bonus: logout error if GITHUB_TOKEN is set

pkg/cmd/auth/logout/logout.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"os"
 
 	"github.com/AlecAivazis/survey/v2"
 	"github.com/MakeNowJust/heredoc"
@@ -62,7 +63,10 @@ func NewCmdLogout(f *cmdutil.Factory, runF func(*LogoutOptions) error) *cobra.Co
 }
 
 func logoutRun(opts *LogoutOptions) error {
-	// TODO check for GITHUB_TOKEN and error if found
+	if os.Getenv("GITHUB_TOKEN") != "" {
+		return errors.New("GITHUB_TOKEN is set in your environment. If you no longer want to use it with gh, please unset it.")
+	}
+
 	isTTY := opts.IO.IsStdinTTY() && opts.IO.IsStdoutTTY()
 
 	hostname := opts.Hostname

pkg/cmd/auth/logout/logout_test.go

@@ -3,6 +3,7 @@ package logout
 import (
 	"bytes"
 	"net/http"
+	"os"
 	"regexp"
 	"testing"
 
@@ -183,6 +184,7 @@ func Test_logoutRun_nontty(t *testing.T) {
 		cfgHosts  []string
 		wantHosts string
 		wantErr   *regexp.Regexp
+		ghtoken   string
 	}{
 		{
 			name:    "no arguments",
@@ -211,10 +213,21 @@ func Test_logoutRun_nontty(t *testing.T) {
 			},
 			wantErr: regexp.MustCompile(`not logged in to any hosts`),
 		},
+		{
+			name:    "gh token is set",
+			opts:    &LogoutOptions{},
+			ghtoken: "abc123",
+			wantErr: regexp.MustCompile(`GITHUB_TOKEN is set in your environment`),
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			ghtoken := os.Getenv("GITHUB_TOKEN")
+			defer func() {
+				os.Setenv("GITHUB_TOKEN", ghtoken)
+			}()
+			os.Setenv("GITHUB_TOKEN", tt.ghtoken)
 			io, _, _, stderr := iostreams.Test()
 
 			io.SetStdinTTY(false)