Custom scopes support in M2M authentication

config/auth_m2m.go

@@ -31,7 +31,7 @@ func (c M2mCredentials) Configure(ctx context.Context, cfg *Config) (credentials
 		ClientSecret: cfg.ClientSecret,
 		AuthStyle:    oauth2.AuthStyleInHeader,
 		TokenURL:     endpoints.TokenEndpoint,
-		Scopes:       []string{"all-apis"},
+		Scopes:       cfg.GetScopes(),
 	}).TokenSource(ctx)
 
 	visitor := refreshableVisitor(ts)

config/auth_m2m_test.go

@@ -1,12 +1,13 @@
 package config
 
 import (
+	"errors"
+	"net/http"
 	"net/url"
 	"testing"
 
 	"github.com/databricks/databricks-sdk-go/credentials/u2m"
 	"github.com/databricks/databricks-sdk-go/httpclient/fixtures"
-	"github.com/stretchr/testify/require"
 	"golang.org/x/oauth2"
 )
 
@@ -90,5 +91,82 @@ func TestM2mNotSupported(t *testing.T) {
 			},
 		},
 	})
-	require.ErrorIs(t, err, u2m.ErrOAuthNotSupported)
+	if !errors.Is(err, u2m.ErrOAuthNotSupported) {
+		t.Errorf("got error %v, want %v", err, u2m.ErrOAuthNotSupported)
+	}
+}
+
+func TestM2M_Scopes(t *testing.T) {
+	tests := []struct {
+		name   string
+		scopes []string
+		want   string
+	}{
+		{
+			name:   "nil scopes uses default",
+			scopes: nil,
+			want:   "all-apis",
+		},
+		{
+			name:   "empty scopes uses default",
+			scopes: []string{},
+			want:   "all-apis",
+		},
+		{
+			name:   "single scope",
+			scopes: []string{"dashboards"},
+			want:   "dashboards",
+		},
+		{
+			name:   "multiple scopes are sorted",
+			scopes: []string{"jobs", "files:read", "mlflow"},
+			want:   "files:read jobs mlflow",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			transport := fixtures.MappingTransport{
+				"GET /oidc/.well-known/oauth-authorization-server": {
+					Response: u2m.OAuthAuthorizationServer{
+						AuthorizationEndpoint: "https://localhost/auth",
+						TokenEndpoint:         "https://localhost/token",
+					},
+				},
+				"POST /token": {
+					// The scope assertion: verifies the SDK sends the correct scope parameter.
+					ExpectedRequest: url.Values{
+						"grant_type": {"client_credentials"},
+						"scope":      {tt.want},
+					},
+					Response: oauth2.Token{
+						TokenType:   "Bearer",
+						AccessToken: "test-token",
+					},
+				},
+			}
+
+			cfg := &Config{
+				Host:          "a",
+				ClientID:      "b",
+				ClientSecret:  "c",
+				AuthType:      "oauth-m2m",
+				Scopes:        tt.scopes,
+				HTTPTransport: transport,
+				ConfigFile:    "/dev/null",
+			}
+
+			req, err := http.NewRequest("GET", "http://localhost", nil)
+			if err != nil {
+				t.Fatalf("http.NewRequest(): unexpected error: %v", err)
+			}
+			err = cfg.Authenticate(req)
+			if err != nil {
+				t.Fatalf("Authenticate(): unexpected error: %v", err)
+			}
+			if got, want := req.Header.Get("Authorization"), "Bearer test-token"; got != want {
+				t.Errorf("Authorization header: got %q, want %q", got, want)
+			}
+		})
+	}
 }