#!/bin/sh -eu
# A target built with a default dofile in the same directory must be rebuilt if a more specific dofile appears.

test -e a.b.c && \
 rm -- a.b.c

>all.do cat <<EOF
redo-ifchange a.b.c
EOF

dofiles="default.do default.c.do default.b.c.do a.b.c.do"

for dofile in ${dofiles}; do
 [ -e "${dofile}" ] && \
  rm -- "${dofile}" || :
done

for dofile in ${dofiles}; do
 >"${dofile}" cat <<EOF
printf '${dofile}\n'
EOF

 redo
 <a.b.c read -r text
 if ! [ "${text}" = "${dofile}" ]; then
  >&2 printf 'a.b.c was built with %s, should have been built with %s\n' \
   "${text}" "${dofile}"
  exit 1
 fi
done