From 0ec372eb2b213292a610d9b64e8d1d37e9597c9a Mon Sep 17 00:00:00 2001 From: Randy Palamar Date: Sun, 27 Aug 2023 09:01:01 -0600 Subject: [PATCH] vis-lua.c: silence warning about implicit conversion `SIZE_MAX` cannot be represented accurately in `lua_Number`. A correct solution probably doesn't exist but we can silence the warning by explicitly casting to `lua_Number` and changing the comparison to `<` instead of `<=`. checkpos() deals with large numbers for file ranges. For most users we can assume no one is editing files that are `SIZE_MAX` bytes long (many petabytes). For obscure systems where `SIZE_MAX` is a small number this will result in a maximum range (in lua) of 1 byte less than before. fixes #1120: vis-lua.c:504:21: warning: implicit conversion changes value --- vis-lua.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/vis-lua.c b/vis-lua.c index acc48d2d1..bee077cc6 100644 --- a/vis-lua.c +++ b/vis-lua.c @@ -501,7 +501,11 @@ static size_t getpos(lua_State *L, int narg) { static size_t checkpos(lua_State *L, int narg) { lua_Number n = luaL_checknumber(L, narg); - if (n >= 0 && n <= SIZE_MAX && n == (size_t)n) + /* on most systems SIZE_MAX can't be represented in lua_Number. + * using < avoids undefined behaviour when n == SIZE_MAX+1 + * which can be represented in lua_Number + */ + if (n >= 0 && n < (lua_Number)SIZE_MAX && n == (size_t)n) return n; return luaL_argerror(L, narg, "expected position, got number"); }