[Bug]: Retrieving posteriors of partially initialized `ResizableArray` tries to access uninitialized entries

[wouterwln]

Description

GraphPPL can partially initialize arrays, but they will be requested by RxInfer at some point here:

RxInfer.jl/src/model/plugins/reactivemp_inference.jl

Line 283 in 54eae40

getvarref(model::GraphPPL.Model, container::AbstractArray) = map(element -> getvarref(model, element), container)

We will request these elements and then it will be undefined and break.

Expected Behavior

I expect it to return a posterior

Actual Behavior

It crashes

Minimal Reproducible Example or steps to reproduce the issue

using RxInfer

@model function baby_model(y)
    μ[2] ~ Normal(mean=0, var=1)
    y ~ Normal(mean=μ[2], var=1)
end

infer(model = baby_model(), data = (y = 0.0,))

Error Message / Stack Trace

UndefRefError: access to undefined reference

Stacktrace:
  [1] getindex
    @ ./essentials.jl:917 [inlined]
  [2] recursive_getindex
    @ ~/.julia/packages/GraphPPL/IVPQ2/src/resizable_array.jl:144 [inlined]
  [3] getindex
    @ ~/.julia/packages/GraphPPL/IVPQ2/src/resizable_array.jl:136 [inlined]
  [4] iterate
    @ ~/.julia/packages/GraphPPL/IVPQ2/src/resizable_array.jl:180 [inlined]
  [5] iterate
    @ ./generator.jl:45 [inlined]
  [6] _collect(c::GraphPPL.ResizableArray{GraphPPL.NodeLabel, Vector{GraphPPL.NodeLabel}, 1}, itr::Base.Generator{GraphPPL.ResizableArray{GraphPPL.NodeLabel, Vector{GraphPPL.NodeLabel}, 1}, RxInfer.var"#91#92"{GraphPPL.Model{MetaGraphsNext.MetaGraph{Int64, Graphs.SimpleGraphs.SimpleGraph{Int64}, GraphPPL.NodeLabel, GraphPPL.NodeData, GraphPPL.EdgeLabel, GraphPPL.Context, MetaGraphsNext.var"#4#8", Float64}, GraphPPL.PluginsCollection{Tuple{GraphPPL.VariationalConstraintsPlugin{GraphPPL.NoConstraints}, GraphPPL.MetaPlugin{GraphPPL.MetaSpecification}, RxInfer.InitializationPlugin{RxInfer.NoInit}, RxInfer.ReactiveMPInferencePlugin{RxInfer.ReactiveMPInferenceOptions{Nothing, Nothing, Nothing}}}}, RxInfer.ReactiveMPGraphPPLBackend{Static.False}, String}}}, ::Base.EltypeUnknown, isz::Base.HasShape{1})
    @ Base ./array.jl:811
  [7] collect_similar
    @ ./array.jl:720 [inlined]
  [8] map
    @ ./abstractarray.jl:3371 [inlined]
  [9] getvarref
    @ ~/.julia/dev/RxInfer/src/model/plugins/reactivemp_inference.jl:283 [inlined]
 [10] (::RxInfer.var"#89#90"{GraphPPL.Model{MetaGraphsNext.MetaGraph{Int64, Graphs.SimpleGraphs.SimpleGraph{Int64}, GraphPPL.NodeLabel, GraphPPL.NodeData, GraphPPL.EdgeLabel, GraphPPL.Context, MetaGraphsNext.var"#4#8", Float64}, GraphPPL.PluginsCollection{Tuple{GraphPPL.VariationalConstraintsPlugin{GraphPPL.NoConstraints}, GraphPPL.MetaPlugin{GraphPPL.MetaSpecification}, RxInfer.InitializationPlugin{RxInfer.NoInit}, RxInfer.ReactiveMPInferencePlugin{RxInfer.ReactiveMPInferenceOptions{Nothing, Nothing, Nothing}}}}, RxInfer.ReactiveMPGraphPPLBackend{Static.False}, String}})(v::GraphPPL.ResizableArray{GraphPPL.NodeLabel, Vector{GraphPPL.NodeLabel}, 1})
