From d6b1f4946f930b825371579fa9c84bfc591d73f3 Mon Sep 17 00:00:00 2001
From: Patrick Valsecchi <patrick.valsecchi@camptocamp.com>
Date: Tue, 1 May 2018 16:46:31 +0200
Subject: [PATCH] Fix crssync crash during build

On my machine, crssync dies with a core dump during the build of QGIS.
Infinite loop because there is no color defined in the scheme it loads.
---
 src/core/qgscolorschemeregistry.cpp | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/core/qgscolorschemeregistry.cpp b/src/core/qgscolorschemeregistry.cpp
index 85a1874659c..d6ccf9551b0 100644
--- a/src/core/qgscolorschemeregistry.cpp
+++ b/src/core/qgscolorschemeregistry.cpp
@@ -117,12 +117,15 @@ void QgsColorSchemeRegistry::setRandomStyleColorScheme( QgsColorScheme *scheme )
   {
     mRandomStyleColors = scheme->fetchColors();
 
-    std::random_device rd;
-    std::mt19937 mt( rd() );
-    std::uniform_int_distribution<int> colorDist( 0, mRandomStyleColors.count() - 1 );
-    mNextRandomStyleColorIndex = colorDist( mt );
-    std::uniform_int_distribution<int> colorDir( 0, 1 );
-    mNextRandomStyleColorDirection = colorDir( mt ) == 0 ? -1 : 1;
+    if ( mRandomStyleColors.count() > 0 )
+    {
+      std::random_device rd;
+      std::mt19937 mt( rd() );
+      std::uniform_int_distribution<int> colorDist( 0, mRandomStyleColors.count() - 1 );
+      mNextRandomStyleColorIndex = colorDist( mt );
+      std::uniform_int_distribution<int> colorDir( 0, 1 );
+      mNextRandomStyleColorDirection = colorDir( mt ) == 0 ? -1 : 1;
+    }
   }
   else
   {