MethodError Mystery: Unexpected Third Argument in Constructor Call After Julia Kernel Upgrade (1.5 to 1.9)

General Usage
1

Sorry in advance if this question is stupid and belongs in the ‘new to julia’ subforum. From what I could gather that one is focused more on installing julia, so I put it here instead.

Hey!
I am trying to get some code to run on a newer julia kernel version (jump from 1.5 to 1.9) including newer package versions so I have to debug a lot of function arguments.

I am hardstuck on a very specific one:

When calling

A = constructor(b, c)

running the code fails with the following method error:

MethodError: no method matching Constructor(::b,::c,::d).

Closest candidates are:
    Constructor(::b,::c)

When printing typeof(b) and typeof(c) before the constructor call, it is showing the correct type.

Why is there suddenly a third argument showing up in the MethodError? How can I call the constructor without this mysterious third argument?

In case this is a problem with the specific package containing the constructor in question, here is my code:

println(SimpleGraph(0))
println(typeof(SimpleGraph(0)))
println(typeof([]))
new_graph = EmbeddedGraph(SimpleGraph(0),[])

and the output:

SimpleGraph{Int64}(0, Vector{Int64}[])
SimpleGraph{Int64}
Vector{Any}

MethodError: no method matching EmbeddedGraph(::SimpleGraph{Int64}, ::Vector{Any}, ::EmbeddedGraphs.var"#6#7"{Distances.Euclidean})

Closest candidates are:
  EmbeddedGraph(::SimpleGraph{T}, ::Vector{Vector{Float64}}, ::Function) where T<:Integer
   @ EmbeddedGraphs ~/.julia/packages/EmbeddedGraphs/hxyfT/src/embeddedgraph.jl:19
  EmbeddedGraph(::SimpleGraph, ::Array)
   @ EmbeddedGraphs ~/.julia/packages/EmbeddedGraphs/hxyfT/src/embeddedgraph.jl:23
  EmbeddedGraph(::SimpleGraph, ::Array, ::Distances.Metric)
   @ EmbeddedGraphs ~/.julia/packages/EmbeddedGraphs/hxyfT/src/embeddedgraph.jl:24
  ...


Stacktrace:
 [1] EmbeddedGraph(graph::SimpleGraph{Int64}, vertexpos::Vector{Any}, distance::Distances.Euclidean)
   @ EmbeddedGraphs ~/.julia/packages/EmbeddedGraphs/hxyfT/src/embeddedgraph.jl:24
 [2] EmbeddedGraph(graph::SimpleGraph{Int64}, vertexpos::Vector{Any})
   @ EmbeddedGraphs ~/.julia/packages/EmbeddedGraphs/hxyfT/src/embeddedgraph.jl:23
 [3] regenerate_graph(vertices::Matrix{Float64}, grids_weights_col_ptr::Vector{Int64}, grids_weights_row_val::Vector{Int64})
   @ Main ./In[90]:8
 [4] load_static_test_case(id::String)
   @ Main ./In[68]:9
 [5] simulate_grid(r::Int64)
   @ Main ./In[72]:4
 [6] top-level scope
   @ In[91]:14

Where is that ::EmbeddedGraphs.var"#6#7"{Distances.Euclidean}) coming from? I am so confused!

Addon:

When running

@code_warntype EmbeddedGraph(SimpleGraph(0),[])

I get the following output:

MethodInstance for EmbeddedGraph(::SimpleGraph{Int64}, ::Vector{Any})
  from EmbeddedGraph(graph::SimpleGraph, vertexpos::Array) @ EmbeddedGraphs ~/.julia/packages/EmbeddedGraphs/hxyfT/src/embeddedgraph.jl:23
Arguments
  #self#::Type{EmbeddedGraph}
  graph::SimpleGraph{Int64}
  vertexpos::Vector{Any}
Body::Union{}
1 ─     EmbeddedGraphs.EmbeddedGraph(graph, vertexpos, EmbeddedGraphs.euclidean)
└──     Core.Const(:(return %1))
2

I’m not acquainted with EmbeddedGraphs.jl, and it seems unmaintained, but giving the coordinate vector an element type seems to help:

julia> EmbeddedGraph(SimpleGraph(0), Vector{Vector{Float64}}())
EmbeddedGraph{Int64}(SimpleGraph{Int64}(0, Vector{Int64}[]), Vector{Float64}[], EmbeddedGraphs.var"#4#5"{Vector{Vector{Float64}}, EmbeddedGraphs.var"#6#7"{Distances.Euclidean}}(Vector{Float64}[], EmbeddedGraphs.var"#6#7"{Distances.Euclidean}(Distances.Euclidean(0.0))))

NB: in case you don’t know, the T[] syntax is basically syntax sugar for Vector{T}(). When the type T is omitted, it basically defaults to Any, meaning there’s no constraint on the element type, which seems to be problematic for EmbeddedGraphs.jl.

3

tangential, but why not to 1.10?

1 Like
4

That helped! Thank you so much :slight_smile:

1 Like
5

Because I forgot to run ‘juliaup update’ :frowning: Thanks for the hint!