From a055766e0ca9d2b4a5007f00b007b087e06bc7a5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20H=C3=B6gberg?= Date: Wed, 26 Jun 2019 09:26:41 +0200 Subject: erts: Fix integer overflow in list subtraction CMP_TERM returned an `Sint`, which overflowed the `int` used in erl_rbtree for storing the comparison, causing list subtraction to behave strangely. --- lib/stdlib/test/lists_SUITE.erl | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'lib/stdlib') diff --git a/lib/stdlib/test/lists_SUITE.erl b/lib/stdlib/test/lists_SUITE.erl index 984b51e7ae..9a0fe4b5ca 100644 --- a/lib/stdlib/test/lists_SUITE.erl +++ b/lib/stdlib/test/lists_SUITE.erl @@ -2586,6 +2586,15 @@ subtract(Config) when is_list(Config) -> [1,2,3,4,5,6,7,8,9,9999,10000,20,21,22] = sub(lists:seq(1, 10000)++[20,21,22], lists:seq(10, 9998)), + %% ERL-986; an integer overflow relating to term comparison + %% caused subtraction to be inconsistent. + Ids = [2985095936,47540628,135460048,1266126295,240535295, + 115724671,161800351,4187206564,4178142725,234897063, + 14773162,6662515191,133150693,378034895,1874402262, + 3507611978,22850922,415521280,253360400,71683243], + + [] = id(Ids) -- id(Ids), + %% Floats/integers. [42.0,42.0] = sub([42.0,42,42.0], [42,42,42]), [1,2,3,4,43.0] = sub([1,2,3,4,5,42.0,43.0], [42.0,5]), @@ -2613,6 +2622,8 @@ subtract(Config) when is_list(Config) -> ok. +id(I) -> I. + sub_non_matching(A, B) -> A = sub(A, B). -- cgit v1.2.3