"workspaces" break serialization

[aplavin]

I'm trying to persist some structs between restarts of a notebook, but this doesn't work due to workspaceXXX being prepended to each module name.

A simple example follows.

1. Create notebook with these four cells:

using Serialization

# for some reason M is actually named Main.workspace5.M in Pluto
# regular Julia REPL gives just Main.M
module M
struct S end
end

serialize("/tmp/s.ser", M.S())

deserialize("/tmp/s.ser")

Everything works fine here.
2. Remove the serialize(...) cell.
3. Restart the notebook.
4. The M module is now named Main.workspace13.M. Correspondingly, deserialize() fails with UndefVarError: workspace5 not defined error.

How to fix this error for now?

[MichaelHatherly]

@dralletje and I were discussing this one yesterday. It's a bit unfortunate that Serialization doesn't "just work" out of the box, but he did convince me it was necessary, so I've put together https://github.com/MichaelHatherly/PlutoSerialization.jl which handles finding the correct definitions within the workspaces during deserialization so that you can persist data between sessions in a more reproducible way. If it breaks or has any bugs please open an issue over in that repo.

[schlichtanders]

Now as Pluto supports the use of Distributed via Malt.jl, this issue appears again.

A simple remote call like

remotecall_fetch(() -> readchomp(`hostname`), pid) 

already gives the error like

UndefVarError: `workspace#72` not defined

I opened an issue on julialang/julia for this JuliaLang/Distributed.jl#1