Gentoo Archives: gentoo-dev

From: Marius Mauch <genone@g.o>
To: gentoo-dev@l.g.o
Subject: [gentoo-dev] RFC: Should preserve-libs be enabled by default?
Date: Wed, 28 May 2008 23:17:55
1 As portage-2.2 is about to be unmasked into ~arch soon (there is one
2 weird bug to solve before) it's time to ask for some input on one of
3 the important new features, FEATURES=preserve-libs.
5 (if you're already familiar with it you can skip this paragraph)
6 Simply said, when this feature is enabled portage keeps track of all
7 installed libraries and binaries linked against them, and if a package
8 upgrade would remove a library that's still in use portage will keep
9 the library around, owned by the new version and also registered in a
10 separate file. There is also an internal package set that can be used
11 to rebuild all packages linked against libraries preserved in this way,
12 and the user is notified after each emerge operation that he should do
13 that (the example is from an expat downgrade in case you wonder about
14 the versions):
15 !!! existing preserved libs:
16 >>> package: dev-libs/expat-1.95.8
17 * - /usr/lib64/
18 * - /usr/lib64/
19 Use emerge @preserved-rebuild to rebuild packages using these libraries
21 The purpose of this is to keep the system operational after library
22 upgrades until all affected packages could be rebuilt and to simplify
23 the process, not to avoid the rebuilds.
25 Now the question is if this behavior should be enabled by default?
27 In the existing prereleases it has been enabled to get some real-world
28 testing, and it's been quite effective, though there are still a few
29 issues to be worked out (e.g. if libraries are moved between packages).
30 And no doubt a few more bugs will turn up over time.
31 Also it is not going to be a perfect solution against all runtime link
32 errors, but if enabled it should eliminate the need for revdep-rebuild
33 in most cases.
34 One concern raised by some people is that it might cause old libraries
35 with security issues to stay on the system for eternity even though
36 the package was upgraded, and eventually be preferred by new builds.
37 I can't rule this out completely but thinks it's very unlikely, as
38 preserved libraries are specially tracked and the user is notified
39 about their existance after every emerge operation (similar to glep42
40 news). And new builds shouldn't find them as the unversioned .so
41 symlinks ar going to point to the current versions.
42 So personally I'm not too worried about this concern becoming reality,
43 but I can understand if others are.
45 So, do you think it should be enabled by default?
47 Marius
49 PS: Obviously, if you haven't tested portage-2.2 yet, now would be a
50 good time.
52 --
53 Public Key at
55 In the beginning, there was nothing. And God said, 'Let there be
56 Light.' And there was still nothing, but you could see a bit better.


File name MIME type
signature.asc application/pgp-signature


Subject Author
[gentoo-dev] Re: RFC: Should preserve-libs be enabled by default? Ryan Hill <dirtyepic@g.o>
Re: [gentoo-dev] RFC: Should preserve-libs be enabled by default? Donnie Berkholz <dberkholz@g.o>
Re: [gentoo-dev] RFC: Should preserve-libs be enabled by default? "Rémi Cardona" <remi@g.o>
Re: [gentoo-dev] RFC: Should preserve-libs be enabled by default? Mike Auty <ikelos@g.o>
[gentoo-dev] Re: RFC: Should preserve-libs be enabled by default? (Diego 'Flameeyes' =?utf-8?Q?Petten=C3=B2?=)
Re: [gentoo-dev] RFC: Should preserve-libs be enabled by default? Arfrever Frehtes Taifersar Arahesis <arfrever.fta@×××××.com>