From ac488fd45f9a077c6f5ab3e7b8e7f9fe005d65b7 Mon Sep 17 00:00:00 2001
From: Elliott Jin <elliott.jin@gmail.com>
Date: Sun, 19 Mar 2017 13:18:10 -0700
Subject: [PATCH] tools: Don't lint in pre-commit hook if no files changed.

---
 tools/pre-commit | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/pre-commit b/tools/pre-commit
index 617b6294cb..14ea067e68 100755
--- a/tools/pre-commit
+++ b/tools/pre-commit
@@ -9,11 +9,17 @@
 # contains your provisioned Zulip development environment, the linter
 # will automatically be run through `vagrant ssh`.
 
+changed_files=$(git diff --cached --name-only --diff-filter=ACM)
+if [ -z "$changed_files" ]; then
+    echo "No changed files to lint."
+    exit 0
+fi
+
 if [ -z "$VIRTUAL_ENV" ] && `which vagrant > /dev/null` && [ -e .vagrant ]; then
-    vcmd='/srv/zulip/tools/lint-all --pep8 --force $(cd /srv/zulip && git diff --cached --name-only --diff-filter=ACM) || true'
+    vcmd="/srv/zulip/tools/lint-all --pep8 --force $changed_files || true"
     echo "Running lint-all using vagrant..."
     vagrant ssh -c "$vcmd"
 else
-    ./tools/lint-all --pep8 --force $(git diff --cached --name-only --diff-filter=ACM) || true
+    ./tools/lint-all --pep8 --force $changed_files || true
 fi
 exit 0