From ba266efd6a8ebf1a853d7dcc6543991205bcf2db Mon Sep 17 00:00:00 2001
From: Robert Varga <rovarga@cisco.com>
Date: Tue, 25 Oct 2016 19:11:40 +0200
Subject: [PATCH] BUG-6522: do not accidentally grow lists

If we end up with an empty collection being passed in,
do not do any processing so we do not inflate lists
unnecessarily. In profiling this showed to waste as
much as 23MiB of memory.

Change-Id: Ibb47953894162e6658f473ca763f17b8a98d2cb2
Signed-off-by: Robert Varga <rovarga@cisco.com>
---
 .../yang/parser/stmt/reactor/StatementContextBase.java    | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/stmt/reactor/StatementContextBase.java b/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/stmt/reactor/StatementContextBase.java
index f9247a4753..45bf701a1a 100644
--- a/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/stmt/reactor/StatementContextBase.java
+++ b/yang/yang-parser-impl/src/main/java/org/opendaylight/yangtools/yang/parser/stmt/reactor/StatementContextBase.java
@@ -128,6 +128,10 @@ public abstract class StatementContextBase<A, D extends DeclaredStatement<A>, E
 
     @Override
     public void addAsEffectOfStatement(final Collection<StatementContextBase<?, ?, ?>> ctxs) {
+        if (ctxs.isEmpty()) {
+            return;
+        }
+
         if (effectOfStatement.isEmpty()) {
             effectOfStatement = new ArrayList<>(ctxs.size());
         }
@@ -319,6 +323,10 @@ public abstract class StatementContextBase<A, D extends DeclaredStatement<A>, E
      *             if statement parameter is null
      */
     public void addEffectiveSubstatements(final Collection<StatementContextBase<?, ?, ?>> substatements) {
+        if (substatements.isEmpty()) {
+            return;
+        }
+
         substatements.forEach(Preconditions::checkNotNull);
         beforeAddEffectiveStatement(substatements.size());
         effective.addAll(substatements);
-- 
2.36.6