Date: Thu, 8 Apr 2021 00:50:06 +0200
From: Wolf <wolf@wolfsden.cz>
To: ~alpine/devel@lists.alpinelinux.org
Subject: Why does apk fail to install packages with 0 size?
Message-ID: <20210407225006.thogaepvkqq2ytbx@wolfsden.cz>
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Hello,

To follow up on my original mail thread (apk not installing a file),
I've dived into apk's source code and managed to track the problem to:

src/database.c:
2920
2921         if (newpkg->installed_size !=3D 0) {
2922                 r =3D apk_db_unpack_pkg(db, ipkg, (oldpkg !=3D NULL),
2923                                       cb, cb_ctx, script_args);

Which I guess means that if installed size of the new package is zero, the
unpacking is skipped. That might sound reasonable, but leads to packages wi=
th
package function looking like:

package() {
        mkdir -p -- "$pkgdir"
        touch -- "$pkgdir/test-foo"
}

To be silently skipped with no errors nor warnings. That is highly confusin=
g,
because there is not reason this should not work. For the time being, my
workaround is:

package() {
        mkdir -p -- "$pkgdir"
        echo >"$pkgdir/test-foo"
}

Which is bit sad result given how much time I've spent on this. :/

So, my question is: Is this behaviour intentional? If so, why? And if it
is not, what would be nice way to fix this? I can work on patch, however
I'm not sure what would be the best angle.

W.

--=20
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.

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