Gentoo Archives: gentoo-dev

From: "Michał Górny" <mgorny@g.o>
To: gentoo-dev@l.g.o
Subject: [gentoo-dev] [PATCHES] python-r1, add integrity checks for redefined control vars
Date: Wed, 01 Mar 2017 16:03:15
1 Hi,
3 Here's a patch serie inspired by the recent spidermonkey issue [1]. Long
4 story short, both mozcoreconf-*.eclass and spidermonkey were setting
5 different values of PYTHON_REQ_USE and inherit python-any-r1. Thanks to
6 double include guards, the dependencies were set using the first value
7 on the first iteration. However, python_setup() used the final value,
8 being more strict as a result.
10 This patch series aims to reduce the likeliness of such mistakes,
11 by comparing the values of output variables between successive eclass
12 inherits. This both catches some mistakes of overwriting the value,
13 and any potential integrity issues in eclass itself.
15 The remaining commits are purely cleanup/refactor.
17 However, the following technical limitations need to be noted:
19 1. We can only detect changes of control variables between successive
20 inherits of eclass, which makes every solution highly dependent
21 on the inherit order. If you 'inherit mozcoreconf-v4 python-any-r1',
22 the control variables are overwritten before python-any-r1 can see them.
24 2. There was a suggestion to make the eclass output variables updated
25 for the last values of control. However, the output variables are
26 currently marked readonly, to avoid accidental rewrites. If we were
27 to update them, we would have to disable that.
29 3. The same bugs (and also the case of defining after inherit) could
30 be caught if control variables were made readonly after setting globals.
31 However, this would cause spurious errors if the ebuild was sourced
32 more than once by the PM.
34 Please review.
36 [1]:
38 --
39 Best regards,
40 Michał Górny