fix(jni): free QueryResult on Arrow entry-point failure

The four Arrow JNI entry points (createArrowTable, createArrowRelTable,
createArrowRelTableCSR, dropArrowTable) freed only their wrapper on
failure. The C API's setQueryResult (ladybug/src/c_api/connection.cpp:77)
releases the C++ QueryResult into the out-param *before* checking success,
so on the setQueryResult failure branch the out-param owned a QueryResult
that the wrapper's delete did not touch and lbug_query_result_destroy
was not called.

Linear leak of ~432 bytes per failed call, verified by RSS measurement in
issue #13.

Call lbug_query_result_destroy(queryResult) before delete on the failure
branch of all four. lbug_query_result_destroy is null-safe and a no-op
when setQueryResult did not run, so this is safe for both the
setQueryResult and the catch-block failure modes.

Closes #13

Author: adsharma

src/jni/lbug_java.cpp

@@ -853,6 +853,10 @@ JNIEXPORT jobject JNICALL Java_com_ladybugdb_Native_lbugConnectionCreateArrowTab
         auto state = lbug_connection_create_arrow_table(conn, table.c_str(), schema, arrays,
             static_cast<uint64_t>(numArrays), queryResult);
         if (state != LbugSuccess) {
+            // The C API can release a QueryResult into the out-param before
+            // reporting failure (see Connection::setQueryResult). The wrapper
+            // does not own it, so `delete` alone would leak.
+            lbug_query_result_destroy(queryResult);
             delete queryResult;
             throwLastError(env, "Failed to create Arrow table");
             return jobject();
@@ -880,6 +884,10 @@ JNIEXPORT jobject JNICALL Java_com_ladybugdb_Native_lbugConnectionCreateArrowRel
         auto state = lbug_connection_create_arrow_rel_table(conn, table.c_str(), srcTable.c_str(),
             dstTable.c_str(), schema, arrays, static_cast<uint64_t>(numArrays), queryResult);
         if (state != LbugSuccess) {
+            // The C API can release a QueryResult into the out-param before
+            // reporting failure (see Connection::setQueryResult). The wrapper
+            // does not own it, so `delete` alone would leak.
+            lbug_query_result_destroy(queryResult);
             delete queryResult;
             throwLastError(env, "Failed to create Arrow relationship table");
             return jobject();
@@ -919,6 +927,10 @@ JNIEXPORT jobject JNICALL Java_com_ladybugdb_Native_lbugConnectionCreateArrowRel
             static_cast<uint64_t>(numIndicesArrays), indptrSchema, indptrArrays,
             static_cast<uint64_t>(numIndptrArrays), dstColumnPtr, queryResult);
         if (state != LbugSuccess) {
+            // The C API can release a QueryResult into the out-param before
+            // reporting failure (see Connection::setQueryResult). The wrapper
+            // does not own it, so `delete` alone would leak.
+            lbug_query_result_destroy(queryResult);
             delete queryResult;
             throwLastError(env, "Failed to create Arrow CSR relationship table");
             return jobject();
@@ -940,6 +952,10 @@ JNIEXPORT jobject JNICALL Java_com_ladybugdb_Native_lbugConnectionDropArrowTable
         auto* queryResult = new lbug_query_result();
         auto state = lbug_connection_drop_arrow_table(conn, table.c_str(), queryResult);
         if (state != LbugSuccess) {
+            // The C API can release a QueryResult into the out-param before
+            // reporting failure (see Connection::setQueryResult). The wrapper
+            // does not own it, so `delete` alone would leak.
+            lbug_query_result_destroy(queryResult);
             delete queryResult;
             throwLastError(env, "Failed to drop Arrow table");
             return jobject();