minor errs cleanup (#3234)

some code cleanup that happened while investigating a bug repro

---

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

- [x] ⛔ No

#### Type of change

- [x] 🧹 Tech Debt/Cleanup

#### Test Plan

- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/connector/discovery/discovery.go

@@ -93,7 +93,7 @@ func User(
 	u, err := gwi.GetByID(ctx, userID)
 	if err != nil {
 		if graph.IsErrUserNotFound(err) {
-			return nil, nil, clues.Stack(graph.ErrResourceOwnerNotFound).With("user_id", userID)
+			return nil, nil, clues.Stack(graph.ErrResourceOwnerNotFound, err).With("user_id", userID)
 		}
 
 		return nil, nil, clues.Wrap(err, "getting user")

src/pkg/errs/errs.go

@@ -37,13 +37,13 @@ func Internal(enum errEnum) []error {
 // Is checks if the provided error contains an internal error that matches
 // the public error category.
 func Is(err error, enum errEnum) bool {
-	esl, ok := internalToExternal[enum]
+	internalErrs, ok := internalToExternal[enum]
 	if !ok {
 		return false
 	}
 
-	for _, e := range esl {
-		if errors.Is(err, e) {
+	for _, target := range internalErrs {
+		if errors.Is(err, target) {
 			return true
 		}
 	}

src/pkg/errs/errs_test.go

@@ -3,6 +3,7 @@ package errs
 import (
 	"testing"
 
+	"github.com/alcionai/clues"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
 
@@ -38,8 +39,8 @@ func (suite *ErrUnitSuite) TestInternal() {
 
 func (suite *ErrUnitSuite) TestIs() {
 	table := []struct {
-		is    errEnum
-		input error
+		target errEnum
+		err    error
 	}{
 		{RepoAlreadyExists, repository.ErrorRepoAlreadyExists},
 		{BackupNotFound, repository.ErrorBackupNotFound},
@@ -47,9 +48,24 @@ func (suite *ErrUnitSuite) TestIs() {
 		{ResourceOwnerNotFound, graph.ErrResourceOwnerNotFound},
 	}
 	for _, test := range table {
-		suite.Run(string(test.is), func() {
-			assert.True(suite.T(), Is(test.input, test.is))
-			assert.False(suite.T(), Is(assert.AnError, test.is))
+		suite.Run(string(test.target), func() {
+			var (
+				w  = clues.Wrap(test.err, "wrap")
+				s  = clues.Stack(test.err)
+				es = clues.Stack(assert.AnError, test.err)
+				se = clues.Stack(test.err, assert.AnError)
+				sw = clues.Stack(assert.AnError, w)
+				ws = clues.Stack(w, assert.AnError)
+			)
+
+			assert.True(suite.T(), Is(test.err, test.target))
+			assert.True(suite.T(), Is(w, test.target))
+			assert.True(suite.T(), Is(s, test.target))
+			assert.True(suite.T(), Is(es, test.target))
+			assert.True(suite.T(), Is(se, test.target))
+			assert.True(suite.T(), Is(sw, test.target))
+			assert.True(suite.T(), Is(ws, test.target))
+			assert.False(suite.T(), Is(assert.AnError, test.target))
 		})
 	}
 }

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

@@ -263,7 +263,7 @@ func (c Users) GetInfo(ctx context.Context, userID string) (*UserInfo, error) {
 	if _, err := c.GetMailFolders(ctx, userID, options); err != nil {
 		if graph.IsErrUserNotFound(err) {
 			logger.CtxErr(ctx, err).Error("user not found")
-			return nil, err
+			return nil, graph.Stack(ctx, clues.Stack(graph.ErrResourceOwnerNotFound, err))
 		}
 
 		if !graph.IsErrExchangeMailFolderNotFound(err) ||