From 5ba6395378e6e92266bba0dd46e3cf3ab6e2fce8 Mon Sep 17 00:00:00 2001
From: Gleb Peregud <gleber.p@gmail.com>
Date: Wed, 2 May 2018 22:07:23 +0200
Subject: [PATCH] docs: mention source of env variables used by
`impureEnvVars`.
---
doc/manual/expressions/advanced-attributes.xml | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/doc/manual/expressions/advanced-attributes.xml b/doc/manual/expressions/advanced-attributes.xml
index f3cf98371..dfd013b5c 100644
--- a/doc/manual/expressions/advanced-attributes.xml
+++ b/doc/manual/expressions/advanced-attributes.xml
@@ -112,7 +112,13 @@ impureEnvVars = [ "http_proxy" "https_proxy" <replaceable>...</replaceable> ];
linkend="fixed-output-drvs">fixed-output derivations</link>, where
impurities such as these are okay since (the hash of) the output
is known in advance. It is ignored for all other
- derivations.</para></listitem>
+ derivations.</para>
+
+ <warning><para><varname>impureEnvVars</varname> implementation takes
+ environment variables from the current builder process. When a daemon is
+ building its environmental variables are used. Without the daemon, the
+ environmental variables come from the environment of the
+ <command>nix-build</command>.</para></warning></listitem>
</varlistentry>