vampire-like/openspec/changes/archive/2026-04-02-remove-simulationworld-legacy-movement-shims/specs/simulationworld-runtime-convergence/spec.md

MODIFIED Requirements

Requirement: SimulationWorld SHALL be the sole battle simulation executor

The battle runtime MUST execute movement, projectile stepping, collision broad-phase, and related simulation state updates through SimulationWorld, and it MUST NOT route these responsibilities through an alternative non-SimulationWorld runtime path or expose compatibility switches that imply such a runtime path still exists.

Scenario: Battle tick advances through SimulationWorld

• WHEN the battle update loop advances a gameplay frame
• THEN SimulationWorld executes the simulation pipeline for that frame as the authoritative runtime update path

Scenario: Legacy routing switch does not select an alternate executor

• WHEN runtime configuration related to simulation movement is evaluated
• THEN it does not select or re-enable a separate legacy movement execution path

Scenario: Runtime API does not expose legacy movement enablement shims

• WHEN gameplay runtime code integrates with movement simulation
• THEN it does not depend on compatibility members whose purpose is to report whether SimulationWorld movement is enabled

Requirement: Runtime surfaces SHALL reflect the single-path architecture

Runtime debug surfaces, automated tests, architecture documents, and compatibility-facing runtime APIs MUST reflect that the project supports one authoritative SimulationWorld execution path rather than dual-path behavior, and MUST NOT preserve legacy solver provider abstractions that imply an alternate runtime separation path is still supported.

Scenario: Debug panel omits legacy solver controls

• WHEN runtime simulation debugging is displayed
• THEN it shows current SimulationWorld metrics without exposing legacy solver switching or dual-path controls

Scenario: Regression tests validate observable single-path behavior

• WHEN simulation regression coverage is maintained
• THEN tests validate observable outcomes such as movement, projectile lifetime, hit results, and hide/remove lifecycle instead of asserting private compatibility fields for legacy paths

Scenario: Runtime codebase omits legacy solver provider abstractions

• WHEN enemy separation behavior is implemented or documented
• THEN it is described as SimulationWorld-owned runtime behavior without referencing EnemySeparationSolverProvider, IEnemySeparationSolver, or equivalent legacy provider abstractions