From 2d8299ad7977bcfb597afcb4d7770c6f03f1a7a6 Mon Sep 17 00:00:00 2001
From: Michal Stolarczyk <stolarczyk.michal93@gmail.com>
Date: Mon, 16 Mar 2020 13:48:32 -0400
Subject: [PATCH] do not append if attr already exists

---
 R/project.R | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/R/project.R b/R/project.R
index 7f8cf1dc..07fbfbb2 100644
--- a/R/project.R
+++ b/R/project.R
@@ -303,9 +303,12 @@ setMethod(
         for (iConst in seq_along(constants)) {
             # create a one column data.table and glue appand it with to the 
             # current samples data.table
-            constantCol = data.table::data.table(rep(constants[[iConst]], colLen))
-            names(constantCol) = constantsNames[iConst]
-            .Object@samples = cbind(.Object@samples, constantCol)
+            if(!constantsNames[iConst] %in% colnames(sampleTable(.Object))) {
+                constantCol = 
+                    data.table::data.table(rep(constants[[iConst]], colLen))
+                names(constantCol) = constantsNames[iConst]
+                .Object@samples = cbind(.Object@samples, constantCol)
+            }
         }
     }
     return(.Object)