Requires internals of libmongoc, replace example-client.c

mark-unknown-repro.c

#include <mongoc/mongoc.h>
#include <stdio.h>
#include <stdlib.h>
#include <mongoc/mongoc-cursor-private.h>
#include <mongoc/mongoc-client-private.h>
#include <mongoc/mongoc-topology-private.h>

int
main (int argc, char *argv[])
{
   mongoc_client_pool_t *pool;
   mongoc_uri_t *uri;

   mongoc_init();
   uri = mongoc_uri_new ("mongodb://localhost:27017/?retryWrites=false&retryReads=false");
   pool = mongoc_client_pool_new (uri);

   mongoc_client_t *client = mongoc_client_pool_pop (pool);
   bson_t empty_doc = BSON_INITIALIZER;
   mongoc_cursor_t *cursor;
   mongoc_collection_t *collection;
   mongoc_read_concern_t *rc;
   const bson_t *doc;
   bson_error_t error;

   collection = mongoc_client_get_collection (client, "test", "test");
   rc = mongoc_read_concern_new ();
   mongoc_read_concern_set_level (rc, MONGOC_READ_CONCERN_LEVEL_MAJORITY);
   mongoc_collection_set_read_concern (collection, rc);

   printf ("initializing agg, this ties cursor to the server, but does not send the command\n");
   cursor = mongoc_collection_aggregate (collection, MONGOC_QUERY_NONE, &empty_doc, NULL /* opts */, NULL /* read_prefs */);
   if (mongoc_cursor_error (cursor, &error)) {
      printf ("agg error: %s\n", error.message);
   }

   printf ("simulating a server being marked as UNKNOWN\n");
   mongoc_topology_invalidate_server (client->topology, cursor->server_id, &error);
   printf ("done\n");
   
   printf ("sending aggregate command\n");
   mongoc_cursor_next (cursor, &doc);
   if (mongoc_cursor_error (cursor, &error)) {
      printf ("error: %s\n", error.message);
   }

   bson_destroy (&empty_doc);
   mongoc_cursor_destroy (cursor);
   mongoc_collection_destroy (collection);
   mongoc_client_pool_push (pool, client);
   
   mongoc_client_pool_destroy (pool);
   mongoc_uri_destroy (uri);
   mongoc_cleanup();
}