Repository navigation
M3: success-path buffering and defensive-copy allocations (V28 V29) — benchmark-gated, rides #23 #29
Description
Source: multi-agent review of PR #26, adversarial verification (both PLAUSIBLE — mechanisms real, impact unproven at current volume). 2026-08-14. M-anchor: M3 runway, gated on the performance baselines and executed with (or immediately after) the #23 adapter-boundary redesign — V28 corroborates #23's P3 with the current cursor-list surface.
- V28 · Successful list responses are fully materialized as UTF-16 strings before System.Text.Json parses them (
Pipelinebuffers viaReadAsStringAsync; success adapters parse and discard). A success-only UTF-8 path avoids body-size-linear allocation. This is the same mechanism family as M3: union deserialization single-pass redesign + streaming adapter boundary (P1 P5 P3) — benchmark-gated #23/P3 — fold, do not duplicate. - V29 · Internally deserialized pages are copied again by the public response's defensive-copy init accessor (DTO collection →
Array.AsReadOnly([.. value])), an avoidable O(n) copy when ownership is already internal. Any fix must keep ADR-0004's defensive-copy contract for consumer-constructed instances — the fast path may only apply to the internal already-owned handoff (the forgiven-null error-path precedent shows the emitter can special-case the internal constructor).
Benchmarks decide (repo rule: performance claims are settled by benchmarks, never by argument); before/after numbers ride the PR.
Activity
docs(agents): hand off the M2 close-out — Q91 research, fix batch, me…
Blind-Striker commentedon Aug 20, 2026
Completed by Arc 6 source fa6124d, hosted green in run 32374393085 on Linux, Windows, and macOS. V28 now has a generated success-only UTF-8 byte path, preserving charset/BOM and malformed-UTF-8 replacement fallbacks while leaving API-error RawBody string buffering intact. Same-environment allocation moved GetMessage 21.91 -> 19.15 KB and ListMessages 22.60 -> 19.81 KB; timings improved from 45.970 -> 39.728 us and 46.859 -> 43.593 us respectively. Health stayed effectively flat in allocation (2.08 -> 2.05 KB) and receives no speed claim. V29s defensive-copy premise had already been retired by ADR-0014/#55; the current generated IReadOnly collections remain shallow and uncopied. The Q108 comparison also rejected immutable generated collections on total cost, so PublicApi remains unchanged.