From 1888708ca52b5d5e4a15546055ccb7799d616e2d Mon Sep 17 00:00:00 2001
From: Seuf <seuf76@gmail.com>
Date: Tue, 8 May 2018 14:04:20 +0200
Subject: [PATCH] Templating : return __empty__ value when all value return
 nothing to prevent elasticsearch syntaxe error (#9701)

---
 public/app/features/templating/template_srv.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/public/app/features/templating/template_srv.ts b/public/app/features/templating/template_srv.ts
index e7c1dc7f102..99a9f53d547 100644
--- a/public/app/features/templating/template_srv.ts
+++ b/public/app/features/templating/template_srv.ts
@@ -74,6 +74,9 @@ export class TemplateSrv {
     if (typeof value === 'string') {
       return luceneEscape(value);
     }
+    if (value instanceof Array && value.length === 0) {
+        return '__empty__';
+    }
     var quotedValues = _.map(value, function(val) {
       return '"' + luceneEscape(val) + '"';
     });