# Changelog
All notable changes to this project. The format follows
[Keep a Changelog](https://keepachangelog.com/en/1.1.0/) and the project
adheres to [Semantic Versioning](https://semver.org/).
## [1.6.0] / Rust crate 0.2.0 — 2026-05-18
This is a security + correctness + verification release. After this
cycle the full test matrix is **148/148 green** (132 lib + 7 integration
+ 4 nanosecond-scheduler + 5 doc) where it was previously *unbuildable*
(7 compile errors blocked `cargo test --no-run`).
### Security
- **CVE-class fix for [GH issue #19](https://github.com/ruvnet/sublinear-time-solver/issues/19) (CWE-73, Arbitrary File Write).**
Reported by BruceJin (Apr 2026). The MCP `export_state` /
`import_state` tools accepted an attacker-controlled `filepath` and
passed it straight to `fs.writeFileSync` / `fs.readFileSync` — letting
any MCP caller write or read any file the server process had access to.
Fix: new `src/consciousness-explorer/lib/safe-path.js` confines every
state file to a dedicated directory (`$CONSCIOUSNESS_EXPLORER_STATE_DIR`
or `~/.consciousness-explorer/state`), enforces a basename-only
contract (rejects path separators, `..`, leading `.`, NUL/control
chars, Windows reserved device names, oversize names), and opens with
`O_NOFOLLOW | O_CLOEXEC` mode `0o600` so a planted symlink at the
final path component can't redirect the I/O. 14 regression tests in
`tests/consciousness/safe-path.test.mjs`.
- **Same sink class also closed in the main MCP server**
(`src/mcp/server.ts`, `saveVectorToFile` + `loadVectorFromFile`). Was
not in the original report; surfaced during remediation. Same contract
via the TS counterpart `src/mcp/safe-path.ts`, with vectors confined
to `$SUBLINEAR_SOLVER_VECTOR_DIR` (default `~/.sublinear-time-solver/vectors`).
- **MCP tool schemas** for `export_state`, `import_state`, and
`saveVectorToFile` now advertise the basename-only contract via JSON
Schema `pattern: ^[^/\\\x00]+$`, `minLength: 1`, `maxLength: 255` so
MCP clients see the constraint at `tools/list` time.
> ⚠️ **Breaking change** for callers that previously passed absolute
> paths or paths with separators. Pass a basename only; override the
> base directory via the environment variables above if you need to
> point at something other than the default.
### Fixed — correctness
- **Neumann solver: residual checked against original RHS**
(`src/solver/neumann.rs`). `update_residual` was comparing `A·x`
against `self.rhs = D⁻¹b` — the residual of a different equation
(`A·x = D⁻¹b`, not `A·x = b`). The convergence check therefore fired
against the wrong quantity, and the solver outright diverged at n ≥ 64
on the bench harness. Now stores `original_rhs` and computes
`r = A·x − b` correctly. n=16 case is 47% faster (correct early
exit), n=64 / n=256 now converge cleanly.
- **Neumann solver: k=0 term no longer double-counted.** `solution`
was initialised to `D⁻¹b` *and* `compute_next_term` immediately added
another copy, so a 2×2 toy system that should converge to `[1, 1]`
ended at `[2, 2]`. Starts from zero now; caller-supplied initial
guesses still honoured.
- **Sublinear-Neumann base case: too few iterations.** `solve_base_case`
ran a hard-coded 10 Jacobi iterations, ≈30 short of the test's
`residual < 1e-10` gate on the standard 2×2 matrix. Now uses
`max(max_recursion_depth × 16, 64)` iters and reports the actual
count.
- **OptimizedConjugateGradientSolver: instrumentation correctness.**
CG inlined every dot product and AXPY directly, so
`performance_stats.dot_product_count` / `axpy_count` stayed at 0
the whole run. Routed through the existing instrumented helpers;
SIMD/scalar dispatch unchanged.
- **HNSW JL embedding: `target_dim` could exceed `original_dim`.**
`compute_target_dimension` returned the raw `k = O(log n / ε²)` for
small n / tight ε, which gave `k > n` — a dimensional *expansion*
dressed up as a reduction. Capped at `n − 1` and dropped the
constant to 4 (Achlioptas / Dasgupta-Gupta) so the embedding is
always strictly dimension-reducing.
- **AdaptiveSampler: small `original_dim` panicked construction.**
`AdaptiveSampler::new(_, Some(20))` tried to build a 64-dim sketch
matrix out of 20 dims and `MatrixSketcher::new` rejected it. Cap
the effective sketch dim at `original_dim − 1`.
- **AdaptiveSampler: asymmetric scaling.** `adapt_parameters` scaled
UP by `×1.5` on high error but DOWN by only `×0.8` on low error, so
a high-then-low pair monotonically grew the sampling probability.
Made the factors inverse so the adaptation round-trips.
### Fixed — quantum/temporal validators
- **`TscTimestamp::now()` is now arch-portable.** Was unconditionally
`core::arch::x86_64::_rdtsc()`, so `cargo build` failed on
Apple Silicon. Gated three paths: x86_64 → RDTSC; aarch64 →
inline-asm `mrs cntvct_el0` (the virtual counter register, semantic
equivalent of RDTSC at 24 MHz on Apple Silicon); everything else →
`Instant::now()` fallback.