    @ RxInfer ~/.julia/dev/RxInfer/src/model/plugins/reactivemp_inference.jl:279
 [11] map!(f::RxInfer.var"#89#90"{GraphPPL.Model{MetaGraphsNext.MetaGraph{Int64, Graphs.SimpleGraphs.SimpleGraph{Int64}, GraphPPL.NodeLabel, GraphPPL.NodeData, GraphPPL.EdgeLabel, GraphPPL.Context, MetaGraphsNext.var"#4#8", Float64}, GraphPPL.PluginsCollection{Tuple{GraphPPL.VariationalConstraintsPlugin{GraphPPL.NoConstraints}, GraphPPL.MetaPlugin{GraphPPL.MetaSpecification}, RxInfer.InitializationPlugin{RxInfer.NoInit}, RxInfer.ReactiveMPInferencePlugin{RxInfer.ReactiveMPInferenceOptions{Nothing, Nothing, Nothing}}}}, RxInfer.ReactiveMPGraphPPLBackend{Static.False}, String}}, out::Dictionaries.UnorderedDictionary{Symbol, Any}, d::Dictionaries.UnorderedDictionary{Symbol, Any})
    @ Dictionaries ~/.julia/packages/Dictionaries/L8pH7/src/map.jl:66
 [12] map(f::Function, d::Dictionaries.UnorderedDictionary{Symbol, Any})
    @ Dictionaries ~/.julia/packages/Dictionaries/L8pH7/src/map.jl:106
 [13] map(f::Function, vardict::GraphPPL.VarDict{Any})
    @ GraphPPL ~/.julia/packages/GraphPPL/IVPQ2/src/graph_engine.jl:615
 [14] getvardict
    @ ~/.julia/dev/RxInfer/src/model/plugins/reactivemp_inference.jl:279 [inlined]
 [15] getvardict
    @ ~/.julia/dev/RxInfer/src/model/model.jl:40 [inlined]
 [16] batch_inference(; model::GraphPPL.ModelGenerator{typeof(baby_model), @Kwargs{}, GraphPPL.PluginsCollection{Tuple{}}, RxInfer.ReactiveMPGraphPPLBackend{Static.False}, String}, data::@NamedTuple{y::Float64}, initialization::Nothing, constraints::Nothing, meta::Nothing, options::Nothing, returnvars::Nothing, predictvars::Nothing, iterations::Nothing, free_energy::Bool, free_energy_diagnostics::Tuple{RxInfer.ObjectiveDiagnosticCheckNaNs, RxInfer.ObjectiveDiagnosticCheckInfs}, allow_node_contraction::Bool, showprogress::Bool, callbacks::Nothing, addons::Nothing, postprocess::DefaultPostprocess, warn::Bool, catch_exception::Bool)
    @ RxInfer ~/.julia/dev/RxInfer/src/inference/batch.jl:209
 [17] batch_inference
    @ ~/.julia/dev/RxInfer/src/inference/batch.jl:96 [inlined]
 [18] #312
    @ ~/.julia/dev/RxInfer/src/inference/inference.jl:545 [inlined]
 [19] with_session(f::RxInfer.var"#312#314"{GraphPPL.ModelGenerator{typeof(baby_model), @Kwargs{}, GraphPPL.PluginsCollection{Tuple{}}, RxInfer.ReactiveMPGraphPPLBackend{Static.False}, String}, @NamedTuple{y::Float64}, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Nothing, Bool, Tuple{RxInfer.ObjectiveDiagnosticCheckNaNs, RxInfer.ObjectiveDiagnosticCheckInfs}, Bool, Bool, Bool, Nothing, Nothing, DefaultPostprocess, Nothing, Bool, Bool, Bool}, session::RxInfer.Session, label::Symbol)
    @ RxInfer ~/.julia/dev/RxInfer/src/session.jl:253
 [20] #infer#311
    @ ~/.julia/dev/RxInfer/src/inference/inference.jl:515 [inlined]
 [21] top-level scope
    @ ~/.julia/dev/RxInfer/jl_notebook_cell_df34fa98e69747e1a8f8a730347b8e2f_W0sZmlsZQ==.jl:8

Julia Version

1.11

RxInfer Version

Latest stable

Environment Information

Session ID (Optional)

No response

Additional Context

No response