Slate v2 Core Editor Method Regression Sweep

Goal

Sweep .tmp/slate-v2/packages/slate/src/editor/** for methods with the same failure class as insertBreak: manual structural rewrites that bypass the primitive seam that already owns selection, nested containers, merge/split semantics, transactions, commits, or command middleware.

Constraints

• Source truth is current .tmp/slate-v2, compared against legacy ../slate.
• Prefer fixes that route through editor primitives and existing transform seams.
• Do not revive Transforms.* as public API.
• Do not create a second transaction, commit, or history model.
• If a concrete same-class bug is found, add a focused behavior test before the fix when practical.

Review Checklist

• Inventory all core editor methods and legacy equivalents.
• Classify methods by risk: query-only, thin primitive wrapper, exact operation helper, structural rewrite.
• Inspect structural rewrites for nested block, inline, void, mark, selection, and transaction target drift.
• Fix any concrete P0/P1 regression found during the sweep.
• Run focused package tests and relevant type/lint checks.

Findings

• packages/slate/src/transforms-text/delete-text.ts: concrete same-class regression risk. The collapsed cross-block delete helper had a private mergeBlocksAtPoint implementation that manually merged block children and cleaned ancestors. That duplicated the mergeNodes seam that already owns nested container, id preservation, and selection rebasing behavior. Replaced it with mergeNodes(editor, { at: point, hanging: true, voids }).
• packages/slate/src/transforms-node/lift-nodes.ts: concrete same-class ownership leak. liftNodeAtPath accepted an optional transaction and fell back to editor.apply; one range branch called it without the active tx. Made the helper require tx and routed every operation through tx.apply.
• packages/slate/src/editor/insert-text.ts: stale-target preflight smell. The read-only/void ignore guard checked command.options?.at ?? Editor.getLiveSelection(editor) before transaction target resolution. Moved the guard behind tx.resolveTarget({ at }) so implicit selection-sensitive writes use the transaction-resolved target.
• Static guard found no remaining matches in packages/slate/src/editor, packages/slate/src/transforms-node, or packages/slate/src/transforms-text for direct editor.apply, optional tx apply fallback, stale shouldIgnoreTarget preflight, or Transforms.*.
• Broad snapshot-contract.ts and transaction-contract.ts still contain older direct-write rows that now trip the write-boundary guard. Those are existing test-suite migration debt, not failures introduced by this sweep.

Verification

• bun test ./packages/slate/test/primitive-method-runtime-contract.ts --bail 1 passed.
• bun test ./packages/slate/test/transforms-contract.ts -t "liftNodes" --bail 1 passed after updating the row to use editor.update.
• bun test ./packages/slate/test/snapshot-contract.ts -t "adjacent nested block boundaries" --bail 1 passed.
• bun test ./packages/slate/test/write-boundary-contract.ts --bail 1 passed.
• bunx turbo build --filter=./packages/slate --force passed.
• bunx turbo typecheck --filter=./packages/slate --force passed.
• bun run lint:fix passed.
• bun run lint passed.
• rg -n "editor\\.apply\\(|\\bapply\\s*=\\s*tx\\?|shouldIgnoreTarget\\(editor, (command\\.options|requestedTarget|Editor\\.getLiveSelection)|Transforms\\." packages/slate/src/editor packages/slate/src/transforms-node packages/slate/src/transforms-text returned no matches.

Residual Risk

• The largest remaining correctness surface is still delete-text and fragment insertion around deeply nested/void/inline combinations. The sweep removed the obvious duplicate merge path, but exhaustive confidence still depends on the generated editor-method gauntlets.
• Full-file snapshot-contract.ts and transaction-contract.ts need a separate test modernization pass to wrap legacy direct writes in editor.update or replace them with current public contracts.

Progress

• 2026-04-26: Started sweep after insertBreak nested code-block regression. Loaded prior Slate v2 learnings on transform hard cuts, wrapper preservation, cross-block delete merge seam, structural key ownership, and apply/onChange hard cuts.
• 2026-04-26: Completed core sweep for the same regression class. Patched delete cross-block merge routing, lift-node transaction ownership, and insert-text target freshness. Added/updated focused contracts and verified package build/type/lint.
• 2026-04-26: Compounding check found high overlap with the existing cross-block delete merge-seam learning. Updated that learning with the editor-method sweep guard instead of creating a duplicate solution doc.