From 61a6d1aae2f20ca7e714480907d87c6419ef1e80 Mon Sep 17 00:00:00 2001 From: Ryan Burns Date: Tue, 15 Dec 2020 00:05:57 -0800 Subject: [PATCH] stdenv: trim random seed to avoid reference cycles Using the full store hash as the random seed occasionally caused reference cycles when the invocation was stored in output artifacts. For example, cross-compiled gcc was failing due to this: https://hydra.nixos.org/eval/1631713#tabs-now-fail Simply truncating the hash is sufficient to avoid this. --- pkgs/build-support/setup-hooks/reproducible-builds.sh | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/pkgs/build-support/setup-hooks/reproducible-builds.sh b/pkgs/build-support/setup-hooks/reproducible-builds.sh index 2d8db6ff7d3c..5b01c213fe4a 100644 --- a/pkgs/build-support/setup-hooks/reproducible-builds.sh +++ b/pkgs/build-support/setup-hooks/reproducible-builds.sh @@ -1,4 +1,9 @@ # Use the last part of the out path as hash input for the build. # This should ensure that it is deterministic across rebuilds of the same # derivation and not easily collide with other builds. -export NIX_CFLAGS_COMPILE+=" -frandom-seed=${out##*/}" +# We also truncate the hash so that it cannot cause reference cycles. +export NIX_CFLAGS_COMPILE+=" -frandom-seed=$( + outbase="${out##*/}" + randomseed="${outbase:0:10}" + echo $randomseed +)"