[gentoo-dev] Re: to patch or sed was -> repoman and checking for correct quoting

[Steve Long]

William L. Thomson Jr. wrote:
> On Sat, 2007-11-10 at 18:36 +0100, Bo Ørsted Andresen wrote:
>> On Sat, Nov 10, 2007 at 11:51:37AM +0100, Krzysiek Pawlik wrote:
>> > It's purpose is to remove the ${D} from makefile, additionally ${D} is
>> > in single quotes, so it will not be expanded - is it a bug in repoman
>> > check?
>>
>> What ${D} ? I see none in that makefile. Which is why I think a patch
>> would be better in this case. A patch would actually tell you when half
>> of the substitutions don't match anything... I think this is a point
>> worth making even if it doesn't change your point.
>
> I have kinda gone back and forth between patches and sed. While I agree
> patches are better since they fail to apply at times. Sed stuff can be
> more portable amongst revisions, as I have found with maintaining assp.
> Where the patch grew to the point it had to be mirrored :(.
>
> Now I know some will scream, puke, throw up in their mouth, and so on.
> But seems like sed should have an OPTIONAL argument or etc to tell sed
> to either fail if it can't make the change anywhere. And/or keep/output
> a count of how many things were modified.
>
ed does this by default (which can make it trickier) -- if a standard search
and replace doesn't match, it's considered an error. I appreciate ed isn't
currently part of system set, but imo it should be, since it's specified in
posix. A workaround is grep -q, eg:

if grep -qF '${D}' file; then
        sed -i '#\${D}##' file
fi

(You need to escape $ in a regex or it'll be treated as end marker.) This is
more useful in cases where you need to know what is in the file for
whatever reason (eg grep -q '^FEATURES="[^"]*-blah' /etc/make.conf [1]),
since the sed will not affect the file if there is no match.

Of course, repoman still needs to ignore stuff in single quotes.

[1] if ! grep -qF sandbox < <(portageq envvar FEATURES); then .. (for
example) is safer for general case.


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