Reject transformations on SubDataFrame with copycols=false

Author: arkgupta17

src/abstractdataframe/selection.jl

@@ -1823,12 +1823,26 @@ function manipulate(dfv::SubDataFrame, @nospecialize(args...); copycols::Bool, k
         newinds = Any[]
         seen_single_column = Set{Int}()
         for ind in args
+<<<<<<< HEAD
            if ind isa Pair || ind isa AbstractVecOrMat{<:Pair}
               throw(ArgumentError(
                 "Transformations are not supported for SubDataFrame with copycols=false. " *
                 "Only column selection is allowed."
               ))
            end
+=======
+            if ind isa ColumnIndex
+               if ind_idx in seen_single_column
+                   throw(ArgumentError(
+                       "selecting the same column multiple times " *
+                       "using Symbol, string or integer is not allowed " *
+                       "($ind was passed more than once)"
+                   ))
+                end
+             end
+           
+           
+>>>>>>> 8c73674e (Reject transformations on SubDataFrame with copycols=false)
            ind_idx = index(dfv)[ind]
 
            if ind isa ColumnIndex

test/utils.jl

@@ -196,3 +196,9 @@ end
     @test parent(res.a) === parent(v.a)
     @test parent(res.b) === parent(v.b)
 end
+<<<<<<< HEAD
+=======
+
+
+
+>>>>>>> 8c73674e (Reject transformations on SubDataFrame with copycols=false)