[gentoo-dev] Usage of cp -i to prevent overwriting upstream files

[Petteri Räty]

Many times upstream Java projects don't include build.xml files or
proper build systems so we include build.xml files in $FILESDIR. In case
upstream some day adds one we usually use cp -i to detect if upstream
adds this file in new versions. If devs do their job properly, this will
never show to users. On #gentoo-dev at least grobian and darkside did
not like this and proposed using test and die instead. If we think that
cp -i is not acceptable, this should be made a function to avoid code
duplication in my opinion. Here's a suggestion:

function cp-no-replace() {
	debug-print-function ${FUNCNAME} $*

	[[ ${#} != 2 ]] && die "${FUNCNAME} takes two arguments"
	[[ -e ${2} ]] && die "die target exists"

	cp "${1}" "${2}" || die "cp failed"
}

So do you think:
a) cp -i is fine
b) this function should be added to eutils
c) keep it restricted to java eclasses
d) something else

Regards,
Petteri