Ah, shoot. I fell back to by base environment when making the MWE. My real code ran in an environment that uses CSV v0.7.4. Here’s the stacktrace from my real code:
ERROR: UndefRefError: access to undefined reference
Stacktrace:
[1] getindex at ./array.jl:787 [inlined]
[2] index at /Users/bieganek/.julia/packages/SentinelArrays/zmvEI/src/chainedvector.jl:33 [inlined]
[3] deleteat! at /Users/bieganek/.julia/packages/SentinelArrays/zmvEI/src/chainedvector.jl:144 [inlined]
[4] deleteat!(::SentinelArrays.SentinelArray{String,1,UndefInitializer,Missing,SentinelArrays.ChainedVector{String,Array{String,1}}}, ::Int64) at /Users/bieganek/.julia/packages/SentinelArrays/zmvEI/src/SentinelArrays.jl:279
[5] deleteat!(::SentinelArrays.SentinelArray{String,1,UndefInitializer,Missing,SentinelArrays.ChainedVector{String,Array{String,1}}}, ::Array{Int64,1}) at /Users/bieganek/.julia/packages/SentinelArrays/zmvEI/src/SentinelArrays.jl:291
[6] (::DataFrames.var"#161#162"{Array{Int64,1}})(::SentinelArrays.SentinelArray{String,1,UndefInitializer,Missing,SentinelArrays.ChainedVector{String,Array{String,1}}}) at /Users/bieganek/.julia/packages/DataFrames/htZzm/src/dataframe/dataframe.jl:873
[7] foreach(::DataFrames.var"#161#162"{Array{Int64,1}}, ::Array{AbstractArray{T,1} where T,1}) at ./abstractarray.jl:1919
[8] delete!(::DataFrame, ::Array{Int64,1}) at /Users/bieganek/.julia/packages/DataFrames/htZzm/src/dataframe/dataframe.jl:873
[9] _filter!_helper(::DataFrame, ::Function, ::DataFrames.DataFrameRows{DataFrame,DataFrames.Index}) at /Users/bieganek/.julia/packages/DataFrames/htZzm/src/abstractdataframe/abstractdataframe.jl:1075
[10] filter! at /Users/bieganek/.julia/packages/DataFrames/htZzm/src/abstractdataframe/abstractdataframe.jl:1056 [inlined]
[11] process_child_file(::StateChildFile, ::String, ::Dict{Tuple{String,String,String,Date},Int64}) at /Users/bieganek/projects/NCANDS/NCANDS.jl/src/preprocess.jl:393
[12] top-level scope at REPL[20]:1