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

[Petteri Räty]

Ferris McCormick wrote:
> On Tue, 2009-01-20 at 21:04 +0200, Petteri Räty wrote:
>> 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
>
> Fine with me
>
>> b) this function should be added to eutils
>
> I don't like this one ---
> [[ ${#} != 2 ]] && die "${FUNCNAME} takes two arguments"
> [[ -e ${2} ]] && die "die target exists"
>
> How does the user recover from that?  I would become irate if a build
> died without giving some useful indication the problem.
>

You did not understand the issue if you are fine with a) but then make
this statement. a) would surely be even more confusing to the user.

Regards,
Petteri