Skip to content

fix: avoid mutating buffer being iterated when updating total_sub incidence #114

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
AayushSabharwal merged 2 commits into from
Jun 18, 2026
Merged

fix: avoid mutating buffer being iterated when updating total_sub incidence #114

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
1f6b037
fix: avoid mutating buffer being iterated when updating `total_sub` i…
AayushSabharwal Jun 18, 2026
c807c2f
docs: add comment explaining graph validity in `generate_system_equat…
AayushSabharwal Jun 18, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 8 additions & 1 deletion lib/ModelingToolkitTearing/src/reassemble.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -425,6 +425,10 @@ function generate_system_equations!(state::TearingState, neweqs::Vector{Equation
(var_to_diff[i] !== nothing && !isempty(𝑑neighbors(graph, var_to_diff[i]))))
end

# NOTE: `state.structure.graph` should be accurate despite `generate_system_equations!`
# mutating the graph (when generating differential equations/populating `total_sub`).
# If the graph disagrees with symbolic incidence at any point during the execution of
# this function, then there is some invalid operation happening on the graph.
digraph = DiCMOBiGraph{false}(graph, var_eq_matching)
for (i, scc) in enumerate(var_sccs)
# note that the `vscc <-> escc` relation is a set-to-set mapping, and not
Expand Down Expand Up @@ -967,7 +971,10 @@ function codegen_equation!(eg::EquationGenerator,
# We will add `neweq.lhs` to `total_sub`, so any equation involving it won't be
# incident on it. Remove the edges incident on `iv` from the graph, and add
# the replacement vertices from `ieq` so that the incidence is still correct.
for e in 𝑑neighbors(graph, iv)
#
# The `copy` is necessary because `rem_edge!` will mutate the buffer that we
# iterate over.
for e in copy(𝑑neighbors(graph, iv))
e == ieq && continue
for v in 𝑠neighbors(graph, ieq)
add_edge!(graph, e, v)
Expand Down
Loading