Fix internal when calling connection.subscribe with the same name twice (Issue #1718)

Author: sharadraju

doc/src/release_notes.rst

@@ -40,7 +40,7 @@ Thin Mode Changes
 
 #)  Added connection optimization feature which uses
     Server Name Indication (SNI) extension of the TLS protocol.
- 
+
 #)  Added support for setting the :attr:`~oracledb.edition` when connecting to
     the database.
 
@@ -53,6 +53,13 @@ Thin Mode Changes
 Thick Mode Changes
 ++++++++++++++++++
 
+#)  Fixed internal error that occurs while running ``connection.subscribe()``
+    with same name for second time.
+    See `Issue #1718 <https://github.com/oracle/node-oracledb/issues/1718>`__.
+
+#)  Fixed internal error that occurs while running ``connection.subscribe()`` with
+    sql reading from non-existent tables.
+
 #)  Internal error handling improvements.
 
 node-oracledb `v6.7.1 <https://github.com/oracle/node-oracledb/compare/v6.7.0...v6.7.1>`__ (23 Dec 2024)

src/njsConnection.c

@@ -2359,6 +2359,8 @@ NJS_NAPI_METHOD_IMPL_ASYNC(njsConnection_subscribe, 2, NULL)
     if (valueType == napi_external) {
         NJS_CHECK_NAPI(env, napi_get_value_external(env, args[0],
                 (void**) &baton->subscription))
+        NJS_CHECK_NAPI(env, napi_create_reference(env, args[0], 1,
+                &baton->jsSubscriptionRef))
     } else {
         if (!njsSubscription_new(baton, env))
             return false;

src/njsSubscription.c

@@ -1,4 +1,4 @@
-// Copyright (c) 2018, 2022, Oracle and/or its affiliates.
+// Copyright (c) 2018, 2025, Oracle and/or its affiliates.
 
 //-----------------------------------------------------------------------------
 //
@@ -268,7 +268,8 @@ static bool njsSubscription_createMessageTable(napi_env env,
 void njsSubscription_eventHandler(njsSubscription *subscr,
         dpiSubscrMessage *incomingMessage)
 {
-    if (subscr->handle) {
+    // handle is valid and listening notifications is enabled.
+    if (subscr->handle && subscr->notifications) {
         uv_mutex_lock(&subscr->mutex);
         uv_barrier_init(&subscr->barrier, 2);
         subscr->message = incomingMessage;
@@ -428,7 +429,6 @@ bool njsSubscription_startNotifications(njsSubscription *subscr,
     if (!subscr->notifications) {
 
         // keep the name on the subscription
-        subscr->notifications = true;
         baton->name = NULL;
         baton->nameLength = 0;
 
@@ -438,6 +438,7 @@ bool njsSubscription_startNotifications(njsSubscription *subscr,
         uv_async_init(loop, &subscr->async,
                 njsSubscription_processNotification);
         subscr->async.data = subscr;
+        subscr->notifications = true;
 
     }