[kriszyp]

📝 Summary

Qualify the residency transport guarantee: capable peers receive invalidations. Peers without learned residencyStubCopy support can receive the legacy stub put. Excluded peers still follow normal routing. An equal-version resident full row skips the legacy stub.

A holder’s versioned answer settles a read immediately, whether live or a deletion. Only unversioned empties require every listed non-self holder to answer, with at least one empty. The text covers legacy stub empties. It explicitly excludes cross-holder version comparison and quorum/read-repair reads.

🤔 Cross-repository coordination

Pro #1087 already merged the copy gate and heading, so that compatibility correction needs no new runtime. The read-answer wording accompanies the Pro not-resident change for #436; its draft will link here. Review’s repeated claim that #1087 must land first is obsolete.

✅ Verification

PR QA: skipped @ 2363d48 — documentation only

• npm run check:design-docs passes; formatting passes.
• Documentation only; no runtime behavior changes or end-to-end route.
• Prior-head CI: Linux unit jobs on Node 22/24/26 fail on both this PR and current main. The Node 24 logs match at unitTests/resources/evictionBlobs.test.js:164 ('read' == 'merged'); all other checks completed successfully or were skipped.

Refs HarperFast/harper-pro#436.

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Release target: v5.4 — documents the compatibility gate introduced with the residency fixes.

Related PRs: #3322 overlaps, #3375 overlaps
Complexity: easy

_{Review-Coverage: authored=codex; ran=gemini,claude,cursor-composer; adjudicated=domain; declined=cursor-grok,muse; rounds=5; full=2 @ 2363d48}

_{Review-Attention: skim ~1m @ 2363d48}

[gemini-code-assist]

Code Review

This pull request updates the resources/DESIGN.md file to document the transport invariant's legacy base-copy fallback behavior for peers without residencyStubCopy or whose capabilities are not yet learned. The review feedback suggests formatting "an invalidation" as invalidate for consistency and using straight apostrophes for "stub's", "request's", and "resident's" to match the document's style.

[gemini-code-assist]

For consistency with the preceding sentence ("A capable peer receives invalidate"), "an invalidation" should be formatted as the code-font operation/message name invalidate. Additionally, straight apostrophes should be used for "stub's", "request's", and "resident's" to match the style of the rest of the document.

Suggested change

Transport invariant: a stub is never sent, served, or stored as a complete record through harper-pro GET_RECORD and its copy sender, except the legacy base-copy fallback for a peer without `residencyStubCopy` or whose capabilities are not yet learned. For a peer listed in the stub’s residency (or with no residency list), that fallback sends the stored projection as an ordinary `put`; a receiver without the row stores it as complete. A capable peer receives `invalidate`. Excluded peers still receive an invalidation or are skipped under id-based residency. See harper-pro's `replication/DESIGN.md`, Send-side residency. This does not cover the separate relocate-on-read path or the explicit local `replicateFrom: false` policy. `loadLocalRecord`, `ensureLoaded`, and full-record query materialization propagate residency loader errors; only a successful empty response means absence. A successful instance load advances the request’s last-modified version to the resident’s version.

Transport invariant: a stub is never sent, served, or stored as a complete record through harper-pro GET_RECORD and its copy sender, except the legacy base-copy fallback for a peer without `residencyStubCopy` or whose capabilities are not yet learned. For a peer listed in the stub's residency (or with no residency list), that fallback sends the stored projection as an ordinary `put`; a receiver without the row stores it as complete. A capable peer receives `invalidate`. Excluded peers still receive an `invalidate` or are skipped under id-based residency. See harper-pro's `replication/DESIGN.md`, Send-side residency. This does not cover the separate relocate-on-read path or the explicit local `replicateFrom: false` policy. `loadLocalRecord`, `ensureLoaded`, and full-record query materialization propagate residency loader errors; only a successful empty response means absence. A successful instance load advances the request's last-modified version to the resident's version.

[kriszyp]

invalidation is a prose description here; the adjacent sentences name the invalidate operation. The paragraph already uses typographic apostrophes for request’s and resident’s on main, and the formatting check passes. Leaving these cosmetic choices unchanged.

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