SOLR-18039: Support repeated parents.preFilter in KnnQParser (#4139)

Signed-off-by: Arup Chauhan <arupchauhan.connect@gmail.com>

Author: arup-chauhan

changelog/unreleased/parents-prefilter-multi-value.yml

@@ -0,0 +1,9 @@
+# See https://github.com/apache/solr/blob/main/dev-docs/changelog.adoc
+title: Support repeated parents.preFilter values in nested vector knn queries
+type: fixed # added, changed, fixed, deprecated, removed, dependency_update, security, other
+authors:
+  - name: Arup Chauhan
+    nick: arup-chauhan
+links:
+  - name: SOLR-18039
+    url: https://issues.apache.org/jira/browse/SOLR-18039

solr/core/src/java/org/apache/solr/search/vector/KnnQParser.java

@@ -133,10 +133,11 @@ public Query parse() throws SyntaxError {
     final Integer filteredSearchThreshold = localParams.getInt(FILTERED_SEARCH_THRESHOLD);
 
     // check for parent diversification logic...
-    final String parentsFilterQuery = localParams.get(PARENTS_PRE_FILTER);
+    final String[] parentsFilterQueries = localParams.getParams(PARENTS_PRE_FILTER);
     final String allParentsQuery = localParams.get(CHILDREN_OF);
 
-    boolean isDiversifyingChildrenKnnQuery = null != parentsFilterQuery || null != allParentsQuery;
+    boolean isDiversifyingChildrenKnnQuery =
+        null != parentsFilterQueries || null != allParentsQuery;
     if (isDiversifyingChildrenKnnQuery) {
       if (null == allParentsQuery) {
         throw new SolrException(
@@ -150,7 +151,7 @@ public Query parse() throws SyntaxError {
       final BitSetProducer allParentsBitSet =
           BlockJoinParentQParser.getCachedBitSetProducer(
               req, subQuery(allParentsQuery, null).getQuery());
-      final BooleanQuery acceptedParents = getParentsFilter(parentsFilterQuery);
+      final BooleanQuery acceptedParents = getParentsFilter(parentsFilterQueries);
 
       Query acceptedChildren =
           getChildrenFilter(getFilterQuery(), acceptedParents, allParentsBitSet);
@@ -183,14 +184,19 @@ public Query parse() throws SyntaxError {
         filteredSearchThreshold);
   }
 
-  private BooleanQuery getParentsFilter(String parentsFilterQuery) throws SyntaxError {
+  private BooleanQuery getParentsFilter(String[] parentsFilterQueries) throws SyntaxError {
     BooleanQuery.Builder acceptedParentsBuilder = new BooleanQuery.Builder();
-    if (parentsFilterQuery != null) {
-      final Query parentsFilter = subQuery(parentsFilterQuery, null).getQuery();
-      acceptedParentsBuilder.add(parentsFilter, BooleanClause.Occur.FILTER);
+    if (parentsFilterQueries != null) {
+      for (String parentsFilterQuery : parentsFilterQueries) {
+        final QParser parser = subQuery(parentsFilterQuery, null);
+        parser.setIsFilter(true);
+        final Query parentsFilter = parser.getQuery();
+        if (parentsFilter != null) {
+          acceptedParentsBuilder.add(parentsFilter, BooleanClause.Occur.FILTER);
+        }
+      }
     }
-    BooleanQuery acceptedParents = acceptedParentsBuilder.build();
-    return acceptedParents;
+    return acceptedParentsBuilder.build();
   }
 
   private Query getChildrenFilter(

solr/core/src/test/org/apache/solr/search/join/BlockJoinNestedVectorsQParserTest.java

@@ -229,6 +229,23 @@ public void parentRetrievalFloat_knnChildrenWithParentFilter_shouldReturnKnnPare
         "//result/doc[3]/str[@name='id'][.='2']");
   }
 
+  @Test
+  public void parentRetrievalFloat_knnChildrenWithMultipleParentFilters_shouldReturnKnnParents() {
+    assertQ(
+        req(
+            "q", "{!parent which=$allParents score=max v=$children.q}",
+            "fl", "id,score",
+            "children.q",
+                "{!knn f=vector topK=3 parents.preFilter=$parentFilter1 parents.preFilter=$parentFilter2 childrenOf=$allParents}"
+                    + FLOAT_QUERY_VECTOR,
+            "allParents", "parent_s:[* TO *]",
+            "parentFilter1", "parent_s:(a c)",
+            "parentFilter2", "parent_s:(c e)"),
+        "//*[@numFound='2']",
+        "//result/doc[1]/str[@name='id'][.='8']",
+        "//result/doc[2]/str[@name='id'][.='2']");
+  }
+
   @Test
   public void
       parentRetrievalFloat_knnChildrenWithParentFilterAndChildrenFilter_shouldReturnKnnParents() {