[permitted by the Go 1 compatibility rules](/doc/go1compat).
Even so, Go provides a mechanism called GODEBUG to
reduce the impact such changes have on Go developers
using newer toolchains to compile old code.

A GODEBUG setting is a `key=value` pair
that controls the execution of certain parts of a Go program.
The environment variable `GODEBUG`
can hold a comma-separated list of these settings.

These new behaviors are only enabled when the main Go program
is in a module with a `go.mod` `go` line using Go 1.23.0 or later.
When Go 1.23 builds older programs, the old behaviors remain in effect.
The new [GODEBUG setting](/doc/godebug) [`asynctimerchan=1`](/pkg/time/#NewTimer)
can be used to revert back to asynchronous channel behaviors

package zip

import (
	"bufio"
	"encoding/binary"
	"errors"
	"hash"
	"hash/crc32"
	"internal/godebug"
	"io"
	"io/fs"
	"os"
	"path"
	"path/filepath"
	"sort"
	"strings"
	"sync"
	"time"
)

var zipinsecurepath = godebug.New("zipinsecurepath")

var (
	ErrFormat       = errors.New("zip: not a valid zip file")

		}
		if got := fi.ModTime(); !got.Equal(test.want) {
			t.Errorf("%s: got modtime %v, want %v", test.name, got, test.want)
		}
	}
}

func TestCVE202127919(t *testing.T) {
	t.Setenv("GODEBUG", "zipinsecurepath=0")
	// Archive containing only the file "../test.txt"
	data := []byte{
		0x50, 0x4b, 0x03, 0x04, 0x14, 0x00, 0x08, 0x00,
		0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,

memory points, and so on) is pinned.

These rules are checked dynamically at runtime. The checking is
controlled by the cgocheck setting of the GODEBUG environment
variable. The default setting is GODEBUG=cgocheck=1, which implements
reasonably cheap dynamic checks. These checks may be disabled
entirely using GODEBUG=cgocheck=0. Complete checking of pointer
handling, at some cost in run time, is available by setting
GOEXPERIMENT=cgocheck2 at build time.

package tar

import (
	"errors"
	"fmt"
	"internal/godebug"
	"io/fs"
	"math"
	"path"
	"reflect"
	"strconv"
	"strings"
	"time"
)

// BUG: Use of the Uid and Gid fields in Header could overflow on 32-bit
// architectures. If a large value is encountered when decoding, the result
// stored in Header will be the truncated version.

var tarinsecurepath = godebug.New("tarinsecurepath")

var (

// built-in function recover.
//
// Starting in Go 1.21, calling panic with a nil interface value or an
// untyped nil causes a run-time error (a different panic).
// The GODEBUG setting panicnil=1 disables the run-time error.
func panic(v any)

// The recover built-in function allows a program to manage behavior of a
// panicking goroutine. Executing a call to recover inside a deferred

				}
			default:
				t.Fatalf("test %d.%d, unknown test operation: %T", i, j, tf)
			}
		}
	}
}

func TestInsecurePaths(t *testing.T) {
	t.Setenv("GODEBUG", "tarinsecurepath=0")
	for _, path := range []string{
		"../foo",
		"/foo",
		"a/b/../../../c",
	} {
		var buf bytes.Buffer
		tw := NewWriter(&buf)
		tw.WriteHeader(&Header{
			Name: path,

// Any remaining data in the current file is automatically discarded.
// At the end of the archive, Next returns the error io.EOF.
//
// If Next encounters a non-local name (as defined by [filepath.IsLocal])
// and the GODEBUG environment variable contains `tarinsecurepath=0`,
// Next returns the header with an [ErrInsecurePath] error.
// A future version of Go may introduce this behavior by default.