect.DeepEqual(v1, v2):
+			// delete is implicit by not copying to the output
+		case Type(v1) == Map && Type(v2) == Map:
+			diff := subtract(v2.(yaml.MapSlice), v1.(yaml.MapSlice))
+			if len(diff) > 0 {
+				res = append(res, item)
+			}
+		case Type(v1) == Slice && Type(v2) == Slice:
+
+			v2set := make(map[string]bool)
+			v1set := make(map[string]bool)
+			stringToValue := make(map[any]any)
+			for _, v := range v2.([]any) {
+				sval := strval(v)
+				stringToValue[sval] = v
+				v2set[sval] = true
+			}
+			for _, v := range v1.([]any) {
+				v1set[strval(v)] = true
+			}
+			s := make([]any, 0)
+			for k2, _ := range v2set {
+				if v1set[k2] {
+					if VERBOSITY == 2 {
+						s = append(s, "<UNMODIFIED>")
+					} else if VERBOSITY == 3 {
+						s = append(s, stringToValue[k2])
+					}
+				} else {
+					s = append(s, stringToValue[k2])
+				}
+			}
+			res = append(res, yaml.MapItem{
+				Key:   k,
+				Value: s,
+			})
+		default:
+			res = append(res, item)
+		}
+	}
+	return res
+}
+
+func diff(cmd *cobra.Command, args []string) error {
+	if len(args) != 2 {
+		return fmt.Errorf("Expected 2 files")
+	}
+	if VERBOSITY < 0 || VERBOSITY > 3 {
+		return fmt.Errorf("Array verbosity out of range")
+	}
+	file1 := args[0]
+	file2 := args[1]
+
+	yaml1 := parse(read(file1))
+	yaml2 := parse(read(file2))
+
+	diff1 := subtract(yaml2, yaml1)
+	diff2 := make(yaml.MapSlice, 0)
+	if SYMMETRIC_DIFF {
+		diff2 = subtract(yaml1, yaml2)
+	}
+
+	diff := diff1
+	if SYMMETRIC_DIFF {
+		diff = make(yaml.MapSlice, 0)
+		diff = append(diff,
+			yaml.MapItem{Key: "forward", Value: diff1},
+			yaml.MapItem{Key: "backward", Value: diff2},
+		)
+	}
+
+	if VERBOSITY > 0 {
+		if err := encode(os.Stdout, diff); err != nil {
+			return err
+		}
+	}
+	if len(diff1) > 0 || len(diff2) > 0 {
+		os.Exit(1)
+	}
+	return nil
+}