fix(search): fan out only over values the leaf can read

packages/search/src/project.ts

@@ -927,23 +927,52 @@ function tuplesOf(
   const identity = field.ref.identity;
   const weldable = nestedType.fields
     .filter((nested) => nested.filterable === true || nested.name === identity)
-    .map((nested) => irAlias(nestedType, nested))
-    // A leaf the frame carries at most one value for is already a tuple
-    // position; splitting it would copy the node to no purpose.
-    .filter((alias) => valuesOf(node, alias).length > 1);
+    .map((nested) => ({ nested, alias: irAlias(nestedType, nested) }))
+    // A leaf the frame carries at most one READABLE value for is already a
+    // tuple position; splitting it would copy the node to no purpose.
+    .filter(({ nested, alias }) => splittable(node, alias, nested).length > 1);
   if (weldable.length === 0) {
     return [node];
   }
   let tuples: FramedNode[] = [node];
-  for (const alias of weldable) {
-    const values = valuesOf(node, alias);
+  for (const { nested, alias } of weldable) {
+    const values = splittable(node, alias, nested);
     tuples = tuples.flatMap((tuple) =>
       values.map((value) => ({ ...tuple, [alias]: value })),
     );
   }
   return tuples;
 }
 
+/**
+ * The framed values of one leaf that fan-out may split on: those the field can
+ * actually READ.
+ *
+ * A leaf reads its own kind of value and passes over the rest: a `keyword`
+ * takes literals and ignores an IRI stated beside them, which real data does –
+ * a role named both as a string and as a Wikidata entity on one node.
+ * Splitting on a value the leaf then reads nothing from mints an entry the leaf
+ * is absent from – the same endpoint, apparently in no role at all, shown to a
+ * reader and matched by a filter. So the split follows the reader.
+ *
+ * `keyword` is the only kind that needs narrowing. A `text` field has no filter
+ * operator (`filterOperatorFor`), so nothing welds it and it is never a tuple
+ * position. A `reference` is, and both of its shapes are meaningful: an IRI,
+ * and – for a {@link ReferenceStrategy.local local} lookup – a node the graph
+ * named inline, which has no IRI and is a referent all the same.
+ */
+function splittable(
+  node: FramedNode,
+  alias: string,
+  field: SearchField,
+): readonly unknown[] {
+  const values = valuesOf(node, alias);
+  if (field.kind === 'keyword') {
+    return values.filter((value) => literalString(value) !== undefined);
+  }
+  return values;
+}
+
 // --- Framed-IR readers: read a field’s value off the framed node by its
 // {@link irAlias IR Alias} key. Internal to projection – a `derive` reads the
 // projected document, never the node, so `path` stays the whole statement of

packages/search/test/qualified-relation.test.ts

@@ -318,6 +318,34 @@ describe('fanning an edge out into one entry per tuple', () => {
     expect(entries).toEqual([{ role: 'etser' }]);
   });
 
+  it('splits only on values the leaf can read', () => {
+    // Real data states a role both as a string and as a Wikidata entity on one
+    // node. A `keyword` leaf reads literals and passes over the IRI, so
+    // splitting on it would mint an entry the role is absent from – the same
+    // endpoint, apparently in no role at all, shown to a reader and matched by
+    // a filter.
+    const tagged = {
+      '@id': 'https://ex/work/16',
+      [workKey('creator')]: [
+        {
+          [edgeKey('role')]: [
+            { '@value': 'fotograaf' },
+            { '@id': 'http://www.wikidata.org/entity/Q33231' },
+          ],
+          [edgeKey('creator')]: [
+            { '@id': 'https://a/1', [personKey('sameAs')]: [{ '@id': RKD }] },
+          ],
+        },
+      ],
+    };
+    const entries = entriesOf(
+      projectDocument(tagged, work, searchSchema(work, person, weldableEdge)),
+    );
+
+    expect(entries).toHaveLength(1);
+    expect(entries[0].role).toBe('fotograaf');
+  });
+
   it('treats the identity field as a tuple position', () => {
     // Nothing welds the identity field by name, but the flat companion
     // harvested from it is the leaf a weld uses to name the endpoint. An entry

packages/search/vite.config.ts

@@ -12,7 +12,7 @@ export default mergeConfig(
         thresholds: {
           functions: 100,
           lines: 100,
-          branches: 99.71,
+          branches: 99.72,
           statements: 100,
         },
       },