New heuristic to skip intermediate bond values

[fonsp]

Fix #1891, see that issue for the introduction

Example 1

Schermopname.2022-02-03.om.17.15.37.mov

Example 2

Schermopname.2022-02-03.om.17.14.42.mov

Cause of problem

Before this PR, we would hold back all intermediate bond updates while this function returns true:

Pluto.jl/frontend/components/Editor.js

Lines 786 to 795 in d8bf859

	this.notebook_is_idle = () => {
	return !(
	this.pending_local_updates > 0 ||
	// a cell is running:
	Object.values(this.state.notebook.cell_results).some((cell) => cell.running || cell.queued) ||
	// a cell is initializing JS:
	!_.isEmpty(this.js_init_set) ||
	!this.is_process_ready()
	)
	}

In particular, we check that no cells are running or queued (Object.values(this.state.notebook.cell_results).some((cell) => cell.running || cell.queued)).

The problem is that it takes some time for the server to process the bond values, which will set the cell statuses to "queued" (in an async task). In the short time window after sending a bond value, but before a response from the server, notebook_is_idle() will always return true, and all bond updates start queueing in the server.

Solution

This PR adds a new heuristic, waiting_for_bond_to_trigger_execution. Whenever you ask the server to run a bond value, it is set to true immediately, and only set back to false after a patch response from the server (which will likely be a response from the bond request).

Before setting waiting_for_bond_to_trigger_execution to true, we check whether any (enabled) cell depends on the bound symbol.

TODO

• (note to self) We might not need the frontend dependency stuff anymore bc the backend is always sending a patch after a bond request...

[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="waiting_for_bond_to_trigger_execution")
julia> using Pluto