Julia 1.13: re-wrap @doc cell result as Docs.Binding

[pankgeorg]

Summary

Restore the docstring-as-cell-output rendering on Julia 1.13+ that was broken by JuliaLang/julia#59882. Fixes the failing assertions in #3449; part of the #3389 umbrella. Continues — but does not stack on — the closed #3452, which had been abandoned because the author could not pin down the upstream behavior change.

What changed in Julia 1.13

Same parsed expression, different result:

julia> Meta.parse("\"::Bool\"\nf(::Bool) = 1") |> e -> Core.eval(Main, e) |> typeof
# 1.12: Base.Docs.Binding
# 1.13: typeof(f)

@doc str def now returns the value of def instead of a Base.Docs.Binding (JuliaLang/julia#60681, closed as not planned). Pluto's format_output(::Base.Docs.Binding) dispatch no longer fires, so documented function cells render as f (generic function with N methods) rather than the docstring HTML.

Docs.doc(binding) itself still works correctly on 1.13 and aggregates all method docstrings as before — only the cell result type changed.

The fix

Detect the (pre-macroexpansion) @doc macrocall in run_expression, extract the bound name from the definition, and re-wrap the result as Docs.Binding(workspace, name) before storing in cell_results. This puts the cell back on the existing rendering path; no display-side changes required.

• No-op on Julia < 1.13 (where the result is already a Docs.Binding).
• Skipped for CapturedException results so error rendering is untouched.
• Skipped if the bound name isn't defined in the workspace, so a half-failed definition still falls through to the default formatter.
• Handles common doc targets: f(x) = …, function f end, f(::T) where T, parametric methods, struct, macro, module, const.

Test plan

• CI: test/MacroAnalysis.jl "Doc strings" testset (the 11 failing assertions from Julia 1.13 tests: Macro analysis - docstrings #3449) passes on Julia 1.13.
• CI: same testset still passes on 1.11 and 1.12 (helper is a no-op).
• Manual: open a notebook on 1.13, run a cell like "docstring"\nf(::Bool) = 1, verify the rich docstring panel renders.
• Manual: redefine a method in another cell, verify both method docstrings appear in either cell's output.

Out of scope (follow-ups from #3389)

• warn_julia_compat() in src/Pluto.jl still warns on 1.13 — should be bumped to 1.14 once the testset is green.
• Malt.jl#101 and #93 (1.13 interrupt failures) are still open.
• GracefulPkg.jl 1.13 audit per the umbrella issue.

Try this Pull Request!

Open Julia and type:

julia> import Pkg
julia> Pkg.activate(temp=true)
julia> Pkg.add(url="https://github.com/JuliaPluto/Pluto.jl", rev="pg/julia-1.13-docstring-display")
julia> using Pluto

[pankgeorg]

Another idea:

• Make a pluto-specific show method for Functions that always gets the latest docs (after reactivity is done rendering)
  • in order to get the function to display the "same" docstring across methods, and not different, based on the timing of its execution
• Make that work in the pre - 1.12
• Keep the docs renderer in case someone actually explicitly requests it.

[fonsp]

Little nsippet

<div style="
font-family: JuliaMono;
padding: .4em .4em;
font-size: .8rem;
">

<span style='font-style: italic; opacity: .8;'>function</span>

<span style='font-weight: bold;'>hello_world</span>

<a style='
	font-family: system-ui;
margin-inline-start: 2ch;
' href="#">(View docs)</a>

</div>