demo-workspace-eastl-feature

Prompt file imported from hlucianojr1/ea-logic-copilot-workshop-code (.github/prompts/demo-workspace-eastl-feature.prompt.md). Copyright stays with the author.

Objective

Stage the specs and empty implementation directories for the EASTL-based feature that Sessions 6 (Spec-Kit Pt 1) and 7 (Spec-Kit Pt 2) build to. The actual .h/.cpp/test sources are produced during the live session by /implement invocations — that's the demo. Pre-creating the dirs ensures /implement has a stable target.

Context references

• #file:../instructions/spec-kit-artifacts.instructions.md
• #file:../instructions/cpp-snippets.instructions.md
• #file:../../docs/engagement-charter.md

Pre-conditions

• demo-workspace-scaffold.prompt.md and demo-workspace-engine-module.prompt.md completed.
• spec-kit Constitution authored (will be done by demo-workspace-spec-kit-init.prompt.md).

Steps

1. specs/specs/lockless-ring-buffer.md — feature spec following spec-kit-artifacts.instructions.md format:
   • Motivation: SPSC ring-buffer for telemetry events, allocator-aware, deterministic.
   • Public API sketch — header excerpt in cpp fence (must compile, no exceptions, no RTTI).
   • Invariants: capacity is power of two; try_push/try_pop are wait-free; no allocations after construction.
   • Test contract: list 6 named tests under tests/util/lockless_ring_buffer_test.cpp.
   • Risks: false sharing, ABA on size_t counters, allocator lifetime.
2. specs/specs/fixed-string.md — feature spec:
   • Motivation: small-string optimization with compile-time max length, no heap.
   • Public API: template<size_t N> class fixed_string.
   • Invariants: capacity is N; push_back past capacity is a logged error (no exception).
   • Test contract: list 5 named tests under tests/util/fixed_string_test.cpp.
   • Risks: alignment for SIMD-friendly access, char-encoding (ASCII only for v1).
3. Create empty include/engine_demo/util/, src/util/, tests/util/ directories with .gitkeep so the path is stable for later /implement runs.

Output contract

• Two spec files exist, each with the eight required spec sections.
• Three util/ subdirectories exist with .gitkeep.
• No production source files yet — those come from spec-kit /implement.

Self-validation

grep -q "## Test contract" output/ea-cpp-games/specs/specs/lockless-ring-buffer.md
grep -q "## Test contract" output/ea-cpp-games/specs/specs/fixed-string.md
test -d output/ea-cpp-games/include/engine_demo/util

Failure modes

• Pre-implementing the feature: do NOT generate .h/.cpp here — that defeats the Session 6/7 demo. The feature is born during the live /implement.
• Spec without test contract: every spec must name its tests; no exceptions.