Print git-diff when pre-commit fails

When pre-commit fails and automatically fixes issues for us in Jenkins
we are not able to see what pre-commit automatically fixed. Adding
--show-diff-on-failure makes pre-commit perform a git-diff immediately
after failing to ensure more useful output is printed to inform the
contributor what changes are needed to pass the check.

Change-Id: Ia4dc73f6a6b044fd75705fb6985a49419a3014cb
Signed-off-by: Thanh Ha <zxiiro@gmail.com>

diff --git a/tox.ini b/tox.ini
index 87e40692f98cb2e0cd0aadde0ca4c4170a48022e..2be422d1a1f6e8c0350a3b8bbfbc827a9fe1d0f5 100644 (file)
--- a/tox.ini
+++ b/tox.ini
@@ -32,7 +32,7 @@ basepython = python3
 deps = pre-commit
 commands =
     pre-commit install --hook-type commit-msg
-    pre-commit run --all-files
+    pre-commit run --all-files --show-diff-on-failure
 
 [testenv:prefix]
 commands = python {toxinidir}/check_prefix.py