MethodError when trying to show created Signal in Pluto

[notthetup]

Running a simple Pluto notebook with

using SignalAnalysis, SignalAnalysis.Units
---------
chirp(5kHz, 7kHz, 100ms, 44.1kHz; shape=:hyperbolic, window=(tukey,0.05))

gives this...

Failed to show value:

MethodError: no method matching keys(::SignalAnalysis.SamplingInfo)

Closest candidates are:

keys(!Matched::Missings.EachFailMissing) at /Users/chinmay/.julia/packages/Missings/sx5js/src/Missings.jl:154

keys(!Matched::DataStructures.Trie) at /Users/chinmay/.julia/packages/DataStructures/ixwFs/src/trie.jl:82

keys(!Matched::DataStructures.Trie, !Matched::AbstractString) at /Users/chinmay/.julia/packages/DataStructures/ixwFs/src/trie.jl:82

...

showarg(::IOBuffer, ::MetaArrays.MetaArray{Vector{ComplexF64}, SignalAnalysis.SamplingInfo, ComplexF64, 1}, ::Bool)@MetaArrays.jl:118
var"#sprint#385"(::Nothing, ::Int64, ::typeof(sprint), ::Function, ::MetaArrays.MetaArray{Vector{ComplexF64}, SignalAnalysis.SamplingInfo, ComplexF64, 1}, ::Vararg{Any, N} where N)@io.jl:105
sprint(::Function, ::MetaArrays.MetaArray{Vector{ComplexF64}, SignalAnalysis.SamplingInfo, ComplexF64, 1}, ::Vararg{Any, N} where N)@io.jl:101
array_prefix(::Any)@PlutoRunner.jl:703
tree_data(::AbstractVector{var"#s84"} where var"#s84", ::IOContext{IOBuffer})@PlutoRunner.jl:785
show_richest(::IOContext{IOBuffer}, ::Any)@PlutoRunner.jl:639
var"#sprint_withreturned#28"(::IOContext{Base.DevNull}, ::Int64, ::typeof(Main.PlutoRunner.sprint_withreturned), ::Function, ::MetaArrays.MetaArray{Vector{ComplexF64}, SignalAnalysis.SamplingInfo, ComplexF64, 1})@PlutoRunner.jl:591
format_output_default(::Any, ::Any)@PlutoRunner.jl:515
#format_output#17@PlutoRunner.jl:532[inlined]
formatted_result_of(::Base.UUID, ::Bool, ::Nothing, ::Module)@PlutoRunner.jl:448
top-level scope@none:1

[mchitre]

No problem on REPL:

julia> using SignalAnalysis, SignalAnalysis.Units

julia> chirp(5kHz, 7kHz, 100ms, 44.1kHz; shape=:hyperbolic, window=(tukey,0.05))
SampledSignal @ 44100.0 Hz, 4410-element Vector{ComplexF64}:
                    0.0 - 0.0im
 0.00015368365272524137 + 0.0001327388027281813im
 0.00011810536015839258 + 0.0008034894213194122im
  -0.000980410986611016 + 0.0015412581539023496im
  -0.003108732228055483 + 0.0009334648998984505im
              :

[mchitre]

Confirmed error occurs as reported with Pluto. The reason is that Pluto calls Base.showarg(), which the MetaArrays package defines and calls Base.keys() on the meta data object, implicitly assuming that the object stored in meta data is a dictionary! The SignalAnalysis' metadata is stored in a struct SignalInfo, for which Base.keys() is not defined.

Simple fix: Base.keys(x::SignalAnalysis.SamplingInfo) = fieldnames(typeof(x))

[mchitre]

Works!