Unable to read data of type Char

[alex-s-gardner]

dc = Zarr.zopen("http://its-live-data.s3.amazonaws.com/test_datacubes/Malaspina_succeeded_ITS_LIVE_vel_EPSG3413_G0120_X-3250000_Y250000.zarr")

numerical data can be read in just fine, e.g.:

dc["mid_date"][:]

character data can not be read in:

dc["sensor_img1"][:]

I do not believe this was an issue with earlier versions of Zarr.jl

#and here's the stack trace:

ERROR: MethodError: no method matching zero(::Type{Char})
Closest candidates are:
  zero(::Union{Type{P}, P}) where P<:Dates.Period at /Applications/Julia-1.8.app/Contents/Resources/julia/share/julia/stdlib/v1.8/Dates/src/periods.jl:53
  zero(::Union{Type{<:Zarr.DateTime64}, Zarr.DateTime64}) at ~/.julia/packages/Zarr/ol3aJ/src/metadata.jl:47
  zero(::Union{Zarr.ASCIIChar, Type{Zarr.ASCIIChar}}) at ~/.julia/packages/Zarr/ol3aJ/src/metadata.jl:22
  ...
Stacktrace:
 [1] _zero(T::Type)
   @ Zarr ~/.julia/packages/Zarr/ol3aJ/src/ZArray.jl:131
 [2] getchunkarray(z::ZArray{Char, 1, Zarr.BloscCompressor, Zarr.ConsolidatedStore{Zarr.HTTPStore}})
   @ Zarr ~/.julia/packages/Zarr/ol3aJ/src/ZArray.jl:135
 [3] readblock!(aout::Vector{Char}, z::ZArray{Char, 1, Zarr.BloscCompressor, Zarr.ConsolidatedStore{Zarr.HTTPStore}}, r::CartesianIndices{1, Tuple{Base.OneTo{Int64}}}; readmode::Bool)
   @ Zarr ~/.julia/packages/Zarr/ol3aJ/src/ZArray.jl:149
 [4] readblock!(aout::Vector{Char}, z::ZArray{Char, 1, Zarr.BloscCompressor, Zarr.ConsolidatedStore{Zarr.HTTPStore}}, r::CartesianIndices{1, Tuple{Base.OneTo{Int64}}})
   @ Zarr ~/.julia/packages/Zarr/ol3aJ/src/ZArray.jl:143
 [5] readblock!(a::ZArray{Char, 1, Zarr.BloscCompressor, Zarr.ConsolidatedStore{Zarr.HTTPStore}}, aout::Vector{Char}, i::Base.OneTo{Int64})
   @ Zarr ~/.julia/packages/Zarr/ol3aJ/src/ZArray.jl:174
 [6] getindex_disk(a::ZArray{Char, 1, Zarr.BloscCompressor, Zarr.ConsolidatedStore{Zarr.HTTPStore}}, i::Function)
   @ DiskArrays ~/.julia/packages/DiskArrays/VGEpq/src/diskarray.jl:31
 [7] getindex(a::ZArray{Char, 1, Zarr.BloscCompressor, Zarr.ConsolidatedStore{Zarr.HTTPStore}}, i::Function)
   @ DiskArrays ~/.julia/packages/DiskArrays/VGEpq/src/diskarray.jl:177
 [8] top-level scope
   @ REPL[127]:1

[meggart]

A quick fix would be to define Zarr._zero(::Type{Char}) = Char(0) before reading from the array. After that you can read the data. The underlying problem here is that the array in question does not define a fill value which makes it hard to initialize the buffer when reading into it. I will also add a patch to master but it might some time until this trickles to the registered version.