type ReadOnlyMemoryError has no field code

[giordano]

Julia v1.6.0, my registry is a git repository, I checked out a branch different from master, trying to run up I get

(tmp) pkg> up
    Updating registry at `~/.julia/registries/General`
    Updating git-repo `https://github.com/JuliaRegistries/General.git`
┌ Warning: Cannot perform fast-forward merge
└ @ LibGit2 /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/LibGit2/src/merge.jl:237
ERROR: type ReadOnlyMemoryError has no field code
Stacktrace:
  [1] getproperty(x::ReadOnlyMemoryError, f::Symbol)
    @ Base ./Base.jl:33
  [2] commit(rb::LibGit2.GitRebase, sig::LibGit2.GitSignature)
    @ LibGit2 /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/LibGit2/src/rebase.jl:86
  [3] (::LibGit2.var"#148#149"{LibGit2.GitRepo, String, String})(head_ref::LibGit2.GitReference)
    @ LibGit2 /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/LibGit2/src/LibGit2.jl:836
  [4] with(f::LibGit2.var"#148#149"{LibGit2.GitRepo, String, String}, obj::LibGit2.GitReference)
    @ LibGit2 /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/LibGit2/src/types.jl:1150
  [5] rebase! (repeats 2 times)
    @ /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/LibGit2/src/LibGit2.jl:813 [inlined]
  [6] update_registries(ctx::Pkg.Types.Context, regs::Vector{Pkg.Types.RegistrySpec}; force::Bool)
    @ Pkg.Types /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/Types.jl:1204
  [7] up(ctx::Pkg.Types.Context, pkgs::Vector{Pkg.Types.PackageSpec}; level::Pkg.Types.UpgradeLevel, mode::Pkg.Types.PackageMode, update_registry::Bool, kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Pkg.API /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/API.jl:236
  [8] up
    @ /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/API.jl:230 [inlined]
  [9] #up#38
    @ /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/API.jl:73 [inlined]
 [10] up(pkgs::Vector{Pkg.Types.PackageSpec})
    @ Pkg.API /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/API.jl:72
 [11] do_cmd!(command::Pkg.REPLMode.Command, repl::REPL.LineEditREPL)
    @ Pkg.REPLMode /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/REPLMode/REPLMode.jl:408
 [12] do_cmd(repl::REPL.LineEditREPL, input::String; do_rethrow::Bool)
    @ Pkg.REPLMode /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/REPLMode/REPLMode.jl:386
 [13] do_cmd
    @ /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/REPLMode/REPLMode.jl:377 [inlined]
 [14] (::Pkg.REPLMode.var"#24#27"{REPL.LineEditREPL, REPL.LineEdit.Prompt})(s::REPL.LineEdit.MIState, buf::IOBuffer, ok::Bool)
    @ Pkg.REPLMode /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/Pkg/src/REPLMode/REPLMode.jl:550
 [15] #invokelatest#2
    @ ./essentials.jl:708 [inlined]
 [16] invokelatest
    @ ./essentials.jl:706 [inlined]
 [17] run_interface(terminal::REPL.Terminals.TextTerminal, m::REPL.LineEdit.ModalInterface, s::REPL.LineEdit.MIState)
    @ REPL.LineEdit /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/LineEdit.jl:2441
 [18] run_frontend(repl::REPL.LineEditREPL, backend::REPL.REPLBackendRef)
    @ REPL /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/REPL/src/REPL.jl:1126
 [19] (::REPL.var"#44#49"{REPL.LineEditREPL, REPL.REPLBackendRef})()
    @ REPL ./task.jl:406

[giordano]

In particular, the local branch was rebased on top of master and was different from the one from origin, I believe the divergence between the local and the remote branch is what triggers the issue (but why should Pkg care about it?)

[vtjnash]

Why didn't we print the whole caused-by stacktrace here, and instead truncate it after the first exception?