doc: mention how to turn on pure evaluation mode in manual

The flag is `--pure-eval`, which can be found by looking at the test suite; it
should be in the notes describing the feature as well, since otherwise users may
assume this is referencing something like `nix-shell --pure`.
This commit is contained in:
Benjamin Hipple 2020-02-15 01:37:44 -05:00
parent 9af10b753c
commit 762febafe2

View file

@ -503,14 +503,14 @@
</listitem> </listitem>
<listitem> <listitem>
<para><emphasis>Pure evaluation mode</emphasis>. This is a variant <para><emphasis>Pure evaluation mode</emphasis>. With the
of the existing restricted evaluation mode. In pure mode, the Nix <literal>--pure-eval</literal> flag, nix enables a variant of the existing
evaluator forbids access to anything that could cause different restricted evaluation mode that forbids access to anything that could cause
evaluations of the same command line arguments to produce a different evaluations of the same command line arguments to produce a
different result. This includes builtin functions such as different result. This includes builtin functions such as
<function>builtins.getEnv</function>, but more importantly, <function>builtins.getEnv</function>, but more importantly,
<emphasis>all</emphasis> filesystem or network access unless a <emphasis>all</emphasis> filesystem or network access unless a content hash
content hash or commit hash is specified. For example, calls to or commit hash is specified. For example, calls to
<function>builtins.fetchGit</function> are only allowed if a <function>builtins.fetchGit</function> are only allowed if a
<varname>rev</varname> attribute is specified.</para> <varname>rev</varname> attribute is specified.</para>