# Session 0044.0 — Transcript

> App: vscode-cowriting-plugin
> Start: 2026-06-13T07-40 (PST)
> Type: planning-and-executing
> End: 2026-06-13T08-04 (PST)
> Status: **FINALIZED.**
> Posture: autonomous (yolo)

## Launch prompt

```
/goal plan-and-execute #47 (SLICE-2 of the document-edit flow — document edits propose per changed block: diffToBlockHunks INV-39 supersedes INV-37, word-precise intra-block attribution INV-40, block-insertion anchoring INV-41), per specs/coauthoring-document-edit-flow.md

```

## Plan

**SLICE-2 — #47 (review, P1)** of the document-edit flow
(`specs/coauthoring-document-edit-flow.md` §7.2). Anchor: Feature #47
(`type/feature`); covered by the graduated combined Solution Design → §4.3 R3.

Document rewrites propose **one F4 proposal per changed block** (the unit a human
reviews), but each accept reconciles attribution at **word** granularity (the unit
F3 records). INV-39 supersedes INV-37 for document edits; INV-40 word-precise
intra-block attribution; INV-41 block-insertion anchoring. Selection edits
unchanged.

Tasks:
1. `model.ts` — add optional `granularity?: "block" | "single"` to `Proposal`
   (additive, back-compat: absent ⇒ `"single"`). INV-39/§6.3.
2. `proposalModel.ts` — `addProposal` opts gains `granularity`, threaded onto the
   proposal (omitted when absent).
3. `trackChangesModel.ts` — new pure `diffToBlockHunks(currentText,
   rewrittenText): EditHunk[]`: split both sides into the existing block units
   (`splitBlocksWithRanges` for source ranges + `splitBlocks` keys), diff blocks
   (reuse `diffArrays` keying like `diffBlocks`), emit ONE `EditHunk` per
   changed/added/removed block — changed → `[block.start,end)`→rewrite; fences
   atomic (whole-fence hunk); inserted → anchored to adjacent boundary (INV-41,
   reuse the `anchorInsertion` idea); unchanged → none. Same `EditHunk` shape as
   `diffToHunks` (which is RETAINED as the intra-block sub-diff engine).
4. `trackChangesPreview.ts` — `runEditAndPropose` **document branch** uses
   `diffToBlockHunks` and tags each minted proposal `granularity:"block"`.
5. `proposalController.ts` — `accept`: when `granularity === "block"`, re-resolve
   the block text, `diffToHunks(blockText, replacement)` → per-run word sub-diff,
   apply **one `applyAgentEdit` per changed run, descending offset** so only the
   runs Claude changed land Claude-attributed; unchanged spans keep prior author
   (INV-40). Non-block keeps the single `applyAgentEdit`.
6. Tests: unit (`diffToBlockHunks` + INV-40 controller) + host E2E (#47 cases in
   §6.8); update the existing f11 document-path E2E (now per-block, supersedes
   INV-37 word-level expectation); `docs/MANUAL-SMOKE-F12.md` §2.

**Design note (seam constraint):** `pendingEdits.matchEvent` resolves ONE
registration per change event, so INV-40's per-run attribution is implemented as
**sequential** `applyAgentEdit` calls (descending offset), not a single
multi-replace `WorkspaceEdit`. The spec's "one undo-grouped edit" wording is thus
approximated as N undo steps per block accept — see Deferred decisions.

No new persisted artifact; no deploy pipeline (VS Code extension).

## Results

**SLICE-2 (#47, review, P1) shipped to `main`** — PR
[#50](https://git.benstull.org/benstull/vscode-cowriting-plugin/pulls/50)
(merged), issue #47 closed.

- `trackChangesModel.ts` — new pure `diffToBlockHunks` (block-key alignment via
  `diffArrays`/`diffBlocks` keying; isolated changed block → block-aligned hunk →
  rewritten raw; fences atomic INV-23; insert/delete → exact gap-span hunk;
  zero-width gap-span anchored INV-41). Split `diffToHunks` into raw
  `wordEditHunks` + anchoring wrapper (fixes a latent overlap bug under batch apply).
- `trackChangesPreview.ts` — document branch uses `diffToBlockHunks`, tags
  `granularity:"block"`.
- `model.ts`/`proposalModel.ts` — additive optional `Proposal.granularity`.
- `proposalController.ts` — `acceptBlock`: intra-block word sub-diff
  (`wordEditHunks`) → one `applyAgentEdit` per changed run, descending offset
  (INV-40 word-precise attribution; unchanged spans keep prior author).
- Tests: `diffToBlockHunks` unit (reconstruction/fence/add-remove); `f12Review`
  host E2E (M→M, unchanged→none, fence atomic, INV-40, INV-41); updated f11
  document-path E2E to per-block; `MANUAL-SMOKE-F12.md` §2.

Verification: `tsc --noEmit` clean; **214 unit** green; **69/5 host E2E** green
(main suite 65 → 69 net with the new F12 review tests).

**Next:** SLICE-3 — #46 (accept-all, INV-42): `acceptAllProposals` (controller,
descending-order, orphan-skip + report) + `cowriting.acceptAllProposals` command
+ preview toolbar **Accept all** button (`{type:"acceptAll"}` intent, shown ≥2
pending).

## Session arc

1. **Claim.** Resumed via `/goal next` (after session 0043 shipped #42); claimed
   session 0044 for #47. Clean `main` baseline.
2. **Anchor gate.** #47 (`type/feature`) covered by the graduated combined design
   → §4.3 R3 satisfied.
3. **Deep code read.** `splitBlocks*`/`diffBlocks`/`diffToHunks`/`EditHunk`,
   `runEditAndPropose`, `proposalController.accept`/`applyAgentEdit`, and crucially
   `pendingEdits.matchEvent` (one registration per change event → drove the INV-40
   sequential-apply decision).
4. **TDD `diffToBlockHunks`.** First attempt (coarsen word-hunks) failed a
   reconstruction case — discovered `diffToHunks` can emit OVERLAPPING hunks
   (anchorInsertion over-absorbs). Switched to block-key alignment with
   replacement-from-rewritten-raw → green.
5. **Model + wiring + INV-40 accept.** Added `granularity`; document branch →
   `diffToBlockHunks`; `acceptBlock` intra-block sub-diff. The overlap bug then
   resurfaced in `acceptBlock` (batch apply) → split `diffToHunks` into raw
   `wordEditHunks` (disjoint) + anchoring wrapper; `acceptBlock` uses raw → green.
6. **Verified + shipped** (214 unit, 69/5 E2E), self-reviewed, PR #50 merged,
   #47 closed, memory + transcript updated.

## Deferred decisions

_Autonomous-mode low-confidence calls the driver made and would have
liked operator input on. Appended as the session runs; surfaced at
finalize. Empty if none._

- **INV-40 undo granularity** (driver call). Spec §6.2/§6.7 say accepting a block
  proposal should be "one undo-grouped WorkspaceEdit." But the F3 seam's
  `pendingEdits.matchEvent` matches exactly ONE registration per change event, so a
  single `WorkspaceEdit` with N independent run-replaces can't carry per-run
  attribution (the multi-hunk event fails to match any single registration → falls
  through to human). Implemented INV-40 as **sequential per-run `applyAgentEdit`
  calls, descending offset** — correct word-precise attribution, reuses the seam
  with zero attribution-core risk, but a block accept is N undo steps rather than
  one. Single-undo-step would require extending `matchEvent`/`onDidChange` to
  consume multiple registrations per event (riskier F3 change) — left as a possible
  follow-up.