Gentoo Archives: gentoo-dev

From: "Michał Górny" <mgorny@g.o>
To: gentoo-dev@l.g.o
Cc: multilib@g.o
Subject: [gentoo-dev] [PATCH 0/3] Remove parallel run support from multilib & multibuild
Date: Thu, 11 Dec 2014 10:36:47
Message-Id: 1418294192-9639-1-git-send-email-mgorny@gentoo.org
1 Hello, everyone.
2
3 Following a similar change in distutils-r1, I would like to remove
4 the parallel run support in multilib eclasses, and effectively from
5 multibuild completely.
6
7 The goal is to make things simpler, and follow PMS properly. Right now
8 the parallel runs imply running commands in a subshell. This has three
9 important implications:
10
11 1. variable exports and environment changes inside the implicit subshell
12 don't affect the outer scope -- developers are sometimes confused by
13 that,
14
15 2. parallel runs can collide if temporary files aren't named uniquely --
16 think of ffmpeg, waf,
17
18 3. 'die' called in a subshell is unsupported by the PMS, and didn't make
19 it into EAPI 6.
20
21 The side advantages are that we can get rid of multiprocessing inherit
22 and locking in multibuild_merge_root().
23
24 Possible issues: if people were relying on commands inside parallel not
25 to affect the outer environment (i.e. doing 'cd' and expecting the next
26 call to start in the initial location, or exporting variables and
27 expecting them to disappear), the ebuilds will fail randomly. However,
28 that's quite unlikely.
29
30 Your thoughts?
31
32 --
33 Best regards,
34 Michał Górny

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