# cargo-mutants configuration for heuropt.
#
# Run with:
#   cargo install cargo-mutants
#   cargo mutants                          # full sweep (slow)
#   cargo mutants --in-diff HEAD~1         # only mutate recently-changed lines
#
# IMPORTANT: pass `--all-features` (or at least `--features async,serde`).
# Without them the async `run_async` paths and the `explorer` module are
# not compiled, so their mutants come back as unviable/missed noise rather
# than being exercised by the test suite.
#
# Note: `--test-tool nextest` does not accept the libtest-style
# `--test-threads=1` set below; for a nextest run pass `--no-config` (and
# re-add `--all-features` / the `--file` filters you need on the CLI).
#
# A *surviving* mutation = the test suite passed despite a code change,
# which usually means a missing test or a missing invariant.
#
# This isn't gated CI; it's an advisory tool. The property tests in
# tests/properties.rs and the per-algorithm exact-output snapshot tests
# in tests/algorithm_properties.rs are the natural places to land new
# invariants discovered via mutation runs.
#
# Mutation-coverage notes (2026-05 campaign — catch rate ~74% -> ~85%):
#   - tests/algorithm_properties.rs pins an exact final-population
#     snapshot for every algorithm at a fixed seed. Those snapshots use
#     deliberately *hard* fixtures (3-D Rosenbrock, an 8-city scattered
#     TSP, a budget-sensitive multi-fidelity problem): on convex /
#     trivially-solved problems the optimizers converge to the same
#     answer regardless of arithmetic mutations, which hides them.
#   - The residual MISSED mutants are dominated by (a) equivalent
#     mutants — e.g. `<` vs `<=` at a boundary the inputs never hit —
#     and (b) arithmetic the optimizers are mathematically robust to.
#   - TIMEOUT mutants here are loop-bound mutations that make an
#     offspring-collection loop non-terminating; cargo-mutants reports
#     those *as detected*, in their own category separate from MISSED.
#
# Performance notes (2026-05 profiling campaign — compare_profile
# whole-program callgrind Ir 357.06B -> 165.31B, -53.7%):
#   - `benches/compare_profile.rs` profiles the whole `compare` example
#     workload under callgrind via gungraun; it drove the seven perf
#     commits of this campaign. (It's in `exclude_globs` below — a
#     bench harness, not behavior to mutate.)
#   - Every perf commit was bit-identical: all the tests/algorithm_-
#     properties.rs snapshots stayed green. But the round-4
#     `pareto::front::pareto_front` change adds a `dominated` bitset
#     that is *pure* skip-bookkeeping — the `dominated[j] = true` write
#     and the `if dominated[i]` early `continue` are optimization-only.
#     Deleting either leaves the returned front bit-identical (just
#     slower), so a mutation run will (correctly) report those as
#     MISSED. They are genuine equivalent mutants, not test gaps —
#     don't try to pin them with new tests.

# Files to skip mutating. We skip:
#   - examples (illustrative, not core algorithm correctness)
#   - benches (microbench harness, not behavior)
#   - the docs/* spec markdown
#   - tests_support (test helpers; mutating them changes test inputs,
#     not behavior under test)
exclude_globs = [
    "examples/**/*.rs",
    "benches/**/*.rs",
    "src/tests_support/**/*.rs",
]

# `cargo-mutants` defaults to `cargo test` for the suite. Keep that.
# `--no-shuffle` makes failure attribution deterministic.
additional_cargo_test_args = ["--", "--test-threads=1"]

# Time-out per mutated build+test cycle. Big enough for a slow test
# (proptest can take ~10s) but short enough to detect infinite loops.
timeout_multiplier = 5.0