---
 Completion/Unix/Command/_git |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/Completion/Unix/Command/_git b/Completion/Unix/Command/_git
index 8416542..e513e16 100644
--- a/Completion/Unix/Command/_git
+++ b/Completion/Unix/Command/_git
@@ -1539,7 +1539,7 @@ __git_zstyle_default
':completion::complete:git-branch:delete-argument-rest:*' i
 (( $+functions[__git_is_treeish] )) ||
 __git_is_treeish () {
   local sha1
-  sha1="$(git rev-parse $1)"
+  sha1="$(git rev-parse $1 -- 2> /dev/null)" &&
   [[ "$(git cat-file -t "${sha1}^{tree}" 2> /dev/null)" == tree ]]
 }


-- 
Mikael Magnusson