add authErr to users mailbox check (#3744)

license issues can produce an authenticationError when retrieving a user's inbox.  This catches that error and treats it as a "mailbox not availble" condition.

---

#### Does this PR need a docs update or release note?

- [x] ⛔ No

#### Type of change

- [x] 🐛 Bugfix

#### Issue(s)

* #3743

#### Test Plan

- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/m365/graph/errors.go

@@ -26,6 +26,9 @@ import (
 type errorCode string
 
 const (
+	// this auth error is a catch-all used by graph in a variety of cases:
+	// users without licenses, bad jwts, missing account permissions, etc.
+	AuthenticationError errorCode = "AuthenticationError"
 	// cannotOpenFileAttachment happen when an attachment is
 	// inaccessible. The error message is usually "OLE conversion
 	// failed for an attachment."
@@ -103,6 +106,10 @@ var (
 	ErrResourceOwnerNotFound = clues.New("resource owner not found in tenant")
 )
 
+func IsErrAuthenticationError(err error) bool {
+	return hasErrorCode(err, AuthenticationError)
+}
+
 func IsErrDeletedInFlight(err error) bool {
 	if errors.Is(err, ErrDeletedInFlight) {
 		return true

src/internal/m365/graph/errors_test.go

@@ -73,6 +73,40 @@ func (suite *GraphErrorsUnitSuite) TestIsErrConnectionReset() {
 	}
 }
 
+func (suite *GraphErrorsUnitSuite) TestIsErrAuthenticationError() {
+	table := []struct {
+		name   string
+		err    error
+		expect assert.BoolAssertionFunc
+	}{
+		{
+			name:   "nil",
+			err:    nil,
+			expect: assert.False,
+		},
+		{
+			name:   "non-matching",
+			err:    assert.AnError,
+			expect: assert.False,
+		},
+		{
+			name:   "non-matching oDataErr",
+			err:    odErr("fnords"),
+			expect: assert.False,
+		},
+		{
+			name:   "authenticationError oDataErr",
+			err:    odErr(string(AuthenticationError)),
+			expect: assert.True,
+		},
+	}
+	for _, test := range table {
+		suite.Run(test.name, func() {
+			test.expect(suite.T(), IsErrAuthenticationError(test.err))
+		})
+	}
+}
+
 func (suite *GraphErrorsUnitSuite) TestIsErrDeletedInFlight() {
 	table := []struct {
 		name   string

src/pkg/services/m365/api/users.go

@@ -195,16 +195,9 @@ func (c Users) GetInfo(ctx context.Context, userID string) (*UserInfo, error) {
 	// if they cannot, we can assume they are ineligible for exchange backups.
 	inbx, err := c.GetMailInbox(ctx, userID)
 	if err != nil {
-		err = graph.Stack(ctx, err)
+		if err := EvaluateMailboxError(graph.Stack(ctx, err)); err != nil {
-
-		if graph.IsErrUserNotFound(err) {
-			logger.CtxErr(ctx, err).Error("user not found")
-			return nil, clues.Stack(graph.ErrResourceOwnerNotFound, err)
-		}
-
-		if !graph.IsErrExchangeMailFolderNotFound(err) {
 			logger.CtxErr(ctx, err).Error("getting user's mail folder")
-			return nil, clues.Stack(err)
+			return nil, err
 		}
 
 		logger.Ctx(ctx).Info("resource owner does not have a mailbox enabled")
@@ -253,6 +246,26 @@ func (c Users) GetInfo(ctx context.Context, userID string) (*UserInfo, error) {
 	return userInfo, nil
 }
 
+// EvaluateMailboxError checks whether the provided error can be interpreted
+// as "user does not have a mailbox", or whether it is some other error.  If
+// the former (no mailbox), returns nil, otherwise returns an error.
+func EvaluateMailboxError(err error) error {
+	if err == nil {
+		return nil
+	}
+
+	// must occur before MailFolderNotFound, due to overlapping cases.
+	if graph.IsErrUserNotFound(err) {
+		return clues.Stack(graph.ErrResourceOwnerNotFound, err)
+	}
+
+	if graph.IsErrExchangeMailFolderNotFound(err) || graph.IsErrAuthenticationError(err) {
+		return nil
+	}
+
+	return err
+}
+
 func (c Users) getMailboxSettings(
 	ctx context.Context,
 	userID string,

