More problems trying to add packages from private repos

General Usage
10

@mkitti I can, yes.

@GunnarFarneback, I created the startup file as instructed here. The following then happens… Thanks for your help!

julia> ENV["JULIA_PKG_USE_CLI_GIT"]
"true"

julia> using Pkg

julia> Pkg.add(url="git@github.com:users/packagename.jl.git")
ERROR: invalid git HEAD (reference 'refs/heads/master' not found)
Stacktrace:
  [1] pkgerror(msg::String)
    @ Pkg.Types /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/Types.jl:68
  [2] check_valid_HEAD(repo::LibGit2.GitRepo)
    @ Pkg.GitTools /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/GitTools.jl:329
  [3] (::Pkg.Types.var"#42#43"{Pkg.Types.Context, Pkg.Types.PackageSpec, String})(repo::LibGit2.GitRepo)
    @ Pkg.Types /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/Types.jl:677
  [4] with(f::Pkg.Types.var"#42#43"{Pkg.Types.Context, Pkg.Types.PackageSpec, String}, obj::LibGit2.GitRepo)
    @ LibGit2 /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/LibGit2/src/types.jl:1150
  [5] handle_repo_add!(ctx::Pkg.Types.Context, pkg::Pkg.Types.PackageSpec)
    @ Pkg.Types /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/Types.jl:676
  [6] handle_repos_add!(ctx::Pkg.Types.Context, pkgs::Vector{Pkg.Types.PackageSpec})
    @ Pkg.Types /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/Types.jl:743
  [7] add(ctx::Pkg.Types.Context, pkgs::Vector{Pkg.Types.PackageSpec}; preserve::Pkg.Types.PreserveLevel, platform::Base.BinaryPlatforms.Platform, kwargs::Base.Pairs{Symbol, Base.TTY, Tuple{Symbol}, NamedTuple{(:io,), Tuple{Base.TTY}}})
    @ Pkg.API /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:248
  [8] add(pkgs::Vector{Pkg.Types.PackageSpec}; io::Base.TTY, kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Pkg.API /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:149
  [9] add(pkgs::Vector{Pkg.Types.PackageSpec})
    @ Pkg.API /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:144
 [10] #add#26
    @ /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:141 [inlined]
 [11] add
    @ /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:141 [inlined]
 [12] add(; name::Nothing, uuid::Nothing, version::Nothing, url::String, rev::Nothing, path::Nothing, mode::Pkg.Types.PackageMode, subdir::Nothing, kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Pkg.API /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:166
 [13] top-level scope
    @ REPL[2]:1

caused by: GitError(Code:EUNBORNBRANCH, Class:Reference, reference 'refs/heads/master' not found)
Stacktrace:
  [1] macro expansion
    @ /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/LibGit2/src/error.jl:110 [inlined]
  [2] head(repo::LibGit2.GitRepo)
    @ LibGit2 /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/LibGit2/src/reference.jl:44
  [3] check_valid_HEAD(repo::LibGit2.GitRepo)
    @ Pkg.GitTools /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/GitTools.jl:327
  [4] (::Pkg.Types.var"#42#43"{Pkg.Types.Context, Pkg.Types.PackageSpec, String})(repo::LibGit2.GitRepo)
    @ Pkg.Types /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/Types.jl:677
  [5] with(f::Pkg.Types.var"#42#43"{Pkg.Types.Context, Pkg.Types.PackageSpec, String}, obj::LibGit2.GitRepo)
    @ LibGit2 /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/LibGit2/src/types.jl:1150
  [6] handle_repo_add!(ctx::Pkg.Types.Context, pkg::Pkg.Types.PackageSpec)
    @ Pkg.Types /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/Types.jl:676
  [7] handle_repos_add!(ctx::Pkg.Types.Context, pkgs::Vector{Pkg.Types.PackageSpec})
    @ Pkg.Types /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/Types.jl:743
  [8] add(ctx::Pkg.Types.Context, pkgs::Vector{Pkg.Types.PackageSpec}; preserve::Pkg.Types.PreserveLevel, platform::Base.BinaryPlatforms.Platform, kwargs::Base.Pairs{Symbol, Base.TTY, Tuple{Symbol}, NamedTuple{(:io,), Tuple{Base.TTY}}})
    @ Pkg.API /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:248
  [9] add(pkgs::Vector{Pkg.Types.PackageSpec}; io::Base.TTY, kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Pkg.API /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:149
 [10] add(pkgs::Vector{Pkg.Types.PackageSpec})
    @ Pkg.API /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:144
 [11] #add#26
    @ /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:141 [inlined]
 [12] add
    @ /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:141 [inlined]
 [13] add(; name::Nothing, uuid::Nothing, version::Nothing, url::String, rev::Nothing, path::Nothing, mode::Pkg.Types.PackageMode, subdir::Nothing, kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Pkg.API /Applications/Julia-1.7.app/Contents/Resources/julia/share/julia/stdlib/v1.7/Pkg/src/API.jl:166
 [14] top-level scope
    @ REPL[2]:1