From 95ca8a263007666fb210ed8ff6be6429c78b8bc2 Mon Sep 17 00:00:00 2001
From: Markus Triska <triska@metalevel.at>
Date: Mon, 18 May 2020 09:58:09 +0200
Subject: [PATCH] throw instantiation error if the list of options contains a
 variable (#523)

Many thanks to @notoria for the test case!
---
 src/prolog/lib/crypto.pl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/prolog/lib/crypto.pl b/src/prolog/lib/crypto.pl
index be6b6b31..7a246432 100644
--- a/src/prolog/lib/crypto.pl
+++ b/src/prolog/lib/crypto.pl
@@ -259,6 +259,10 @@ crypto_data_hkdf(Data0, L, Bytes, Options0) :-
         '$crypto_data_hkdf'(Data, SaltBytes, Info, Algorithm, L, Bytes).
 
 option(What, Options, Default) :-
+        (   member(V, Options), var(V) ->
+            instantiation_error(option/3)
+        ;   true
+        ),
         (   member(What, Options) -> true
         ;   What =.. [_,Default]
         ).
-- 
2.54.0