src/pkg/services/m365/api/users_test.go

@@ -66,6 +66,55 @@ func (suite *UsersUnitSuite) TestValidateUser() {
 	}
 }
 
+func (suite *UsersUnitSuite) TestEvaluateMailboxError() {
+	table := []struct {
+		name   string
+		err    error
+		expect func(t *testing.T, err error)
+	}{
+		{
+			name: "nil",
+			err:  nil,
+			expect: func(t *testing.T, err error) {
+				assert.NoError(t, err, clues.ToCore(err))
+			},
+		},
+		{
+			name: "mail inbox err - user not found",
+			err:  odErr(string(graph.RequestResourceNotFound)),
+			expect: func(t *testing.T, err error) {
+				assert.ErrorIs(t, err, graph.ErrResourceOwnerNotFound, clues.ToCore(err))
+			},
+		},
+		{
+			name: "mail inbox err - user not found",
+			err:  odErr(string(graph.MailboxNotEnabledForRESTAPI)),
+			expect: func(t *testing.T, err error) {
+				assert.NoError(t, err, clues.ToCore(err))
+			},
+		},
+		{
+			name: "mail inbox err - authenticationError",
+			err:  odErr(string(graph.AuthenticationError)),
+			expect: func(t *testing.T, err error) {
+				assert.NoError(t, err, clues.ToCore(err))
+			},
+		},
+		{
+			name: "mail inbox err - other error",
+			err:  odErrMsg("somecode", "somemessage"),
+			expect: func(t *testing.T, err error) {
+				assert.Error(t, err, clues.ToCore(err))
+			},
+		},
+	}
+	for _, test := range table {
+		suite.Run(test.name, func() {
+			test.expect(suite.T(), api.EvaluateMailboxError(test.err))
+		})
+	}
+}
+
 type UsersIntgSuite struct {
 	tester.Suite
 	its intgTesterSetup
@@ -156,6 +205,20 @@ func (suite *UsersIntgSuite) TestUsers_GetInfo_errors() {
 				assert.NoError(t, err, clues.ToCore(err))
 			},
 		},
+		{
+			name: "mail inbox err - authenticationError",
+			setGocks: func(t *testing.T) {
+				interceptV1Path("users", "user", "drive").
+					Reply(200).
+					JSON(parseableToMap(t, models.NewDrive()))
+				interceptV1Path("users", "user", "mailFolders", "inbox").
+					Reply(400).
+					JSON(parseableToMap(t, odErr(string(graph.AuthenticationError))))
+			},
+			expectErr: func(t *testing.T, err error) {
+				assert.NoError(t, err, clues.ToCore(err))
+			},
+		},
 		{
 			name: "mail inbox err - other error",
 			setGocks: func(t *testing.T) {

src/pkg/services/m365/m365.go

@@ -80,19 +80,13 @@ func UserHasMailbox(ctx context.Context, acct account.Account, userID string) (b
 
 	_, err = ac.Users().GetMailInbox(ctx, userID)
 	if err != nil {
-		// we consider this a non-error case, since it
+		if err := api.EvaluateMailboxError(err); err != nil {
-		// answers the question the caller is asking.
-		if graph.IsErrExchangeMailFolderNotFound(err) {
-			return false, nil
-		}
-
-		if graph.IsErrUserNotFound(err) {
-			return false, clues.Stack(graph.ErrResourceOwnerNotFound, err)
-		}
-
 			return false, clues.Stack(err)
 		}
 
+		return false, nil
+	}
+
 	return true, nil
 }
 

src/pkg/services/m365/m365_test.go

@@ -2,6 +2,7 @@ package m365
 
 import (
 	"context"
+	"fmt"
 	"testing"
 
 	"github.com/alcionai/clues"
@@ -506,6 +507,8 @@ func (suite *DiscoveryIntgSuite) TestGetUserInfo() {
 	}
 	for _, test := range table {
 		suite.Run(test.name, func() {
+			fmt.Printf("\n-----\n%+v\n-----\n", test.name)
+
 			t := suite.T()
 
 			ctx, flush := tester.NewContext(t)