CCBC-1636: deallocate old packet when updating collection ID

mcreq_renew_packet() requires the caller to deallocate original copy,
otherwise the memory will be only released by pipeline destructor.

Change-Id: I833c19313c96bcc3b785f414f55938eb8d3d2e64
Reviewed-on: https://review.couchbase.org/c/libcouchbase/+/206375
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: Michael Reiche <michael.reiche@couchbase.com>

Author: avsej

src/mc/mcreq.c

@@ -288,7 +288,7 @@ static mc_PACKET *check_collection_id(mc_PIPELINE *pipeline, mc_PACKET *packet)
             if (collection_id_length == 0) {
                 // but collection id prefix was not encoded, we should assume default collection and prepend zero as
                 // a collection identifier
-                packet = mcreq_set_cid(packet, 0);
+                packet = mcreq_set_cid(pipeline, packet, 0);
             }
             break;
 
@@ -698,10 +698,13 @@ static void mcreq_set_cid_field(mc_PACKET *packet, uint32_t cid)
     packet->flags |= MCREQ_F_HASCID;
 }
 
-mc_PACKET *mcreq_set_cid(mc_PACKET *packet, uint32_t cid)
+mc_PACKET *mcreq_set_cid(mc_PIPELINE *pipeline, mc_PACKET *packet, uint32_t cid)
 {
     if ((packet->flags & MCREQ_F_DETACHED) == 0) {
-        packet = mcreq_renew_packet(packet);
+        mc_PACKET *copy = mcreq_renew_packet(packet);
+        mcreq_wipe_packet(pipeline, packet);
+        mcreq_release_packet(pipeline, packet);
+        packet = copy;
     }
     mcreq_set_cid_field(packet, cid);
     return packet;

src/mc/mcreq.h

@@ -705,7 +705,7 @@ uint32_t mcreq_get_size(const mc_PACKET *packet);
 
 uint32_t mcreq_get_cid(lcb_INSTANCE *instance, const mc_PACKET *packet, int *cid_set);
 
-mc_PACKET *mcreq_set_cid(mc_PACKET *packet, uint32_t cid);
+mc_PACKET *mcreq_set_cid(mc_PIPELINE *pipeline, mc_PACKET *packet, uint32_t cid);
 
 /**
  * @brief Get the vBucket for the request

src/mcserver/mcserver.cc

@@ -299,9 +299,10 @@ bool Server::handle_unknown_collection(MemcachedResponse &resp, mc_PACKET *oldpk
     wrapper.pkt = mcreq_renew_packet(oldpkt);
     wrapper.instance = instance;
     wrapper.timeout = LCB_NS2US(MCREQ_PKT_RDATA(wrapper.pkt)->deadline - now);
-    auto operation = [orig_status](const lcb_RESPGETCID *, packet_wrapper *wrp) {
+    mc_PIPELINE *pipeline{this};
+    auto operation = [orig_status, pipeline](const lcb_RESPGETCID *, packet_wrapper *wrp) {
         if ((wrp->pkt->flags & MCREQ_F_NOCID) == 0) {
-            wrp->pkt = mcreq_set_cid(wrp->pkt, wrp->cid);
+            wrp->pkt = mcreq_set_cid(pipeline, wrp->pkt, wrp->cid);
         }
         /** Reschedule the packet again .. */
         wrp->pkt->flags &= ~MCREQ_STATE_FLAGS;