[libvirt PATCH] scripts: avoid error in DCO check on empty branches

[Daniel P. Berrangé]

If the DCO check is run on an empty branch (ie one which has no commits
different from master), it throws an error due to trying to interpret
the empty string as a git commit SHA.

Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
---
 scripts/require-dco.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/scripts/require-dco.py b/scripts/require-dco.py
index 9fe13823a9..ae94393319 100755
--- a/scripts/require-dco.py
+++ b/scripts/require-dco.py
@@ -46,7 +46,10 @@ print("\nChecking for 'Signed-off-by: NAME <EMAIL>' on all commits since %s...\n
 log = subprocess.check_output(["git", "log", "--format=%H %s", ancestor + "..."],
                               universal_newlines=True)
 
-commits = [[c[0:40], c[41:]] for c in log.strip().split("\n")]
+if log == "":
+    commits = []
+else:
+    commits = [[c[0:40], c[41:]] for c in log.strip().split("\n")]
 
 for sha, subject in commits:
 
-- 
2.24.1