mustfail 'tag name in tag is wrong' \
refs/tags/$tagpfx/wombat:refs/tags/$tagpfx/$version $push_spec1
+echo ====
+badcommit=$(
+ git cat-file commit HEAD | \
+ perl -pe 's/^committer.*\n//' | \
+ git hash-object -w -t commit --stdin
+)
+git checkout -b broken $badcommit
+prep unstable sid
+mktag
+mustfail "corrupted object $badcommit" $push_spec
+
+git checkout dgit/sid
prep unstable sid
mktag
mustsucceed $push_spec # succeeds