From 592ed4ee90b74551008ff641da3161eec9e332a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adrien=20B=C3=A9raud?= <adrien.beraud@savoirfairelinux.com>
Date: Mon, 24 Dec 2018 15:50:41 -0500
Subject: [PATCH] op cache: don't call callback if no value

---
 src/op_cache.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/op_cache.h b/src/op_cache.h
index eaae29c2..7dc4419f 100644
--- a/src/op_cache.h
+++ b/src/op_cache.h
@@ -89,7 +89,9 @@ public:
 
     void addListener(size_t token, ValueCallback cb, Sp<Query> q, Value::Filter filter) {
         listeners.emplace(token, LocalListener{q, filter, cb});
-        cb(cache.get(filter), false);
+        auto cached = cache.get(filter);
+        if (not cached.empty())
+            cb(cached, false);
     }
 
     bool removeListener(size_t token, const time_point& now) {