MWE
julia> using MetaGraphsNext # v0.6.0
julia> struct Foo end
julia> g2 = MetaGraph(DiGraph(), label_type=Int, vertex_data_type=Foo)
Meta graph based on a SimpleDiGraph{Int64} with vertex labels of type Int64, vertex metadata of type Foo, edge metadata of type Nothing, graph metadata given by nothing, and default weight 1.0
julia> savegraph("data.dot", g2, DOTFormat())
ERROR: MethodError: no method matching length(::Foo)
Closest candidates are:
length(::LibGit2.GitStatus)
@ LibGit2 ~/.julia/juliaup/julia-1.10.0-rc1+0.x64.linux.gnu/share/julia/stdlib/v1.10/LibGit2/src/status.jl:21
length(::Tables.DictRowTable)
@ Tables ~/.julia/packages/Tables/NSGZI/src/dicts.jl:118
length(::Base.MethodSpecializations)
@ Base reflection.jl:1164
...
Stacktrace:
[1] show_meta_list(io::IOStream, meta::Foo)
@ MetaGraphsNext ~/.julia/packages/MetaGraphsNext/YvA1m/src/persistence.jl:31
[2] savedot(io::IOStream, meta_graph::MetaGraph{…})
@ MetaGraphsNext ~/.julia/packages/MetaGraphsNext/YvA1m/src/persistence.jl:76
[3] #32
@ ~/.julia/packages/MetaGraphsNext/YvA1m/src/persistence.jl:100 [inlined]
[4] open(::MetaGraphsNext.var"#32#33"{MetaGraph{…}}, ::String, ::Vararg{String}; kwargs::@Kwargs{})
@ Base ./io.jl:396
[5] open
@ Base ./io.jl:393 [inlined]
[6] savegraph(file::String, meta_graph::MetaGraph{…}, ::DOTFormat)
@ MetaGraphsNext ~/.julia/packages/MetaGraphsNext/YvA1m/src/persistence.jl:99
[7] top-level scope
@ REPL[13]:1
Some type information was truncated. Use `show(err)` to see complete types.
MWE