git-rewrite-authors: add sanity check for missing authors file

diff --git a/.bin/git-rewrite-authors b/.bin/git-rewrite-authors
index e136e59876d54c26796bd02294c868c6f3c2649b..4e4c2bf8b112d9659434834894ecb366d74fdb5e 100755 (executable)
--- a/.bin/git-rewrite-authors
+++ b/.bin/git-rewrite-authors
@@ -22,6 +22,10 @@ for x in cvs-authors authors ; do
                exit 1
        fi
 done
+if [ ! -e "${author_file}" ] ; then
+       echo "error: could not find ${author_file}"
+       exit 1
+fi
 git filter-branch \
        --env-filter ". ${tmp};"' \
                eval `decode "${GIT_AUTHOR_NAME}" AUTHOR`; \