Don't allow inviting existing admins or invitees

backend/private-graph/graph/schema.resolvers.go

@@ -882,6 +882,30 @@ func (r *mutationResolver) SendAdminWorkspaceInvite(ctx context.Context, workspa
 		}
 	}
 
+	// Check if an invite to the email address already exists
+	var existingInvite model.WorkspaceInviteLink
+	if err := r.DB.WithContext(ctx).Where("workspace_id = ? AND invitee_email ILIKE ?", workspaceID, email).First(&existingInvite).Error; err != gorm.ErrRecordNotFound {
+		if err != nil {
+			return nil, e.Wrap(err, "error checking for existing invite link")
+		}
+		return nil, e.Errorf("Looks like \"%s\" has already been invited to join this workspace.", email)
+	}
+
+	// Check if the email is already assigned to an admin in the workspace
+	var existingAdmin model.Admin
+	if err := r.DB.WithContext(ctx).Where("email ILIKE ?", email).First(&existingAdmin).Error; err != gorm.ErrRecordNotFound {
+		if err != nil {
+			return nil, e.Wrap(err, "error checking for existing admin")
+		}
+		var workspaceAdmin model.WorkspaceAdmin
+		if err := r.DB.WithContext(ctx).Where("admin_id = ? AND workspace_id = ?", existingAdmin.ID, workspaceID).First(&workspaceAdmin).Error; err != gorm.ErrRecordNotFound {
+			if err != nil {
+				return nil, e.Wrap(err, "error checking for existing admin in workspace")
+			}
+			return nil, e.Errorf("Looks like \"%s\" is already an admin in this workspace.", email)
+		}
+	}
+
 	inviteLink := r.CreateInviteLink(workspaceID, &email, role, false)
 
 	if err := r.DB.WithContext(ctx).Create(inviteLink).Error; err != nil {

frontend/src/pages/WorkspaceTeam/components/InviteMemberModal.tsx

@@ -46,8 +46,15 @@ function InviteMemberModal({
 
 	const [
 		sendInviteEmail,
-		{ loading: sendLoading, data: sendInviteEmailData, reset: sendReset },
-	] = useSendAdminWorkspaceInviteMutation()
+		{
+			loading: sendLoading,
+			data: sendData,
+			error: sendError,
+			reset: sendReset,
+		},
+	] = useSendAdminWorkspaceInviteMutation({
+		fetchPolicy: 'no-cache',
+	})
 
 	const onSubmit = (e: { preventDefault: () => void }) => {
 		e.preventDefault()
@@ -143,7 +150,7 @@ function InviteMemberModal({
 					</Button>
 				</div>
 			</form>
-			{sendInviteEmailData?.sendAdminWorkspaceInvite && (
+			{sendData?.sendAdminWorkspaceInvite && (
 				<Alert
 					shouldAlwaysShow
 					trackingId="InviteAdminToWorkspaceConfirmation"
@@ -154,9 +161,7 @@ function InviteMemberModal({
 							You can also share with them this link:{' '}
 							<span>
 								<CopyText
-									text={
-										sendInviteEmailData.sendAdminWorkspaceInvite
-									}
+									text={sendData.sendAdminWorkspaceInvite}
 									onCopyTooltipText="Copied invite link to clipboard!"
 									inline
 								/>
@@ -165,6 +170,15 @@ function InviteMemberModal({
 					}
 				/>
 			)}
+			{sendError && (
+				<Alert
+					shouldAlwaysShow
+					trackingId="InviteAdminToWorkspaceError"
+					message="Couldn't send workspace invite"
+					type="error"
+					description={sendError.message}
+				/>
+			)}
 			<hr className={styles.hr} />
 			<p className={styles.boxSubTitle}>
 				Or share this link with them (this link expires{' '}