From 3fe63fd5d980d9f7bcbccff20c74a181e60ee2b8 Mon Sep 17 00:00:00 2001
From: liyuqian <liyuqian@google.com>
Date: Wed, 18 Jul 2018 11:08:25 -0700
Subject: [PATCH] Add presubmit check for engine to flutter roll (#5790)

This prevents us from getting flutter far behind engine in the future.
The additional travis check will also stop the skia autoroller even
if we foget to turn it off.
---
 .travis.yml          |  1 +
 travis/check_roll.sh | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)
 create mode 100755 travis/check_roll.sh

diff --git a/.travis.yml b/.travis.yml
index 043404ff109..1364ad19322 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,6 +5,7 @@ sudo: false
 before_script:
   - ./travis/setup.sh
 script:
+  - ./travis/check_roll.sh
   - ./travis/format.sh
   - ./travis/build.sh
   - ./travis/test.sh
diff --git a/travis/check_roll.sh b/travis/check_roll.sh
new file mode 100755
index 00000000000..296300d3eae
--- /dev/null
+++ b/travis/check_roll.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+
+if git remote get-url upstream >/dev/null 2>&1; then
+  UPSTREAM=upstream/master
+else
+  UPSTREAM=master
+fi;
+
+FLUTTER_VERSION="$(curl -s https://raw.githubusercontent.com/flutter/flutter/master/bin/internal/engine.version)"
+BEHIND="$(git rev-list $FLUTTER_VERSION..$UPSTREAM --oneline | wc -l)"
+MAX_BEHIND=16 # no more than 4 bisections to identify the issue
+
+if [[ $BEHIND -le $MAX_BEHIND ]]; then
+  echo "OK, the flutter/engine to flutter/flutter roll is only $BEHIND commits behind."
+else
+  echo "ERROR: The flutter/engine to flutter/flutter roll is $BEHIND commits behind!"
+  echo "       It exceeds our max allowance of $MAX_BEHIND. Unless that this commit fixes the roll,"
+  echo "       please roll engine into flutter first before merging more commits into engine."
+  exit 1
+fi
+