all: sync with master

internal/next/jsonpatch/jsonpatch.go

@@ -0,0 +1,43 @@
+// Package jsonpatch contains utilities for JSON Merge Patch APIs.
+//
+// See https://www.rfc-editor.org/rfc/rfc7396.
+package jsonpatch
+
+import (
+	"bytes"
+	"encoding/json"
+
+	"github.com/AdguardTeam/golibs/errors"
+)
+
+// NonRemovable is a type that prevents JSON null from being used to try and
+// remove a value.
+type NonRemovable[T any] struct {
+	Value T
+	IsSet bool
+}
+
+// type check
+var _ json.Unmarshaler = (*NonRemovable[struct{}])(nil)
+
+// UnmarshalJSON implements the [json.Unmarshaler] interface for *NonRemovable.
+func (v *NonRemovable[T]) UnmarshalJSON(b []byte) (err error) {
+	if v == nil {
+		return errors.Error("jsonpatch.NonRemovable is nil")
+	}
+
+	if bytes.Equal(b, []byte("null")) {
+		return errors.Error("property cannot be removed")
+	}
+
+	v.IsSet = true
+
+	return json.Unmarshal(b, &v.Value)
+}
+
+// Set sets ptr if the value has been provided.
+func (v NonRemovable[T]) Set(ptr *T) {
+	if v.IsSet {
+		*ptr = v.Value
+	}
+}