Script to check whether a branch is up to date

.travis.yml

@@ -1,6 +1,7 @@
 language: c
 
 before_install:
+  - ./check-up-to-date-with-master.sh
   - sudo apt-get -y install python-pip
 
   - sudo apt-get -y install python-software-properties

check-up-to-date-with-master.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+# Add remote-master
+git remote add -t master remote-master https://github.com/CartoDB/crankshaft.git
+
+# Fetch master reference
+git fetch --depth=1 remote-master master
+
+# Compare HEAD with master
+# NOTE: travis by default uses --depth=50 so we are actually checking that the tip
+# of the branch is no more than 50 commits away from master as well.
+git rev-list HEAD | grep $(git rev-parse remote-master/master) ||
+    { echo "Your branch is not up to date with latest release";
+      echo "Please update it by running the following:";
+      echo "    git fetch && git merge origin/develop";
+      false; }