depgraph: make _minimize_children deterministic (bug 631894) #209
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mrueg
reviewed
Sep 24, 2017
| # packages first, in case rebuilds are needed, and also sort | ||
| # in ascending order so that older versions are eliminated | ||
| # first. | ||
| pkgs = (sorted(pkg for pkg in pkgs if pkg.installed) + |
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How big is the list going to be? Maybe it makes sense to bisect.insort here and not touch every element twice.
installed = []
not_installed = []
for pkg in pkgs:
if pkg.installed:
bisect.insort(installed, pkg)
else:
bisect.insort(not_installed,pkg)
pkgs = installed + not_installed
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Typically we're only dealing with 2 packages, so there's not much cost here to optimize away. Also, insort would be less efficient than something like this:
installed = []
not_installed = []
for pkg in sorted(pkgs):
if pkg.installed:
installed.append(pkg)
else:
not_installed.append(pkg)And that's going to have a negligible performance difference compared to my 2-line version that's easier to read.
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okay, if it's just a small list then nevermind my comment 👍
mrueg
approved these changes
Sep 24, 2017
In order for the eliminate_pkg loop to produce deterministic results, the order of the pkgs list must not be random. Prefer to eliminate installed packages first, in case rebuilds are needed, and also sort in ascending order so that older versions are eliminated first. X-Gentoo-bug: 631894 X-Gentoo-bug-url: https://bugs.gentoo.org/631894 Reviewed-by: Manuel Rüger <mrueg@gentoo.org>
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In order for the eliminate_pkg loop to produce deterministic results,
the order of the pkgs list must not be random. Prefer to eliminate
installed packages first, in case rebuilds are needed, and also sort
in ascending order so that older versions are eliminated first.
X-Gentoo-bug: 631894
X-Gentoo-bug-url: https://bugs.gentoo.org/631894
@danielrobbins