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Josh Creek
86a597f0f5
Client now sends the last 4 ticks' actions per packet (newest-first, already-supported by net_codec's wire format from Phase 1) instead of a single action with no redundancy. Server gains a real per-slot ring buffer (new InputJitterBuffer class, scripts/input_jitter_buffer.gd) that consumes exactly one sequence number per physics tick: repeats the last action on a starve, zeroes only after a sustained 500ms stall, and reports real input_buffer_depth/last_input_seq/echo_client_send_ms in every snapshot instead of the hardcoded zeros Phase 2 shipped with. InputJitterBuffer is a standalone, scene-free RefCounted (same pattern as net_codec.gd/net_interpolator.gd) specifically so it's unit-testable against scripted arrival traces (tests/cases/test_input_jitter_buffer.gd): sequential consumption, redundancy surviving a 3-packet burst loss (3.1's own acceptance criterion), starvation repeat-then-zero timing, stale/ reordered packet handling, buffered-depth reporting, and ring-wraparound slot-tagging safety. One real bug found wiring this into a live match: the server's ring buffer started counting its own "expected sequence" from 0 the instant a player's slot was created - well before that player's first real packet could possibly have arrived (connection handshake, arena/ship spawn all take real time first). Since both sides only ever advance monotonically with no resync mechanism, that gap between the server's arbitrary local counter and the client's actual from-1 sequence numbers never closed, so the ship simply never received the client's input (0m movement in a two-process test). Fixed by seeding the buffer's expected-sequence counter from the client's own numbering on first real ingest, rather than assuming a shared from-zero baseline. Verified with real two-process runs: clean baseline movement restored, zero starvation observed under 25% random simulated input loss (well above what redundancy-4 needs to fully absorb), and correct starve-then- stall behaviour confirmed under 100% loss as a sanity check that the mechanism isn't a silent no-op. Full regression suite, including the net-sim-latency milestone gate, re-run clean.