Add linting pre-push hook (#5154)

CONTRIBUTING.rst

@@ -18,7 +18,9 @@ To contribute a patch:
    harder to merge in a large change with a lot of disjoint features.
 2. Submit the patch as a GitHub pull request against the master branch.
 3. Make sure that your code passes the unit tests.
-4. Add new unit tests for your code.
+4. Make sure that your code passes the linter. Run setup_hooks.sh to create
+   a git hook that will run the linter before you push your changes.
+5. Add new unit tests for your code.
 
 .. _`ray-dev@googlegroups.com`: https://groups.google.com/forum/#!forum/ray-dev
 .. _`GitHub Issues`: https://github.com/ray-project/ray/issues

hooks/pre-push

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+echo "Linting changes as part of pre-push hook"
+echo ""
+echo "ci/travis/format.sh:"
+ci/travis/format.sh
+
+lint_exit_status=$?
+if [ $lint_exit_status -ne 0 ]; then
+	echo ""
+	echo "Linting changes failed."
+	echo "Please make sure 'ci/travis/format.sh'"\
+		"runs with no errors before pushing."
+	echo "If you want to ignore this and push anyways,"\
+		"re-run with '--no-verify'."
+	exit 1
+fi
+exit 0

setup_hooks.sh

@@ -0,0 +1,2 @@
+#!/bin/bash
+ln -s $PWD/hooks/pre-push $PWD/.git/hooks/pre-push