remove DOCKER_CLI_DISABLE_OAUTH_LOGIN escape hatch

This code was added in 846ecf59ff as an
escape hatch in case the new OAuth login flow would cause problems.
We have not received reports where the new flow caused problems, and
searching the internet shows no mentions of the env-var.

This env-var was not documented, so we can remove it.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/registry/login.go

@@ -5,8 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"os"
-	"strconv"
 	"strings"
 
 	"github.com/containerd/errdefs"
@@ -183,19 +181,6 @@ func loginWithStoredCredentials(ctx context.Context, dockerCLI command.Cli, auth
 	return response.Status, err
 }
 
-const oauthLoginEscapeHatchEnvVar = "DOCKER_CLI_DISABLE_OAUTH_LOGIN"
-
-func isOauthLoginDisabled() bool {
-	if v := os.Getenv(oauthLoginEscapeHatchEnvVar); v != "" {
-		enabled, err := strconv.ParseBool(v)
-		if err != nil {
-			return false
-		}
-		return enabled
-	}
-	return false
-}
-
 func loginUser(ctx context.Context, dockerCLI command.Cli, opts loginOptions, defaultUsername, serverAddress string) (msg string, _ error) {
 	// Some links documenting this:
 	// - https://code.google.com/archive/p/mintty/issues/56
@@ -209,7 +194,7 @@ func loginUser(ctx context.Context, dockerCLI command.Cli, opts loginOptions, de
 	}
 
 	// If we're logging into the index server and the user didn't provide a username or password, use the device flow
-	if serverAddress == registry.IndexServer && opts.user == "" && opts.password == "" && !isOauthLoginDisabled() {
+	if serverAddress == registry.IndexServer && opts.user == "" && opts.password == "" {
 		var err error
 		msg, err = loginWithDeviceCodeFlow(ctx, dockerCLI)
 		// if the error represents a failure to initiate the device-code flow,

cli/command/registry/login_test.go

@@ -497,50 +497,6 @@ func TestLoginTermination(t *testing.T) {
 	}
 }
 
-func TestIsOauthLoginDisabled(t *testing.T) {
-	testCases := []struct {
-		envVar   string
-		disabled bool
-	}{
-		{
-			envVar:   "",
-			disabled: false,
-		},
-		{
-			envVar:   "bork",
-			disabled: false,
-		},
-		{
-			envVar:   "0",
-			disabled: false,
-		},
-		{
-			envVar:   "false",
-			disabled: false,
-		},
-		{
-			envVar:   "true",
-			disabled: true,
-		},
-		{
-			envVar:   "TRUE",
-			disabled: true,
-		},
-		{
-			envVar:   "1",
-			disabled: true,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Setenv(oauthLoginEscapeHatchEnvVar, tc.envVar)
-
-		disabled := isOauthLoginDisabled()
-
-		assert.Equal(t, disabled, tc.disabled)
-	}
-}
-
 func TestLoginValidateFlags(t *testing.T) {
 	for _, tc := range []struct {
 		name        string

e2e/registry/login_test.go

@@ -32,25 +32,3 @@ func TestOauthLogin(t *testing.T) {
 	output, _ := io.ReadAll(p)
 	assert.Check(t, strings.Contains(string(output), "USING WEB-BASED LOGIN"), string(output))
 }
-
-func TestLoginWithEscapeHatch(t *testing.T) {
-	t.Parallel()
-	loginCmd := exec.Command("docker", "login")
-	loginCmd.Env = append(loginCmd.Env, "DOCKER_CLI_DISABLE_OAUTH_LOGIN=1")
-
-	p, err := pty.Start(loginCmd)
-	assert.NilError(t, err)
-	defer func() {
-		_ = loginCmd.Wait()
-		_ = p.Close()
-	}()
-
-	time.Sleep(1 * time.Second)
-	pid := loginCmd.Process.Pid
-	t.Logf("terminating PID %d", pid)
-	err = syscall.Kill(pid, syscall.SIGTERM)
-	assert.NilError(t, err)
-
-	output, _ := io.ReadAll(p)
-	assert.Check(t, strings.Contains(string(output), "Username:"), string(output))
-}