Fetch folder by display name

src/internal/connector/exchange/api/contacts.go

@@ -55,6 +55,41 @@ func (c Contacts) CreateContactFolder(
 	return mdl, nil
 }
 
+// GetContactFolderByDisplayName fetches contact folder which has the displayName of
+// folderName. This is only done at root level.
+func (c Contacts) GetContactFolderByDisplayName(
+	ctx context.Context,
+	user, folderName string,
+) (models.ContactFolderable, error) {
+	filter := fmt.Sprintf("displayName eq '%s'", folderName)
+	options := &users.ItemContactFoldersRequestBuilderGetRequestConfiguration{
+		QueryParameters: &users.ItemContactFoldersRequestBuilderGetQueryParameters{
+			Filter: &filter,
+		},
+	}
+
+	resp, err := c.Stable.Client().UsersById(user).ContactFolders().Get(ctx, options)
+	if err != nil {
+		return nil, graph.Wrap(ctx, err, "getting contact folder").
+			With("folder name", folderName)
+	}
+
+	// We only expect one folder with provided folderName. Return an error if
+	// multiple folders exist(unlikely) or if no folder was found
+	if len(resp.GetValue()) != 1 {
+		return nil, graph.Wrap(ctx, err, "unexpected number of folders").
+			With("folder count", len(resp.GetValue())).
+			With("folder name", folderName)
+	}
+
+	fold := resp.GetValue()[0]
+	if err := checkIDAndName(fold); err != nil {
+		return nil, err
+	}
+
+	return fold, nil
+}
+
 // DeleteContainer deletes the ContactFolder associated with the M365 ID if permissions are valid.
 func (c Contacts) DeleteContainer(
 	ctx context.Context,

src/internal/connector/exchange/service_restore.go

@@ -651,19 +651,27 @@ func establishContactsRestoreLocation(
 
 	ctx = clues.Add(ctx, "is_new_cache", isNewCache)
 
-	temp, err := ac.Contacts().CreateContactFolder(ctx, user, folders[0])
-	if err != nil {
+	fold, err := ac.Contacts().CreateContactFolder(ctx, user, folders[0])
+	// 409 handling: Fetch folder if it exists.
+	// This is rare, but it may happen if an earlier CreateContactFolder POST failed
+	// with 5xx, potentially leaving dirty state in graph.
+	if graph.IsErrFolderExists(err) {
+		fold, err = ac.Contacts().GetContactFolderByDisplayName(ctx, user, folders[0])
+		if err != nil {
+			return "", err
+		}
+	} else if err != nil {
 		return "", err
 	}
 
-	folderID := ptr.Val(temp.GetId())
+	folderID := ptr.Val(fold.GetId())
 
 	if isNewCache {
 		if err := cfc.Populate(ctx, errs, folderID, folders[0]); err != nil {
 			return "", clues.Wrap(err, "populating contact cache")
 		}
 
-		if err = cfc.AddToCache(ctx, temp); err != nil {
+		if err = cfc.AddToCache(ctx, fold); err != nil {
 			return "", clues.Wrap(err, "adding contact folder to cache")
 		}
 	}

src/internal/connector/graph/errors.go

@@ -41,6 +41,7 @@ const (
 	syncFolderNotFound          errorCode = "ErrorSyncFolderNotFound"
 	syncStateInvalid            errorCode = "SyncStateInvalid"
 	syncStateNotFound           errorCode = "SyncStateNotFound"
+	folderExists                errorCode = "ErrorFolderExists"
 )
 
 const (
@@ -172,6 +173,10 @@ func IsMalwareResp(ctx context.Context, resp *http.Response) bool {
 	return false
 }
 
+func IsErrFolderExists(err error) bool {
+	return hasErrorCode(err, folderExists)
+}
+
 // ---------------------------------------------------------------------------
 // error parsers
 // ---------------------------------------------------------------------------