ROADMAP.md

NexusLang Roadmap

Current Phase

• Foundation hardening and regression expansion across parser, type system, and backends.

Active Track: Range Expression Prototype Hardening

Objective

Stabilize range expression parsing and lowering behavior before introducing additional syntax forms.

Scope (Current Cycle)

• Canonical expression form: range(start, stop[, step])
• Tuple shorthand lowering: (start, stop[, step]) to range(...)
• Range loop form: for i from start to stop [by step]
• Strict loop-step rule: by requires an explicit step expression

Decision (Accepted 2026-05-11)

• Punctuation range operators .. and ..= are deferred for this cycle.
• Function and tuple forms remain the stabilized prototype surface.
• Decision reference: docs/_internal/planning/range-expression-surface-rfc-2026-05.md

Verification Matrix

• Parser hardening matrix: tests/unit/compiler/test_range_expression_hardening_matrix.py
• Backend lowering matrix (C/LLVM invariants): tests/unit/compiler/test_range_codegen_hardening_matrix.py

Exit Criteria

1. Both range hardening suites remain green in CI.
2. No regressions in nearby compiler hardening suites.
3. Broad compiler sweep remains green after range-track changes.

Next Candidate Track

• Revisit punctuation operators only after precedence specification, ambiguity analysis, and full cross-component matrices are ready.

Completed Track: Day 13 — Security and Error-Surface Hardening

Objective

Add comprehensive negative-path test coverage for all security subsystems and harden the error formatting surface.

Completed (2026-05-11)

• Security negative-path hardening matrix: 146 cases across path traversal, command injection, URL scheme validation, SQL injection, XSS payloads, ReDoS patterns, filename sanitization, permission boundary enforcement, taint-sink propagation (all 5 labels x all 8 sinks = 40 parametrized cases), CFI indirect-call checks, and memory safety (use-after-free, type confusion, bounds at boundary).
  • File: tests/unit/systems/test_security_negative_paths.py
• Security module bug fixes:
  • safe_execute now detects actual newline and carriage-return characters (not only their two-char escape representations).
  • is_safe_regex now detects (X+)+, (X*)*, (X|X)+, and (.*)+ ReDoS patterns.
  • File: src/nexuslang/security/utils.py
• Error-surface hardening matrix: 48 cases covering format_source_context resilience (OOB line/column, empty source, large context), all error class location fields in formatted output, NxlNameError "did you mean" matching edge cases, get_close_matches large-list cap, and suggest_correction completeness.
  • File: tests/unit/errors/test_error_surface_hardening.py
• CI extended with security-hardening job gating example-smoke and downstream jobs.

Exit Criteria Met

1. Existing security suite: 171 passed, 6 skipped.
2. New negative-path suite: 146 passed.
3. New error-surface suite: 48 passed.
4. Broad sweep (compiler + type_system + errors + systems): 2306 passed, 97 skipped, 1 xfailed, zero failures.

Completed Track: Linux inotify Resilience Hardening

Objective

Stabilize stdlib watcher and inotify validation under constrained host kernel limits without masking genuine product defects.

Completed (2026-05-11)

• Watcher lifecycle hardening in src/nexuslang/stdlib/fs_watch/init.py:
  • Added robust cleanup on startup failures to avoid partially-initialized observer resource leaks.
  • Added stronger shutdown behavior (unschedule_all, longer join timeout, explicit observer nulling).
  • Added process-exit cleanup (atexit) to stop residual watchers.
• fs-watch test hardening in tests/unit/stdlib/test_fs_watch.py:
  • Added host-capacity-aware skip path for ENOSPC/EMFILE inotify exhaustion conditions.
  • Added autouse watcher-registry hygiene fixture (fs_watch_stop_all before/after each test).
  • Updated start calls to use shared guarded helper.
  • Updated concurrent thread test to avoid raising pytest skip exceptions from worker threads.
• Raw inotify test hardening in tests/unit/stdlib/test_platform_linux.py:
  • Added guarded helpers for inotify_create and inotify_add_watch with skip-on-capacity exhaustion semantics.

Exit Criteria Met

1. Previously failing focus suites now stable: 19 passed, 48 skipped, 0 failed.
2. Broader stdlib sweep remains green: 2277 passed, 269 skipped, 0 failed.

Next Candidate Track

• Day 14 (Week 2 safety checkpoint): Compile and publish unresolved-risk register from Days 8-13. Update STATUS.md with baseline metrics. Identify any remaining open items for Week 3 tooling hardening.
• Optional follow-up: Add a dedicated CI job for Linux fs_watch/inotify resilience matrices so host-resource edge cases remain explicitly covered.