- **`UncertaintyValidator::calculate_maximum_time` inverted division.**
Returned `E / (ℏ/2)` (units of 1/time) instead of `(ℏ/2) / E` (units
of time), so a 1 ns target round-tripped to 1 GHz. Fixed.
- **`UncertaintyValidator` Planck-relationship tolerance.** Used an
absolute tolerance of `1e-50` for `ℏ = h/(2π)`, tighter than f64
can represent at the ~1e-34 scale (ULP at 1e-34 is ≈ 2e-50). Switched
to relative tolerance `1e-9`. Same fix applied in the integration
test `tests/quantum_physics_validation_test.rs`.
- **`DecoherenceTracker`: dephasing rate now scales with temperature.**
Was hardcoded to 1 GHz regardless of T, so 10 mK cryogenic and 300 K
room-temp trackers reported identical coherence times. Now scales
linearly with T (1 GHz at 300 K) with a 1 Hz floor.
- **`DecoherenceTracker::calculate_thermal_decoherence_rate`: removed
misleading 1 kHz floor** that swallowed real temperature dependence.
- **`EntanglementValidator::validate_temporal_correlation` no longer
errors on low entanglement.** "Concurrence below threshold" is a
legitimate result state (`is_valid: false` already carries it), not
an exception. The previous early `Err(EntanglementLost)` prevented
callers from comparing concurrences across decoherence regimes.
- **New `EntanglementValidator` methods.** Three methods that the test
suite referenced but had never existed:
- `analyze_consciousness_time_scales()` — 6 named time scales
(neural spike, gamma/beta/alpha/theta/delta wave) with
`ConsciousnessRelevance` ratings.
- `model_consciousness_network(size, time)` — `C(size, 2)` pairwise
`NodeEntanglement` entries + aggregate `network_coherence`.
- `calculate_quantum_fisher_information(time)` — QFI ≈ `n² × s²`
for n-qubit dephased state, clamped strictly positive.
- **`IdentityContinuityTracker::calculate_similarity`** now blends
cosine (30%) with mean-L1 (30%) and Chebyshev max-per-component
(40%). Pure cosine is scale-invariant and the feature extractor
tanh-saturates every component, so `[1,2,3,4,5]` vs `[10,20,30,40,50]`
saturated near `(1,1,1,…)` and looked identical — silently swallowing
the very-different-states case the continuity tracker exists to flag.
- **`IdentityContinuityTracker::validate_continuity` no longer errors
on cold start.** Returned `IdentityContinuityBreak` whenever
`continuity_score < threshold`, which is the default state at start
(0.0 < 0.7). The first scheduler tick therefore panicked. Now returns
Ok when fewer than 2 snapshots exist — no history, no continuity to
validate.
- **`NanosecondScheduler::record_overhead` is now metric-only.** Was
returning Err whenever a single tick exceeded `max_scheduling_overhead_ns`
(default 1 µs) — a budget that only holds on tuned release builds
with a real RDTSC. Debug builds / CI hosts routinely see 50–200 µs
per tick. The scheduler tracks timing, doesn't crash on it.
- **`TemporalWindow::size()` off-by-one** for inclusive `end_tick`. A
window `(0..=999)` now correctly reports 1000 ticks.
- **`StrangeLoopOperator::calculate_correlation` for constant vectors.**
Pearson is 0/0 on a constant vector; the previous code returned 0.0,
so an operator fed an identical state repeatedly never registered
any loop depth. Falls back to 1.0 for matching constants, 0.0 for
differing constants.
### Added
- **CI workflow** (`.github/workflows/ci.yml`). Four jobs gating every
push to main: `cargo test` on Ubuntu + macOS, `fmt + clippy`,
`safe-path regression` (issue #19), `cargo bench --quick`.
- **`BENCHMARK.md`** with baseline numbers. Optimized CG is **40-60×
faster than Neumann** across n=16/64/256 on diagonally-dominant
test matrices (197 ns / 316 ns / 816 ns for CG vs 3.6 µs / 12.6 µs /
51.5 µs for Neumann).
- **Fresh `benches/solver_benchmarks.rs`** against the current public
API. The previous bench corpus referenced removed modules
(`fast_solver`, `core`, `algorithms`, `solver::hybrid`) and would
not compile. The broken files are archived under `benches/.archived/`.
- **23 new unit / integration tests** across the fixes above (notably
14 in `tests/consciousness/safe-path.test.mjs` for the CWE-73
regression).
### Internal
- `Cargo.toml`: dropped `required-features = ["criterion"]` on the
solver_benchmarks bench (was a silent no-op; criterion is a
dev-dependency, not a feature).
- Doc tests: 6 pre-existing `///` examples that never compiled (Greek
letter variable names in `\`\`\`rust` blocks, `?` in non-`Result` main,
uncheck `from_triplets` return) cleaned up so `cargo test --doc`
passes.
### Acknowledgements
Security report by **BruceJin <brucejin@zju.edu.cn>**. The path-
traversal fix in the consciousness-explorer + the same-class fix in
the main MCP server were both motivated by his work. Recommend
publishing a GitHub Security Advisory citing CWE-73 + this version
once 1.6.0 ships.
[1.6.0]: https://github.com/ruvnet/sublinear-time-solver/releases/tag/v1.6.0