Pkg.upgrade_manifest broke my Manifest

[vtjnash]

julia> using Pkg; Pkg.upgrade_manifest()
     Updated Format of manifest file at `/home/vtjnash/.julia/environments/v1.1/Manifest.toml` updated from v1.0 to v2.0

(@v1.1) pkg> up
ERROR: ArgumentError: invalid version string: nothing
Stacktrace:
  [1] parse
    @ ./version.jl:126 [inlined]
  [2] VersionNumber(v::String)
    @ Base ./version.jl:130
  [3] Pkg.Types.Manifest(raw::Dict{String, Any}, f_or_io::String)
    @ Pkg.Types /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/manifest.jl:134
  [4] read_manifest(f_or_io::String)
    @ Pkg.Types /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/manifest.jl:198
  [5] Pkg.Types.EnvCache(env::Nothing)
    @ Pkg.Types /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/Types.jl:338
  [6] EnvCache
    @ /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/Types.jl:317 [inlined]
  [7] Pkg.Types.Context()
    @ Pkg.Types ./util.jl:471
  [8] up(pkgs::Vector{Pkg.Types.PackageSpec}; io::Base.TTY, kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Pkg.API /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/API.jl:145
  [9] up(pkgs::Vector{Pkg.Types.PackageSpec})
    @ Pkg.API /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/API.jl:144
 [10] do_cmd!(command::Pkg.REPLMode.Command, repl::REPL.LineEditREPL)
    @ Pkg.REPLMode /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/REPLMode/REPLMode.jl:407
 [11] do_cmd(repl::REPL.LineEditREPL, input::String; do_rethrow::Bool)
    @ Pkg.REPLMode /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/REPLMode/REPLMode.jl:385
 [12] do_cmd
    @ /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/REPLMode/REPLMode.jl:376 [inlined]
 [13] (::Pkg.REPLMode.var"#24#27"{REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::IOBuffer, ok::Bool)
    @ Pkg.REPLMode /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/REPLMode/REPLMode.jl:549
 [14] #invokelatest#2
    @ ./essentials.jl:716 [inlined]
 [15] invokelatest
    @ ./essentials.jl:714 [inlined]
 [16] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/REPL/src/LineEdit.jl:2493
 [17] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/REPL/src/REPL.jl:1227
 [18] (::REPL.var"#49#54"{REPL.LineEditREPL, REPL.REPLBackendRef})()
    @ REPL ./task.jl:411

$ head Manifest.toml 
# This file is machine-generated - editing it directly is not advised

julia_version = "nothing"
manifest_format = "2.0"

[[deps.ATK_jll]]
deps = ["Artifacts", "Glib_jll", "JLLWrappers", "Libdl", "Pkg"]
git-tree-sha1 = "a5a8f114e4d70bee6cf82ed28b488d57f1fa9467"
uuid = "7b86fcea-f67b-53e1-809c-8f1719c154e8"
version = "2.36.0+0"

[vtjnash]

Tried deleting that line, but then failed with:

julia> using Pkg; Pkg.upgrade_manifest()
ERROR: KeyError: key "julia_version" not found
Stacktrace:
 [1] getindex
   @ ./dict.jl:481 [inlined]
 [2] Pkg.Types.Manifest(raw::Dict{String, Any}, f_or_io::String)
   @ Pkg.Types /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/manifest.jl:134
 [3] read_manifest(f_or_io::String)
   @ Pkg.Types /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/manifest.jl:198
 [4] Pkg.Types.EnvCache(env::Nothing)
   @ Pkg.Types /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/Types.jl:338
 [5] EnvCache
   @ /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/Types.jl:317 [inlined]
 [6] Pkg.Types.Context()
   @ Pkg.Types ./util.jl:471
 [7] upgrade_manifest()
   @ Pkg.API /data/vtjnash/julia/usr/share/julia/stdlib/v1.7/Pkg/src/API.jl:1673
 [8] top-level scope
   @ REPL[1]:1

[DilumAluthge]

Should be relatively easy to fix, I think we can just change a parse to a tryparse or something like that. I'll make a PR and ping Ian for review.

[StefanKarpinski]

How about just leaving that entry out when we don't have a value instead of using "nothing" as a value?

[IanButterworth]

I responded to your other message here #2610 (comment)

---

That sounds good to me. It wouldn't break the base heuristic
https://github.com/JuliaLang/julia/blob/15c19c8a6b1c1a87e6dd24fd058de5192826b250/base/loading.jl#L560-L570

But we would want to get that change out before people start generating manifests with julia_version = "nothing" in it, so could block the 1.7 beta?

[IanButterworth]

Proposed implementation #2612