Bug#977154: cctools: reproducible builds: python files contain different content depending on parallelism

[Vagrant Cascadian]

Source: cctools
Severity: normal
Tags: patch
User: reproducible-builds at lists.alioth.debian.org
Usertags: randomness
X-Debbugs-Cc: reproducible-bugs at lists.alioth.debian.org

Various .py files contain different code dependending on the level of
parallelism of the build.


The attached patch to debian/rules passes --no-parallel to dh, which
results in a reproducible build, but it is unclear weather the resulting
code is "correct", as some files contain additional code compared to
builds done with parallelism.


In general, I've found the parallel builds to produce the same code as
other parallel builds with different levels of parallelism, but clearly
different than serial builds.

Presumably there are jobs when run in parallel complete in a relatively
consistent order (e.g. two jobs, one very fast and one very slow), but
different than when run in serial (e.g. the slow job runs first?). I
have attached diffoscope output from a serial vs. parallel build.


Thanks for maintaining cctools!


live well,
  vagrant
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