// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// The linkcheck command finds missing links in the godoc website.
// It crawls a URL recursively and notes URLs and URL fragments
// that it's seen and prints a report of missing links at the end.
package main

import (
	"errors"
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"

---
title: "Go, Backwards Compatibility, and GODEBUG"
layout: article
---

<!--
This document is kept in the Go repo, not x/website,
because it documents the full list of known GODEBUG settings,
which are tied to a specific release.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.

pkg go/token, method (*File) MergeLine(int)
pkg html/template, type Template struct, Tree *parse.Tree
pkg image/color/palette, var Plan9 []color.Color
pkg image/color/palette, var WebSafe []color.Color
pkg image/draw, method (Op) Draw(Image, image.Rectangle, image.Image, image.Point)
pkg image/draw, type Drawer interface { Draw }