"reducing over an empty collection" error in `dotplot`

[yha]

Inputs with small variance sometimes make dotplot error:

x = ones(7)
x[2] -= 1e-16
dotplot(x)

Stacktrace:
  [1] _empty_reduce_error()
    @ Base .\reduce.jl:301
  [2] mapreduce_empty(f::Function, op::Base.BottomRF{typeof(Base._rf_findmin)}, T::Type)
    @ Base .\reduce.jl:344
  [3] reduce_empty(op::Base.MappingRF{Base.var"#262#263"{typeof(identity)}, Base.BottomRF{typeof(Base._rf_findmin)}}, #unused#::Type{Pair{Int64, Float64}})
    @ Base .\reduce.jl:331
  [4] reduce_empty_iter
    @ .\reduce.jl:357 [inlined]
  [5] reduce_empty_iter
    @ .\reduce.jl:356 [inlined]
  [6] foldl_impl
    @ .\reduce.jl:49 [inlined]
  [7] mapfoldl_impl
    @ .\reduce.jl:44 [inlined]
  [8] #mapfoldl#244
    @ .\reduce.jl:162 [inlined]
  [9] mapfoldl
    @ .\reduce.jl:162 [inlined]
 [10] findmin
    @ .\reduce.jl:862 [inlined]
 [11] _findmin
    @ .\reduce.jl:888 [inlined]
 [12] #findmin#783
    @ .\reducedim.jl:1005 [inlined]
 [13] findmin
    @ .\reducedim.jl:1005 [inlined]
 [14] |>
    @ .\operators.jl:966 [inlined]
 [15] _broadcast_getindex_evalf
    @ .\broadcast.jl:670 [inlined]
 [16] _broadcast_getindex
    @ .\broadcast.jl:643 [inlined]
 [17] _getindex
    @ .\broadcast.jl:666 [inlined]
 [18] _broadcast_getindex
    @ .\broadcast.jl:642 [inlined]
 [19] getindex
    @ .\broadcast.jl:597 [inlined]
 [20] macro expansion
    @ .\broadcast.jl:961 [inlined]
 [21] macro expansion
    @ .\simdloop.jl:77 [inlined]
 [22] copyto!
    @ .\broadcast.jl:960 [inlined]
 [23] copyto!
    @ .\broadcast.jl:913 [inlined]
 [24] copy
    @ .\broadcast.jl:885 [inlined]
 [25] materialize(bc::Base.Broadcast.Broadcasted{Base.Broadcast.DefaultArrayStyle{1}, Nothing, typeof(|>), Tuple{Base.Broadcast.Broadcasted{Base.Broadcast.DefaultArrayStyle{1}, Nothing, typeof(|>), Tuple{Vector{Vector{Float64}}, Base.RefValue{typeof(findmin)}}}, Base.RefValue{typeof(first)}}})
    @ Base.Broadcast .\broadcast.jl:860
 [26] (::StatsPlots.var"#getlocalwidths#193")(widths::Vector{Float64}, centers::StepRangeLen{Float64, Base.TwicePrecision{Float64}, Base.TwicePrecision{Float64}, Int64}, y::Vector{Float64})
    @ StatsPlots c:\Users\sternlab\.julia\dev\StatsPlots\src\dotplot.jl:54
 [27] violinoffsets(maxwidth::Float64, y::Vector{Float64})
    @ StatsPlots c:\Users\sternlab\.julia\dev\StatsPlots\src\dotplot.jl:71
 [28] (::StatsPlots.var"#getoffsets#83"{Symbol})(halfwidth::Float64, y::Vector{Float64})
    @ StatsPlots c:\Users\sternlab\.julia\dev\StatsPlots\src\dotplot.jl:19
 [29] macro expansion
    @ c:\Users\sternlab\.julia\dev\StatsPlots\src\dotplot.jl:32 [inlined]
 [30] apply_recipe(plotattributes::AbstractDict{Symbol, Any}, #unused#::Type{Val{:dotplot}}, x::Any, y::Any, z::Any)
    @ StatsPlots C:\Users\sternlab\.julia\packages\RecipesBase\z10lo\src\RecipesBase.jl:300
 [31] _process_seriesrecipe(plt::Any, plotattributes::Any)
    @ RecipesPipeline C:\Users\sternlab\.julia\packages\RecipesPipeline\XxUHt\src\series_recipe.jl:50
 [32] _process_seriesrecipes!(plt::Any, kw_list::Any)
    @ RecipesPipeline C:\Users\sternlab\.julia\packages\RecipesPipeline\XxUHt\src\series_recipe.jl:27
 [33] recipe_pipeline!(plt::Any, plotattributes::Any, args::Any)
    @ RecipesPipeline C:\Users\sternlab\.julia\packages\RecipesPipeline\XxUHt\src\RecipesPipeline.jl:99
 [34] _plot!(plt::Plots.Plot, plotattributes::Any, args::Any)
    @ Plots C:\Users\sternlab\.julia\packages\Plots\io9zQ\src\plot.jl:223