Getting "Parent filter should not be sent when the schema is nested" when using parent filter in fl in solr 8

Question

I am trying to fetch the parent document with child documents. But getting "Parent filter should not be sent when the schema is nested" error.

Attached the query in below that I have tried but I can't get the solution

q : {!parent which=content_type:person}
fl : *, [child parentFilter=content_type:person]

Below is the document that I have added to solr core.

   Collection<SolrInputDocument> batch = new ArrayList<>();
   // Parent Doc 1, a person mamed John Jones
    SolrInputDocument person1 = new SolrInputDocument();
    person1.addField( "id",            "john_jones" );
    person1.addField( "content_type",  "person"     );
    // "_t" suffix tells Solr that it's text
    person1.addField( "first_name_t",  "John"       );
    person1.addField( "last_name_t",   "Jones"      );
    // states and history used in edismax examples
    person1.addField( "states_t",      "California Nevada Idaho Maine" );
    person1.addField( "history_t",     "safe accident accident accident accident accident" );

    // child docs, the vehicles he owns
    SolrInputDocument p1_car1 = new SolrInputDocument();
    p1_car1.addField( "id",            "jj_car1"    );
    p1_car1.addField( "content_type",  "car"        );
    // For cars "make" is an alias for "manufacturer"
    p1_car1.addField( "make_t",        "Honda"      );
    p1_car1.addField( "model_t",       "Accord"     );

    SolrInputDocument p1_car2 = new SolrInputDocument();
    p1_car2.addField( "id",            "jj_car2"    );
    p1_car2.addField( "content_type",  "car"        );
    p1_car2.addField( "make_t",        "Nissan"     );
    p1_car2.addField( "model_t",       "Maxima"     );

    SolrInputDocument p1_bike1 = new SolrInputDocument();
    p1_bike1.addField( "id",           "jj_bike1"   );
    p1_bike1.addField( "content_type", "bike"       );
    p1_bike1.addField( "make_t",       "Yamaha"     );
    p1_bike1.addField( "model_t",      "Passion"    );

    SolrInputDocument p1_bike2 = new SolrInputDocument();
    p1_bike2.addField( "id",           "jj_bike2"   );
    p1_bike2.addField( "content_type", "bike"       );
    p1_bike2.addField( "make_t",       "Peugeot"    );
    p1_bike2.addField( "model_t",      "Vivacity"   );

    // Add children to parent
    person1.addChildDocument( p1_car1  );
    person1.addChildDocument( p1_car2  );
    person1.addChildDocument( p1_bike1 );
    person1.addChildDocument( p1_bike2 );

    // Add parent to batch
    batch.add( person1 );


    // Parent Doc 2, person mamed Satish Smith
    SolrInputDocument person2 = new SolrInputDocument();
    person2.addField( "id",           "satish_smith" );
    person2.addField( "content_type", "person"       );
    person2.addField( "first_name_t", "Satish"       );
    person2.addField( "last_name_t",  "Smith"        );
    person2.addField( "states_t",     "California Texas California Maine Vermont Connecticut" );
    person2.addField( "history_t",    "safe safe safe safe safe safe safe safe accident" );

    // Vehicles (child docs)
    SolrInputDocument p2_car1 = new SolrInputDocument();
    p2_car1.addField( "id",            "ss_car1"     );
    p2_car1.addField( "content_type",  "car"         );
    p2_car1.addField( "make_t",        "Peugeot"     );
    p2_car1.addField( "model_t",       "iOn"         );
    SolrInputDocument p2_bike1 = new SolrInputDocument();
    p2_bike1.addField( "id",           "ss_bike1"    );
    p2_bike1.addField( "content_type", "bike"        );
    p2_bike1.addField( "make_t",       "Honda"       );
    p2_bike1.addField( "model_t",      "Spree"       );
    // link objects and add to batch
    person2.addChildDocument( p2_car1  );
    person2.addChildDocument( p2_bike1 );
    batch.add( person2 );

    System.out.println( "Adding batch of " + batch.size() + " parent docs" );

    // Submit as a group
    patientSolrClient.add( batch );
    patientSolrClient.commit()

Answer 1

I was getting same error , and tried all the possibilities described in tutorials, but later i found my managed-schema.xml had a duplicate entry of this.

Auto generated Script:

<fieldType name="_nest_path_" class="solr.NestPathField" 
maxCharsForDocValues="-1" omitNorms="true" omitTermFreqAndPositions="true" stored="false" />

Another one manually added by me:

<fieldType name="_nest_path_" type = "_nest_path_" />

I removed my entry then it started working fine.