Đoàn Trần Công Danh [off-list ref] writes:
+test_expect_success 'mailinfo warn CR in base64 encoded email' '
+ sed "s/%%/$(printf \\015)/" "$DATA/quoted-cr-msg" >expect-cr-msg &&
+ sed "s/%%/$(printf \\015)/" "$DATA/quoted-cr-patch" >expect-cr-patch &&
As we are not interested in a lone CR in the middle of the line, I
wonder if we want to anchor the double per-cent to the end of the
line, i.e. "s/%%$/$(printf \\015)/".
On the other hand, we may want to make sure that the new option does
not disturb CR in the middle of the line, so we may be better off
leaving double per-cent unanchored, but allow replacing more than
once on a line, i.e. "s/%%/$(printf \\015)/g".
If we were to go to the latter route, we'd want to try a file with a
CR in the middle of the line (without a CR at the end of any line)
and make sure we won't warn or strip.