Return a Rich object instead of Dict for show_richest

[rikhuijzer]

I was trying to reduce the TTFX for SessionActions.open and ended up in PlutoRunner again.

With this PR, show_richest will now always return a Rich object instead of a Dict. This improves readability and also makes the compiler a bit happier. It reduces allocations from ~90 MB to ~80 MB on the TTFX benchmark of #2117 on @btime it reduces time by 17 μs (wow wow). Anyway, the main argument for this PR is code readability.

[github-actions]

Try this Pull Request!

Open Julia and type:

julia> import Pkg
julia> Pkg.activate(temp=true)
julia> Pkg.add(url="https://github.com/fonsp/Pluto.jl", rev="rh/rich-struct")
julia> using Pluto

[rikhuijzer]

@fonsp, do you know where the following error is coming from?

cell.output.body = Dict{Symbol, Any}(
  :msg => "TaskFailedException\n\n    nested task error: could not compute non-nothing type\n    Stacktrace:\n      
    [1] error(s::String)\n        @ Base ./error.jl:35\n      
    [2] nonnothingtype_checked(T::Type)\n        @ Base ./some.jl:31\n      
    [3] convert(#unused#::Type{Union{Nothing, String, Dict, Vector{UInt8}, var\"#s119\"} where var\"#s119\"<:Pluto.PlutoRunner.Rich}, x::Main.PlutoRunner.RichObject)\n        @ Base ./some.jl:36\n      
    [4] Pluto.CellOutput(body::Main.PlutoRunner.RichObject, mime::MIME{Symbol(\"application/vnd.pluto.tree+object\")}, rootassignee::Symbol, last_run_timestamp::Float64, persist_js_state::Bool, has_pluto_hook_features::Bool)\n        @ Pluto ~/git/Pluto.jl/src/notebook/Cell.jl:12\n      
    [5] Pluto.CellOutput(; body::Main.PlutoRunner.RichObject, mime::MIME{Symbol(\"application/vnd.pluto.tree+object\")}, rootassignee::Symbol, last_run_timestamp::Float64, persist_js_state::Bool, has_pluto_hook_features::Bool)\n        @ Pluto ./util.jl:493\n      
    [6] set_output!(cell::Pluto.Cell, run::NamedTuple{(:output_formatted, :errored, :interrupted, :process_exited, :runtime, :published_objects, :has_pluto_hook_features), Tuple{Union{Tuple, Main.PlutoRunner.MimedOutput}, Bool, Bool, Bool, Union{Nothing, UInt64}, Dict{String, Any}, Bool}}, expr_cache::Pluto.ExprAnalysisCache; persist_js_state::Bool)\n        @ Pluto ~/git/Pluto.jl/src/evaluation/Run.jl:312\n      
    [7] run_single!(session_notebook::Tuple{Pluto.ServerSession, Pluto.Notebook}, cell::Pluto.Cell, reactive_node::Pluto.ReactiveNode, expr_cache::Pluto.ExprAnalysisCache; user_requested_run::Bool, capture_stdout::Bool)\n        @ Pluto ~/git/Pluto.jl/src/evaluation/Run.jl:290\n      
    [8] run_reactive_core!(session::Pluto.ServerSession, notebook::Pluto.Notebook, old_topology::Pluto.NotebookTopology, new_topology::Pluto.NotebookTopology, roots::Vector{Pluto.Cell}; deletion_hook::typeof(Pluto.WorkspaceManager.move_vars), user_requested_run::Bool, already_run::Vector{Pluto.Cell}, bond_value_pairs::Base.Iterators.Zip{Tuple{Vector{Symbol}, Vector{Any}}})\n        @ Pluto ~/git/Pluto.jl/src/evaluation/Run.jl:178\n      
    [9] run_reactive_core!\n        @ ~/git/Pluto.jl/src/evaluation/Run.jl:61 [inlined]\n     
    [10] (::Pluto.var\"#255#259\"{Bool, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, Pluto.ServerSession, Pluto.Notebook})()\n        @ Pluto ~/git/Pluto.jl/src/evaluation/Run.jl:597\n     
    [11] withtoken(f::Pluto.var\"#255#259\"{Bool, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, Pluto.ServerSession, Pluto.Notebook}, token::Pluto.Token)\n        @ Pluto ~/git/Pluto.jl/src/evaluation/Tokens.jl:19\n     
    [12] #254\n        @ ~/git/Pluto.jl/src/evaluation/Run.jl:593 [inlined]\n     
    [13] macro expansion\n        @ ~/git/Pluto.jl/src/evaluation/Tokens.jl:58 [inlined]\n     
    [14] (::Pluto.var\"#225#226\"{Pluto.var\"#254#258\"{Bool, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, Pluto.ServerSession, Pluto.Notebook}})()\n        @ Pluto ./task.jl:482", :stacktrace => Dict{Symbol, Any}[Dict(:call => "wait", :inlined => true, :file => "task.jl", :line => 345, :path => "./task.jl"), Dict(:call => "fetch", :inlined => true, :file => "task.jl", :line => 360, :path => "./task.jl"), Dict(:call => "maybe_async(::Pluto.var\"#254#258\"{Bool, Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, Pluto.ServerSession, Pluto.Notebook}, ::Bool)", :inlined => false, :file => "Run.jl", :line => 247, :path => "/home/rik/git/Pluto.jl/src/evaluation/Run.jl"), Dict(:call => "var\"#update_save_run!#251\"(::Bool, ::Bool, ::Bool, ::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}, ::typeof(Pluto.update_save_run!), ::Pluto.ServerSession, ::Pluto.Notebook, ::Vector{Pluto.Cell})", :inlined => false, :file => "Run.jl", :line => 592, :path => "/home/rik/git/Pluto.jl/src/evaluation/Run.jl"), Dict(:call => "var\"#open#2\"(::Bool, ::Nothing, ::Bool, ::Base.UUID, ::typeof(Pluto.SessionActions.open), ::Pluto.ServerSession, ::String)", :inlined => false, :file => "SessionActions.jl", :line => 73, :path => "/home/rik/git/Pluto.jl/src/webserver/SessionActions.jl"), Dict(:call => "top-level scope", :inlined => true, :file => "Surprising revelation 3.jl#==#83d63f92-df6f-11ec-2ffc-f55f0d0092e5", :line => 1, :path => "/home/rik/.julia/pluto_notebooks/Surprising revelation 3.jl#==#83d63f92-df6f-11ec-2ffc-f55f0d0092e5")])

EDIT: Ah nevermind. This is Main.PlutoRunner.RichObject != Pluto.PlutoRunner.RichObject because of distributed.
EDIT2: Asked question at https://discourse.julialang.org/t/pass-struct-from-module-to-distributed-worker/81905.
EDIT3: This PR could possibly be fixed by #1881 since that could solve Pluto.PlutoRunner.Rich != Main.PlutoRunner.Rich.

[fonsp]

I should have documented this somewhere 😭, but I have been purposefully restricting the communication between the Pluto runner and the Pluto server to Base Julia types only, to avoid difficult serialization problems. This will also make the transition to our own Distributed easier.

[rikhuijzer]

I should have documented this somewhere 😭

No problem. It was a good learning experience 👍

[fonsp]

997f313 :)