refactor(direction): centralize last paragraph isRtl reads on helper (SD-2778) (#3289)

* refactor(direction): centralize last paragraph isRtl reads on helper (SD-2778)

Migrate the two remaining direct reads of attrs.direction/.dir on the
paragraph inline-direction axis onto getParagraphInlineDirection:

- layout-bridge/src/position-hit.ts: isRtlBlock
- layout-resolved/src/resolveParagraph.ts: isRtl

Behavior is unchanged on the typed directionContext path and strictly
broader on fallback (the helper also covers paragraphProperties.rightToLeft).
After this, no consumer outside the helper reads the legacy scalar fields;
a follow-up can stop pm-adapter from writing them and drop them from
ParagraphAttrs.

* test(direction): pin SD-2778 migration via typed-path + broader-fallback cases

Two coverage gaps caught in review:

- layout-resolved/src/resolveLayout.test.ts ("preserves increasing
  first-line marker anchor for nested RTL list levels") used
  attrs.direction: 'rtl'. The pre-migration code read attrs.direction
  directly, so that fixture would have passed against the old
  implementation. Switch to directionContext.inlineDirection so the test
  only passes through the new helper-driven typed path.

- layout-bridge/test/position-hit.test.ts: switching isRtlBlock to
  getParagraphInlineDirection is strictly broader on fallback (the helper
  also picks up paragraphProperties.rightToLeft when no directionContext
  is present). Pin that case so the broadening is intentional and not a
  regression vector.

Author: caio-pizzol

packages/layout-engine/layout-bridge/src/position-hit.ts

@@ -23,7 +23,12 @@ import type {
   ParagraphBlock,
   ParagraphMeasure,
 } from '@superdoc/contracts';
-import { adjustAvailableWidthForTextIndent, computeLinePmRange, getFirstLineIndentOffset } from '@superdoc/contracts';
+import {
+  adjustAvailableWidthForTextIndent,
+  computeLinePmRange,
+  getFirstLineIndentOffset,
+  getParagraphInlineDirection,
+} from '@superdoc/contracts';
 import { charOffsetToPm, findCharacterAtX } from './text-measurement.js';
 import type { PageGeometryHelper } from './page-geometry-helper.js';
 
@@ -120,26 +125,9 @@ export const getAtomicPmRange = (fragment: AtomicFragment, block: FlowBlock): {
 
 export const isRtlBlock = (block: FlowBlock): boolean => {
   if (block.kind !== 'paragraph') return false;
-  const attrs = block.attrs as Record<string, unknown> | undefined;
-  if (!attrs) return false;
-  // AIDEV-NOTE: The typed directionContext.inlineDirection (SD-2776) is the source of
-  // truth for paragraph inline direction. Check the value, not the key — `inlineDirection`
-  // can be `undefined` per the resolver contract (no explicit w:bidi anywhere in the
-  // cascade), and we should fall through to the legacy field in that case.
   // Do NOT consult attrs.textDirection here: that's writing-mode (ECMA §17.18.93,
   // values lrTb/tbRl/btLr/lrTbV/tbRlV/tbLrV) which is a separate axis from inline RTL.
-  const directionContext = attrs.directionContext as { inlineDirection?: string } | undefined;
-  if (directionContext?.inlineDirection != null) {
-    return directionContext.inlineDirection === 'rtl';
-  }
-  // AIDEV-NOTE: compat-fallback — `attrs.direction` / `attrs.dir` are the legacy scalar
-  // duplicates of `directionContext.inlineDirection`. Retire once SD-2778 collapses
-  // them on `ParagraphAttrs`.
-  const directionAttr = attrs.direction ?? attrs.dir;
-  if (typeof directionAttr === 'string' && directionAttr.toLowerCase() === 'rtl') {
-    return true;
-  }
-  return false;
+  return getParagraphInlineDirection(block.attrs) === 'rtl';
 };
 
 export const determineColumn = (layout: Layout, fragmentX: number): number => {

packages/layout-engine/layout-bridge/test/position-hit.test.ts

@@ -61,4 +61,13 @@ describe('isRtlBlock', () => {
       ),
     ).toBe(true);
   });
+
+  // SD-2778: switching to getParagraphInlineDirection is strictly broader on
+  // fallback than the prior inline read. Specifically, the helper picks up
+  // paragraphProperties.rightToLeft when neither directionContext nor the legacy
+  // scalar field is present. Pin that case so the broader fallback is intentional.
+  it('falls back to paragraphProperties.rightToLeft when no other direction signal is present', () => {
+    expect(isRtlBlock(paragraph({ paragraphProperties: { rightToLeft: true } }))).toBe(true);
+    expect(isRtlBlock(paragraph({ paragraphProperties: { rightToLeft: false } }))).toBe(false);
+  });
 });

packages/layout-engine/layout-resolved/src/resolveLayout.test.ts

@@ -1777,7 +1777,12 @@ describe('resolveLayout', () => {
         id,
         runs: [{ kind: 'text', text: 'RTL list item' }],
         attrs: {
-          direction: 'rtl',
+          // SD-2778: use directionContext so this test only passes through the
+          // new helper-driven typed path. The pre-migration code read
+          // attrs.direction directly, so the prior `direction: 'rtl'` fixture
+          // would have passed against the old implementation too and didn't
+          // actually prove the migration.
+          directionContext: { inlineDirection: 'rtl', writingMode: 'horizontal-tb' },
           indent: { right, hanging: -24 },
           wordLayout: {
             marker: {

packages/layout-engine/layout-resolved/src/resolveParagraph.ts

@@ -9,7 +9,7 @@ import type {
   ResolvedDropCapItem,
   ResolvedListMarkerItem,
 } from '@superdoc/contracts';
-import { adjustAvailableWidthForTextIndent } from '@superdoc/contracts';
+import { adjustAvailableWidthForTextIndent, getParagraphInlineDirection } from '@superdoc/contracts';
 import {
   isMinimalWordLayout,
   resolveListMarkerGeometry,
@@ -93,7 +93,7 @@ export function resolveParagraphContent(
   const paraIndent = (block.attrs as ParagraphAttrs | undefined)?.indent;
   const paraIndentLeft = paraIndent?.left ?? 0;
   const paraIndentRight = paraIndent?.right ?? 0;
-  const isRtl = (block.attrs as ParagraphAttrs | undefined)?.direction === 'rtl';
+  const isRtl = getParagraphInlineDirection(block.attrs) === 'rtl';
   const {
     anchorIndentPx: paraMarkerAnchorIndent,
     firstLinePx: markerFirstLine,