Broad Bun Suite Health Fix

Goal

Make the broad Bun package-graph sweep honest again after the non-React coverage passes.

Scope

• Reproduce the shared failure in the broad Bun package-graph run.
• Find the first real shared root cause instead of blaming random product files.
• Fix the smallest honest seam.
• Re-run the broad Bun sweep plus build-first verification for touched packages.

Phase Plan

• [completed] Reproduce the broad Bun failure and narrow the first shared culprit
• [completed] Fix the first shared suite-health root cause
• [completed] Re-run the broad Bun sweep
• [completed] Run build, typecheck, lint, and capture reusable learning

Findings

• The first broad failure presents as editor.tf being undefined inside SlateExtensionPlugin.ts.
• That symptom is misleading.
• getLinkAttributes.spec.ts passes alone and fails only when paired with floatingLinkTriggers.spec.ts.
• That makes the current first culprit test pollution, not a random product regression.
• useTableMergeState.spec.tsx was the second poison pill: it replaced the whole ../../lib barrel with a partial mock surface.
• useElementStore.spec.tsx was still dumping expected USE_ELEMENT_CONTEXT warnings into the broad run because the spec harness used the default debug logger.

Outcome

• Broad Bun package-graph sweep is green again.
• The product code in SlateExtensionPlugin was not the root cause.
• The actual fix was test-harness cleanup:
  • floatingLinkTriggers.spec.ts now spies on platejs.getEditorPlugin instead of mocking all of platejs
  • useTableMergeState.spec.tsx now spies on platejs/react and ../../lib exports instead of replacing whole modules
  • useElementStore.spec.tsx now overrides DebugPlugin in the test editor so warning-path coverage stays quiet

Verification

• Repro combo:
  • bun test packages/link/src/react/utils/getLinkAttributes.spec.ts packages/link/src/react/utils/floatingLinkTriggers.spec.ts
• Table pair:
  • bun test packages/table/src/react/components/TableCellElement/setSelectedCellsBorder.spec.tsx packages/table/src/react/hooks/useTableMergeState.spec.tsx
• Package slice:
  • bun test packages/table/src
• Broad sweep:
  • bun test packages/link/src packages/markdown/src packages/core/src packages/autoformat/src packages/basic-nodes/src packages/table/src packages/list-classic/src packages/suggestion/src
• Noise cleanup:
  • bun test packages/core/src/react/stores/element/useElementStore.spec.tsx
• Build-first gate:
  • pnpm install
  • pnpm turbo build --filter=./packages/link --filter=./packages/table
  • pnpm turbo typecheck --concurrency=1 --filter=./packages/link --filter=./packages/table
  • pnpm lint:fix

Learning

• Shared package mocks should be local spies, not partial Bun module replacements. See 2026-03-25-shared-package-mocks-should-be-local-spies-not-partial-bun-module-replacements.md.
• Warning-path React specs should capture debug.warn in their harness. See 2026-03-25-warning-path-react-specs-should-capture-debug-warn-in-their-harness.md.