Gentoo Archives: gentoo-dev

From: Zac Medico <zmedico@g.o>
To: Gentoo Dev <gentoo-dev@l.g.o>
Subject: [gentoo-dev] [RFC] PROPERTIES=virtual for meta-packages (clarification of definition)
Date: Sun, 24 Aug 2008 21:01:59
2 Hash: SHA1
4 Hi everyone,
6 Since there were some questions about ambiguity in the meaning of
7 the proposed PROPERTIES=virtual [1] value, we need to clarify it.
8 Just as the "live" property [2] is intended to have a pure and
9 simple meaning, so is the "virtual" property. The "virtual" property
10 will serve only as a hint, to indicate that dependency calculations
11 should consider the package to have zero installation cost (see bug
12 141118 [3] for an example of why this knowledge is useful). The
13 "virtual" property should not imply anything more than this, and
14 therefore the package manager should assume that the package is to
15 be treated exactly the same as other ebuilds in every other way. The
16 package should be installed and uninstalled just like any other
17 ebuild, including execution of all of the normal ebuild phase
18 functions that would be executed for any other ebuild that does not
19 exhibit the "virtual" property.
21 Ebuilds that exhibit the "virtual" property commonly serve as a
22 layer of indirection in dependencies. All of the ebuilds in the
23 existing "virtual" category [4] should be eligible to define
24 PROPERTIES=virtual. If the ebuilds in the virtual category were the
25 only ones that exhibited this "virtual" property, then the
26 information that PROPERTIES=virtual represents could simply be
27 inferred from membership of that category. However, existence of
28 meta-packages in the "java-virtuals" category [5], among others,
29 makes it useful to introduce the "virtual" property as a means to
30 identify these ebuilds. Note that some packages, such as x11-libs/qt
31 [6], exhibit this property for some versions and not others. So, in
32 some cases it may be useful to be able to specify the "virtual"
33 property separately for different ebuild versions.
35 Do the name and definition of this PROPERTIES=virtual value seem
36 good? Would anybody like to discuss any changes to the name,
37 definition, or both?
39 [1]
40 [2]
42 [3]
43 [4]
44 [5]
45 [6]
46 - --
47 Thanks,
48 Zac
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