fix(anki): preserve one-sided Senren furigana

src/anki-integration/field-grouping-merge.test.ts

@@ -394,7 +394,7 @@ test('Senren merge closes unclosed group spans so later scenes stay siblings', a
   assert.equal(openTags, closeTags);
 });
 
-test('computeFieldGroupingMergedFields clears SentenceFurigana when either note lacks it', async () => {
+test('Kiku merge clears SentenceFurigana when either note lacks it', async () => {
   const { collaborator } = createCollaborator();
 
   const merged = await collaborator.computeFieldGroupingMergedFields(
@@ -411,3 +411,21 @@ test('computeFieldGroupingMergedFields clears SentenceFurigana when either note
 
   assert.equal(merged.SentenceFurigana, '');
 });
+
+test('Senren merge keeps duplicate SentenceFurigana when the kept field is empty', async () => {
+  const { collaborator } = createCollaborator({ fieldGroupingProvider: 'senren' });
+
+  const merged = await collaborator.computeFieldGroupingMergedFields(
+    300,
+    200,
+    makeNote(300, {
+      SentenceFurigana: '',
+    }),
+    makeNote(200, {
+      SentenceFurigana: 'duplicate furigana',
+    }),
+    false,
+  );
+
+  assert.equal(merged.SentenceFurigana, '<span class="group">duplicate furigana</span>');
+});

src/anki-integration/field-grouping-merge.ts

@@ -162,8 +162,11 @@ export class FieldGroupingMergeCollaborator {
       if (!existingValue.trim() && !newValue.trim()) continue;
 
       if (keepFieldNormalized === 'sentencefurigana') {
+        const hasBothValues = existingValue.trim().length > 0 && newValue.trim().length > 0;
+        const usesSenrenGrouping =
+          this.deps.getEffectiveSentenceCardConfig().fieldGroupingProvider === 'senren';
         mergedFields[keepFieldName] =
-          existingValue.trim() && newValue.trim()
+          hasBothValues || usesSenrenGrouping
             ? this.applyFieldGrouping(
                 existingValue,
                 newValue,