refactor: implement deepCopy function to prevent input data mutations in apply.go

Signed-off-by: Evsyukov Denis <denis.evsyukov@flant.com>

Author: Evsyukov Denis

pkg/filter/jq/apply.go

@@ -1,6 +1,7 @@
 package jq
 
 import (
+	"encoding/json"
 	"errors"
 	"maps"
 
@@ -25,8 +26,7 @@ func (f *Filter) ApplyFilter(jqFilter string, data map[string]any) (map[string]a
 	}
 
 	// gojs will normalize numbers in the input data, we should create new map for prevent changes in input data
-	workData := make(map[string]any)
-	maps.Copy(workData, data)
+	workData := deepCopy(data)
 	iter := query.Run(workData)
 	result := make(map[string]any)
 	for {
@@ -52,3 +52,10 @@ func (f *Filter) ApplyFilter(jqFilter string, data map[string]any) (map[string]a
 func (f *Filter) FilterInfo() string {
 	return "jqFilter implementation: using itchyny/gojq"
 }
+
+func deepCopy(input map[string]any) map[string]any {
+	data, _ := json.Marshal(input)
+	var output map[string]any
+	_ = json.Unmarshal(data, &output)
+	return output
+}

pkg/filter/jq/apply_test.go

@@ -72,3 +72,26 @@ func Test_ApplyFilter_InvalidJson(t *testing.T) {
 	g.Expect(err).Should(BeNil())
 	g.Expect(result).ShouldNot(BeNil())
 }
+
+func Test_deepCopy(t *testing.T) {
+	g := NewWithT(t)
+
+	original := map[string]any{
+		"name": "John",
+		"age":  30.0,
+		"address": map[string]any{
+			"city":  "New York",
+			"state": "NY",
+		},
+	}
+
+	cp := deepCopy(original)
+
+	g.Expect(cp).Should(Equal(original))
+
+	cp["name"] = "Jane"
+	cp["address"].(map[string]any)["city"] = "Los Angeles"
+
+	g.Expect(original["name"]).Should(Equal("John"))
+	g.Expect(original["address"].(map[string]any)["city"]).Should(Equal("New York"))
+}