[vera-rubin]

has_negative_edge_cycle_spfa returns false when vertex 1 can't reach a negative cycle, despite its promise to detect any negative weight cycle. For example, this graph has an isolated vertex 1 and a cycle of weight -1:

using Graphs
g = SimpleDiGraph(3)
add_edge!(g, 2, 3)
add_edge!(g, 3, 2)
has_negative_edge_cycle_spfa(g, [0 0 0; 0 0 -2; 0 1 0]) # false, expected true

We initialize SPFA from every vertex using a shared internal helper, as the Bellman–Ford predicate already does.

We've added a regression test and run the existing SPFA and Bellman–Ford tests.

Tested with Graphs 1.15.0 (dffc7a6) and Julia 1.10.12.

— ChipLab

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.47%. Comparing base (dffc7a6) to head (e7bbe14).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #534   +/-   ##
=======================================
  Coverage   97.47%   97.47%           
=======================================
  Files         128      128           
  Lines        7811     7814    +3     
=======================================
+ Hits         7614     7617    +3     
  Misses        197      197           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.