git reflog expire --expire=all the_symref
'
+test_expect_success 'continue walking past root commits' '
+ git init orphanage &&
+ (
+ cd orphanage &&
+ cat >expect <<-\EOF &&
+ HEAD@{0} commit (initial): orphan2-1
+ HEAD@{1} commit: orphan1-2
+ HEAD@{2} commit (initial): orphan1-1
+ HEAD@{3} commit (initial): initial
+ EOF
+ test_commit initial &&
+ git reflog &&
+ git checkout --orphan orphan1 &&
+ test_commit orphan1-1 &&
+ test_commit orphan1-2 &&
+ git checkout --orphan orphan2 &&
+ test_commit orphan2-1 &&
+ git log -g --format="%gd %gs" >actual &&
+ test_cmp expect actual
+ )
+'
+
test_done