Re: lexical parse of hex literal fails to handle overflow: lua 5.3 and 5.4-alpha

[Payo Nel <payonel@...>]

the parser also incorrectly "upgrades" a valid integer to a float value with a minimum integer value:

tonumber is correct here:

> tonumber('-9223372036854775808',10)

-9223372036854775808

lexical parse is not

> -9223372036854775808

-9.2233720368548e+18

> math.mininteger

-9223372036854775808

> math.type(-9223372036854775808)

float

> math.type(math.mininteger)

integer

---

From: Payo Nel
Sent: Thursday, March 26, 2020 5:36 PM
To: lua-l@lists.lua.org <lua-l@lists.lua.org>
Subject: lexical parse of hex literal fails to handle overflow: lua 5.3 and 5.4-alpha

 

the lexical parser continues to read hex values, ignoring that the value may be overflowing the maximum integer

e.g. on 64 bit lua (5.3 and 5.4-alpha have the same issue)

> 0x7FFFFFFFFFFFFFFF

9223372036854775807

> 0xFFFFFFFFFFFFFFFF

-1

> 0xFFFFFFFFFFFFFFFFF

-1

> 0x10000000000000000

0

> 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

-1

expected:

the l_str2int should fail and the lexical parser should fall back to floats