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We switched from Lua 5.2 to Lua 5.3 and suddenly a seemingly small change in Lua's number formatting is hitting us really hard:

Before 5.2, a number value of 41.0 would produce a string of '41'.  After 5.3, it produces '41.0':

Lua 5.2.3  Copyright (C) 1994-2013 Lua.org, PUC-Rio
> a = 41.0
> print(a)
41

Lua 5.3.2  Copyright (C) 1994-2015 Lua.org, PUC-Rio
> a = 41.0
> print(a)
41.0

This little detail becomes "great" fun when you use numbers as integers in SQL statement:

local id = tonumber(query.id)  -- Get the id from a string in a webform
local res = db:execParams('select * from foo where id = $1::integer', id)

In PostgreSQL this results in an error like "Invalid input syntax for type integer: 41.0".

I will find a way to deal with this (probably in the luapgsql interface), for now I just wanted to share the fun ;)