base: `
proxyHeaders:
  requestId:
    disabled: true`,
			overlay: `
proxyHeaders:
  requestId:
    disabled: false`,
			result: `
proxyHeaders:
  requestId:
    disabled: false`,
		},
		{
			name: "enabled then disabled",
			base: `
proxyHeaders:
  requestId:
    disabled: false`,
			overlay: `
proxyHeaders:
  requestId:
    disabled: true`,

	}

	testCases := []struct {
		name          string
		originHeaders http.Header
		proxyHeaders  []apimirror.HTTPHeader
		want          http.Header
	}{
		{
			name: "Only Origin",
			originHeaders: http.Header{
				testHeader: []string{testHeaderValue},
			},
			proxyHeaders: []apimirror.HTTPHeader{},
			want: http.Header{
				testHeader:   []string{testHeaderValue},

func MergeProxyConfig(yaml string, proxyConfig *meshconfig.ProxyConfig) (*meshconfig.ProxyConfig, error) {
	origMetadata := proxyConfig.ProxyMetadata
	origProxyHeaders := proxyConfig.ProxyHeaders
	if err := protomarshal.ApplyYAML(yaml, proxyConfig); err != nil {
		return nil, fmt.Errorf("could not parse proxy config: %v", err)
	}
	newMetadata := proxyConfig.ProxyMetadata

func GetProxyHeaders(node *model.Proxy, push *model.PushContext, class istionetworking.ListenerClass) ProxyHeaders {
	pc := node.Metadata.ProxyConfigOrDefault(push.Mesh.DefaultConfig)
	return GetProxyHeadersFromProxyConfig(pc, class)
}

func GetProxyHeadersFromProxyConfig(pc *meshconfig.ProxyConfig, class istionetworking.ListenerClass) ProxyHeaders {
	base := ProxyHeaders{
		ServerName:                 EnvoyServerName,

	httpProtoOpts := &core.Http1ProtocolOptions{}
	if features.HTTP10 || enableHTTP10(node.Metadata.HTTP10) {
		httpProtoOpts.AcceptHttp_10 = true
	}
	xffNumTrustedHops := uint32(0)

	// Gateways do not use ProxyHeaders for XFCC as there is an existing field in gateway topology that is used instead.
	forwardClientCertDetails := util.MeshConfigToEnvoyForwardClientCertDetails(meshconfig.ForwardClientCertDetails_SANITIZE_SET)