only run p4 print if necessary

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>

diff --git a/contrib/fast-import/git-p4 b/contrib/fast-import/git-p4
index 63d7a4c995dfd27f599da409f94c3e2b9246e56c..76bbe3fdbfd30f6fdeb32a76837a3faa4be5c88d 100755 (executable)
--- a/contrib/fast-import/git-p4
+++ b/contrib/fast-import/git-p4
@@ -677,6 +677,9 @@ class P4Sync(Command):
         specs = [(f['path'] + "#" + f['rev'], f)  for f in files
                  if f['action'] != 'delete']
 
+        if not specs:
+            return
+
         data = read_pipe('p4 print %s' % ' '.join(['"%s"' % path
                                                    for (path, info) in specs]))