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Record two Stryker findings from the surface nets mutation pass

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Three TryGetOtherEndpoint boundary-guard mutants (per-axis "if (x + 1 >=
sizeX) return false;" forced to "if (true) return false;") were reported
Survived despite being exercised by the X/Y/Z open-boundary tests. Hand-
mutating all three and running dotnet test directly failed 11 of 24
SurfaceNetsTests, confirming a vstest-runner coverage-attribution false
survivor (same class of caveat already recorded for CultMath's mtp runner,
here under the default runner). Recorded under Known tool caveat.

Separately, adding stryker-config.json in the same cut that first uses it
defeats --since line scoping: Stryker fell back to mutating the whole
GameCult.Geometry.csproj glob ("Non-CSharp files in test project were
changed"), not just the new files, which is why the run's survivor list
includes CultGeometryIsoSurface.cs, CultGeometryDocuments.cs, and
CultGeometryPrimitives.cs. Recorded under Follow-ups so a later diff-only
cut isn't surprised by the difference.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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Meta Vens 2026-09-25 18:44:36 +02:00
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@ -75,6 +75,18 @@ inside a `static readonly` field initializer as unproven until confirmed
with a direct `dotnet test` run against the same mutation; do not triage it
as a missing test without that check.
The default `vstest` runner has its own analog. GameCult.Geometry.Tests's
first `--since` pass reported three `Boolean mutation -> true` survivors in
`CultGeometrySurfaceNets.TryGetOtherEndpoint` (the per-axis `if (x + 1 >=
sizeX) return false;` guards, mutated to `if (true) return false;`), despite
X/Y/Z-axis open-boundary tests that exercise exactly those guards. Hand-
mutating all three and running `dotnet test tests/GameCult.Geometry.Tests
--filter FullyQualifiedName~SurfaceNetsTests` directly failed 11 of 24 tests,
confirming the mutants are well-covered and Stryker's coverage-based test
selection mis-attributed (or dropped) their covering tests. Treat a survivor
that looks like it must be covered as unproven until confirmed the same way,
regardless of which runner is in play.
## Follow-ups
CultMath.Tests and GameCult.Geometry.Tests are the only projects currently
@ -90,6 +102,16 @@ added surface nets; a full-project baseline (running mutation against all of
`CultGeometryPrimitives`, not just the diff) is a recorded follow-up, not
something either cut did.
That first `--since` pass did not actually stay diff-scoped: adding
`stryker-config.json` itself in the same cut that first used it made Stryker
log "391 mutants will be tested because: Non-CSharp files in test project
were changed" and mutate the whole `mutate` glob (all four existing
GameCult.Geometry source files), not just the new surface-nets files. A cut
that changes a non-C# file inside the test project (a fixture, this config
file, anything under `Fixtures/`) loses `--since` line-level scoping for that
run; a future cut whose diff is C#-only, against a base commit that already
has `stryker-config.json`, should scope correctly.
`GameCult.Caching`, `GameCult.Mesh` (+ `.Quic`, `.Quic.Native`),
`GameCult.Networking` (+ `.WebSockets`), and the non-.NET runtimes
(`cultcache-rs/py/ts`, `cultmesh-*`, `cultnet-*`) each still need their own