Add Compiler flag to specify --code-coverage

[disberd]

This PR adds two compiler flags to specify how to track code coverage in the notebook session.

I created two distinct flags as the command line option --code-coverage can be provided 2 times:

• One for specifying a file where to store the coverage data.
  • By default, if coverage is tracked, a separate coverage file per source file is generated. Specifying a file explicitly saves everything in a single file.
• Another for specifying what to track, it can be none, user, all or @<path> for a specific path.

The --code-coverage=@<path> was added in 1.8.

I mention this in the docstring but I do not do validation of the content of the provided inputs to the flag as that is not done for other compiler flags.

Fixes #2818

[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/disberd/Pluto.jl", rev="code_coverage_flag")
julia> using Pluto

[disberd]

I guess fails on julia nightly are not related to this PR

[fonsp]

Thanks! Looks good, it's pretty weird API but that's because the --code-coverage API is weird 🙃

I'm not sure about the tests, I feel like this is more a test of Julia's internals, and less of Pluto's wrapper around it. It also launches a couple processes in sequence which makes the tests longer.

Maybe you could write a test that is closer to the way you intend to use it, and tests that it produces the result that you want? I tried this:

julia> options = Pluto.Configuration.from_flat_kwargs(; launch_browser=false, code_coverage_file="test.info", code_coverage_track="all");

julia> 🍭 = Pluto.ServerSession(; options);

julia> testfile = download(
           "https://raw.githubusercontent.com/fonsp/Pluto.jl/main/sample/Tower%20of%20Hanoi.jl",
       )
"/var/folders/v_/fhpj9jn151d4p9c2fdw2gv780000gn/T/jl_gBkxuXU1Sb"

julia> nb = Pluto.SessionActions.open(🍭, testfile; run_async=false);

julia> contents = read("test.info", String)
"SF:/Users/julia/.julia/scratchspaces/a66863c6-20e8-4ff4-8a62-49f30b1f605e/agent-cache/default-honeycrisp-HL2F7YQ3XH.0/build/default-honeycrisp-HL2F7YQ3XH-0/julialang/julia-release-1-dot-10/usr/share/julia/stdlib/v1.10/Pkg/src/utils.jl\nDA:2,3\nDA:3,1\nDA:4,1\nDA:5,1\nDA:6,1\n" ⋯ 22634 bytes ⋯ ",0\nDA:456,0\nDA:458,0\nDA:459,0\nDA:460,0\nDA:461,0\nDA:462,0\nDA:463,0\nDA:465,0\nDA:517,0\nDA:519,389\nDA:538,2\nDA:540,0\nDA:541,0\nDA:542,0\nDA:543,0\nDA:574,4\nDA:575,0\nDA:576,394\nDA:579,0\nDA:642,199\nDA:645,24\nDA:884,0\nDA:885,0\nDA:886,0\nDA:887,0\nDA:889,0\nLH:9\nLF:35\nend_of_record\n"

julia> fn = basename(testfile)
"jl_gBkxuXU1Sb"

julia> occursin(fn, contents)
false

julia> # weird

This actually looks like the notebook file is not included in the coverage...

[disberd]

@fonsp Yeah your comment makes sense, I changed the tests to only do a single test to verify that a coverage file is created for some package under development (I used Example.jl as example :D).

I also noticed in my tests that code coverage for code touched by a notebook is only generated after closing the workspace_session, which might be why in your test you couldn't see the notebook lines.

[disberd]

Not sure why this fails on macos 1.10 and I do not have a Mac to debug :(

[fonsp]

what to do with this pr? for me its a lot of work for a feature that i dont imagine using :o but it would be nice to have

[disberd]

If I get access to a Mac I can try fixing it, (1.11 test breaks do not seem to happen in the code touched by this), but doing that just relying on CI is indeed a lot of work.