Cannot recreate JumpProcess example in Catalyst

General Usage
1

I’ve been using Catalyst successfully for the past few weeks. It’s pretty great! However, I recently tried to update PlutoUI from 0.7.14 to 0.7.51 (not sure why such an old version was installed). I then updated all my packages which I believe installed a new version of ModelingToolkit (9.65.0 to 9.68.0). This seems to have broken the creation of any JumpProblem with a discrete event. This example, which I’ve recreated successfully several times before, throws the following error:

ERROR: type Nothing has no field head
Stacktrace:
  [1] getproperty(x::Nothing, f::Symbol)
    @ Base ./Base.jl:37
  [2] _reset_aggregator!(expr::Nothing, integrator::Symbol)
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/jumps/jumpsystem.jl:14
  [3] _reset_aggregator!(expr::Expr, integrator::Symbol) (repeats 8 times)
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/jumps/jumpsystem.jl:21
  [4] _reset_aggregator!(expr::Expr, integrator::Symbol)
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/jumps/jumpsystem.jl:15
  [5] compile_affect(eqs::Vector{…}, cb::ModelingToolkit.SymbolicDiscreteCallback, sys::JumpSystem{…}, dvs::Vector{…}, ps::Vector{…}; outputidxs::Nothing, expression::Type, checkvars::Bool, eval_expression::Bool, eval_module::Module, postprocess_affect_expr!::typeof(ModelingToolkit._reset_aggregator!), kwargs::@Kwargs{})
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/callbacks.jl:705
  [6] generate_timed_callback(cb::ModelingToolkit.SymbolicDiscreteCallback, sys::JumpSystem{…}, dvs::Vector{…}, ps::Vector{…}; postprocess_affect_expr!::Function, kwargs::@Kwargs{…})
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/callbacks.jl:1031
  [7] generate_discrete_callback(cb::ModelingToolkit.SymbolicDiscreteCallback, sys::JumpSystem{…}, dvs::Vector{…}, ps::Vector{…}; postprocess_affect_expr!::Function, kwargs::@Kwargs{…})
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/callbacks.jl:0
  [8] generate_discrete_callback
    @ ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/callbacks.jl:1071 [inlined]
  [9] #690
    @ ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/callbacks.jl:1116 [inlined]
 [10] iterate
    @ ./generator.jl:47 [inlined]
 [11] _collect(c::Vector{…}, itr::Base.Generator{…}, ::Base.EltypeUnknown, isz::Base.HasShape{…})
    @ Base ./array.jl:854
 [12] collect_similar(cont::Vector{ModelingToolkit.SymbolicDiscreteCallback}, itr::Base.Generator{Vector{…}, ModelingToolkit.var"#690#691"{…}})
    @ Base ./array.jl:763
 [13] map(f::Function, A::Vector{ModelingToolkit.SymbolicDiscreteCallback})
    @ Base ./abstractarray.jl:3285
 [14] generate_discrete_callbacks(sys::JumpSystem{…}, dvs::Vector{…}, ps::Vector{…}; kwargs::@Kwargs{…})
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/callbacks.jl:1115
 [15] process_events(sys::JumpSystem{…}; callback::Nothing, kwargs::@Kwargs{…})
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/callbacks.jl:1134
 [16] process_events
    @ ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/callbacks.jl:1127 [inlined]
 [17] JumpProblem(js::JumpSystem{…}, prob::DiscreteProblem{…}, aggregator::JumpProcesses.NullAggregator; callback::Nothing, eval_expression::Bool, eval_module::Module, kwargs::@Kwargs{})
    @ ModelingToolkit ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/jumps/jumpsystem.jl:582
 [18] JumpProblem
    @ ~/.julia/packages/ModelingToolkit/ZOG3I/src/systems/jumps/jumpsystem.jl:539 [inlined]
 [19] #JumpProblem#185
    @ ~/.julia/packages/Catalyst/48wH3/src/reactionsystem_conversions.jl:872 [inlined]
 [20] JumpProblem
    @ ~/.julia/packages/Catalyst/48wH3/src/reactionsystem_conversions.jl:869 [inlined]
 [21] JumpProblem(jinputs::JumpInputs{JumpSystem{…}, DiscreteProblem{…}})
    @ Catalyst ~/.julia/packages/Catalyst/48wH3/src/reactionsystem_conversions.jl:869
 [22] top-level scope
    @ REPL[21]:1
Some type information was truncated. Use `show(err)` to see complete types.

I tried downgrading ModelingToolkit back to 9.65.0 and uninstalled PlutoUI (can’t imagine that’s the problem but did it anyway) but it still does not fix the issue. I can’t figure out how I broke this!

Running Julia 1.10.5. Current package versions:

  [824d6782] Bonito v4.0.3
  [479239e8] Catalyst v14.4.1
  [31a5f54b] Debugger v0.7.10
  [0c46a032] DifferentialEquations v7.16.0
  [96684042] InformationMeasures v0.3.1
  [ccbc3e58] JumpProcesses v9.14.2
  [23fbe1c1] Latexify v0.16.6
⌃ [961ee093] ModelingToolkit v9.65.0
  [1dea7af3] OrdinaryDiffEq v6.92.0
  [c3e4b0f8] Pluto v0.20.5
  [295af30f] Revise v3.7.2
  [2913bbd2] StatsBase v0.34.4
  [789caeaf] StochasticDiffEq v6.74.1
  [276b4fcb] WGLMakie v0.11.2

I tried a fresh install of Catalyst in a new environment and still run into this issue.