fix(auth): improve error reporting when token lookup fails

pkg/api/client_options.go

@@ -94,8 +94,12 @@ func resolveOptions(opts ClientOptions) (ClientOptions, error) {
 		opts.Host, _ = auth.DefaultHost()
 	}
 	if opts.AuthToken == "" {
-		opts.AuthToken, _ = auth.TokenForHost(opts.Host)
+		source := ""
+		opts.AuthToken, source = auth.TokenForHost(opts.Host)
 		if opts.AuthToken == "" {
+			if source != "" && source != "default" {
+				return ClientOptions{}, fmt.Errorf("authentication token not found for host %s: %s", opts.Host, source)
+			}
 			return ClientOptions{}, fmt.Errorf("authentication token not found for host %s", opts.Host)
 		}
 	}

pkg/api/client_options_test.go

@@ -49,6 +49,21 @@ func TestResolveOptions(t *testing.T) {
 	}
 }
 
+func TestResolveOptions_ReturnsTokenLookupFailureReason(t *testing.T) {
+	testutils.StubConfig(t, "")
+	t.Setenv("GH_TOKEN", "")
+	t.Setenv("GITHUB_TOKEN", "")
+	t.Setenv("GH_ENTERPRISE_TOKEN", "")
+	t.Setenv("GITHUB_ENTERPRISE_TOKEN", "")
+	t.Setenv("GH_PATH", "/path/to/missing/gh")
+
+	_, err := resolveOptions(ClientOptions{Host: "github.com"})
+
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "authentication token not found for host github.com")
+	assert.Contains(t, err.Error(), "failed to run `gh auth token`")
+}
+
 func TestOptionsNeedResolution(t *testing.T) {
 	tests := []struct {
 		name string

pkg/auth/auth.go

@@ -32,7 +32,7 @@ const (
 // host. The source can be either an environment variable, configuration file, or the system
 // keyring. In the latter case, this shells out to "gh auth token" to obtain the token.
 //
-// Returns "", "default" if no applicable token is found.
+// Returns an empty token and a source that can either be "default" or a reason why lookup failed.
 func TokenForHost(host string) (string, string) {
 	if token, source := TokenFromEnvOrConfig(host); token != "" {
 		return token, source
@@ -43,10 +43,14 @@ func TokenForHost(host string) (string, string) {
 		ghExe, _ = safeexec.LookPath("gh")
 	}
 
-	if ghExe != "" {
-		if token, source := tokenFromGh(ghExe, host); token != "" {
-			return token, source
-		}
+	if ghExe == "" {
+		return "", "gh executable not found in PATH"
+	}
+
+	if token, source := tokenFromGh(ghExe, host); token != "" {
+		return token, source
+	} else if source != "" {
+		return "", source
 	}
 
 	return "", defaultSource
@@ -101,11 +105,20 @@ func tokenForHost(cfg *config.Config, host string) (string, string) {
 
 func tokenFromGh(path string, host string) (string, string) {
 	cmd := exec.Command(path, "auth", "token", "--secure-storage", "--hostname", host)
-	result, err := cmd.Output()
+	result, err := cmd.CombinedOutput()
 	if err != nil {
-		return "", "gh"
+		details := strings.TrimSpace(string(result))
+		if details == "" {
+			details = err.Error()
+		}
+		return "", fmt.Sprintf("failed to run `gh auth token`: %s", details)
+	}
+
+	token := strings.TrimSpace(string(result))
+	if token == "" {
+		return "", "gh did not return an authentication token"
 	}
-	return strings.TrimSpace(string(result)), "gh"
+	return token, "gh"
 }
 
 // KnownHosts retrieves a list of hosts that have corresponding

pkg/auth/auth_test.go

@@ -3,6 +3,7 @@ package auth
 import (
 	"testing"
 
+	"github.com/cli/go-gh/v2/internal/testutils"
 	"github.com/cli/go-gh/v2/pkg/config"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -147,6 +148,16 @@ func TestTokenForHost(t *testing.T) {
 	}
 }
 
+func TestTokenForHost_ReturnsReasonWhenGhCommandFails(t *testing.T) {
+	testutils.StubConfig(t, testNoHostsConfigData())
+	t.Setenv("GH_PATH", "/path/to/missing/gh")
+
+	token, source := TokenForHost("github.com")
+
+	assert.Equal(t, "", token)
+	assert.Contains(t, source, "failed to run `gh auth token`")
+}
+
 func TestDefaultHost(t *testing.T) {
 	tests := []struct {
 		name         string
@@ -399,8 +410,11 @@ func TestNormalizeHostname(t *testing.T) {
 }
 
 func testNoHostsConfig() *config.Config {
-	var data = ``
-	return config.ReadFromString(data)
+	return config.ReadFromString(testNoHostsConfigData())
+}
+
+func testNoHostsConfigData() string {
+	return ``
 }
 
 func testSingleHostConfig() *config.Config {