Phase 1 / Etch / Time subsystem and timers

[guysenpai]

Brief: briefs/M1.0.13-time-and-timers.md

Closing notes

• Delivered (E1→E6, each gate GO'd on the pushed diff). every/after_unscaled graduated (quantize stays reserved, fail-loud re-pointed at a later Sequencer-adjacent milestone); TimerKind/TimerStmt AST slab; timer_stmt parses (unbound at statement head + let-bound in parseLetStmt, the spawn precedent; mut/annotation rejected); TimerHandle builtin type (cancel() only, not awaitable, non-POD field-rejected), timer arg typed as a full Duration expression, timer body enforced as a synchronous context (E0901); pub const builtin_resources descriptor table in types.zig (GameTime/UnscaledTime/RealTime, fixed_dt = 1/60) consumed by the checker (ambient get(GameTime).dt, no when gate) and by interp.zig Pass A (TagSet injection point, idempotent hot-reload, accumulators re-seeded from surviving totals); stepOnce time population (dt/total/frame/fixed_frame; unscaled/real unaffected by time_scale/paused); await wait/await wait_unscaled re-plumbed onto the game/unscaled clocks (literal-only restriction kept for both); async_tick demoted to the frame counter; runtime timer registry (monotone pointer-stable + husk, scope snapshot at scheduling, firing at the tick head in registration order, every re-armed at a fixed period, cancel() idempotent with a mid-fire latch, Value.timer_handle bound in the parent scope after the snapshot).
• Byte-identity at time_scale = 1: proven by the untouched M1.0.11/12 tick-precise tests (the 60-tick wait test is the explicit witness); realized by the tick-unit accumulator representation — see Recorded deviations (accepted at the E5 review; §9.12 reconciled KB-side by Guy).
• Files touched beyond the per-file list (both justified in the Execution log, within src/etch/): value.zig (timer_handle — the E6 deliverable Value.timer_handle; duration — runtime Duration seconds so after(d) takes a variable; eql arms) and the .duration_lit arm in evalExpr.
• Fix-as-you-go: the M1.0.11 partition test's wait_unscaled half retired (it graduates here; the remaining boundary is entity_event, M1.0.14); two stale M1.0.12 token-test assertions on the reserved timer family removed at E1; test-narration comments "wake at async_tick N" renamed to "wake at game clock N" (same values at scale = 1); one stale future-tense M1.0.13 comment rewritten as the byte-identity witness note.
• §3.6.1 audits: language audit clean — the only French hits on the branch diff are verbatim quotes of the spec section title "Les trois temps" (engine-gameplay-systems.md), the FROZEN brief's own citation convention. Drift audit clean after the comment patches above; no orphaned references to the timer fail-loud, the reserved timer family, or the wait_unscaled partition remain in src//tools//tests/.
• Residuals (scope boundaries, not debt): quantize (Sequencer-adjacent milestone), time.* stdlib sugar (+ the deferred etch-stdlib.md §20 reconciliation), dt rule-parameter injection, per-entity TimeDilation/selective pause/WorldClock, lifting wait's literal-only restriction, Phase-2 bytecode lowering.
• Validation: full suite green in debug and ReleaseSafe at every gate and at close; zig build, zig fmt --check, zig build lint green; no benchmarks required. CLAUDE.md §3.4 updated on the branch (docs(claude-md): update for M1.0.13).

Validation checklist (Étape 4)

• All Scope deliverables present (E1→E6, gate-by-gate GO on the pushed diffs)
• No drift into Out of scope (quantize reserved; wait/wait_unscaled stay literal-only; no time.* sugar, no dt param, no scheduler features)
• All Acceptance-criteria tests green in debug and ReleaseSafe
• Benchmarks: none required
• Observable behavior demonstrable (E6 inline tests: after(d) at the exact tick, time_scale = 0.5 stretch, pause freeze vs after_unscaled, same-tick emit visibility)
• zig build, zig build test (debug + ReleaseSafe), zig fmt --check, zig build lint green
• CLAUDE.md §3.4 updated and committed on the branch (docs(claude-md): update for M1.0.13)
• Language audit (§3.6.1) passed — branch diff + brief free of French prose (verbatim "Les trois temps" spec-title quotes only)
• Local drift audit (§3.6.1) passed — orphans patched (async_tick wake comments, stale future-tense M1.0.13 note) or noted in Closing notes
• Closing notes filled
• Brief Status: CLOSED, Closed: 2026-07-04
• Final commit docs(brief): close M1.0.13

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