Off-by-one error with supportBigNumbers

[joanniclaborde]

Hello,

I think I found an issue with the supportBigNumbers connection option. Running this quick test:

const mysql = require('mysql2/promise');

async function test() {
  const connection = await mysql.createConnection({uri: 'mysql://...', supportBigNumbers: true});
  const [results] = await connection.query(`
    SELECT
      -9007199254740993 AS 'MIN_SAFE_INTEGER - 2',
      -9007199254740992 AS 'MIN_SAFE_INTEGER - 1',
      -9007199254740991 AS 'MIN_SAFE_INTEGER',
      -9007199254740990 AS 'MIN_SAFE_INTEGER + 1',
      -9007199254740989 AS 'MIN_SAFE_INTEGER + 2',
       9007199254740989 AS 'MAX_SAFE_INTEGER - 2',
       9007199254740990 AS 'MAX_SAFE_INTEGER - 1',
       9007199254740991 AS 'MAX_SAFE_INTEGER',
       9007199254740992 AS 'MAX_SAFE_INTEGER + 1',
       9007199254740993 AS 'MAX_SAFE_INTEGER + 2'
  `);
  console.log(results[0]);
  connection.end();
}

test();

Results in the following:

{
  'MIN_SAFE_INTEGER - 2': '-9007199254740993',
  'MIN_SAFE_INTEGER - 1':  -9007199254740992, // Expecting this to be a string
  'MIN_SAFE_INTEGER':      -9007199254740991,
  'MIN_SAFE_INTEGER + 1':  -9007199254740990,
  'MIN_SAFE_INTEGER + 2':  -9007199254740989,
  'MAX_SAFE_INTEGER - 2':   9007199254740989,
  'MAX_SAFE_INTEGER - 1':   9007199254740990,
  'MAX_SAFE_INTEGER':       9007199254740991,
  'MAX_SAFE_INTEGER + 1':   9007199254740992, // Expecting this to be a string
  'MAX_SAFE_INTEGER + 2':  '9007199254740993'
}

Given the values of Number.MIN_SAFE_INTEGER and Number.MAX_SAFE_INTEGER, shouldn't the values highlighted above be strings?

Thanks!

[joanniclaborde]

Here is another test:

SELECT
  9007199254740991, # Number.MAX_SAFE_INTEGER
  9007199254740992,
  9007199254740993,
  9007199254740994,
  9007199254740995,
  9007199254740996,
  9007199254740997,
  9007199254740998,
  9007199254740999,
  9007199254740100,
  9007199254740101

{
  '9007199254740991': 9007199254740991,
  '9007199254740992': 9007199254740992,
  '9007199254740993': '9007199254740993',
  '9007199254740994': 9007199254740994,
  '9007199254740995': '9007199254740995',
  '9007199254740996': 9007199254740996,
  '9007199254740997': '9007199254740997',
  '9007199254740998': 9007199254740998,
  '9007199254740999': '9007199254740999',
  '9007199254740100': 9007199254740100,
  '9007199254740101': 9007199254740101
}

And while I'm at it, I tested the upper limit of UNSIGNED BIGINT. The result is correct (all strings), unless I add the decimalNumbers option:

const connection = await mysql.createConnection({uri: '...', supportBigNumbers: true, decimalNumbers: true});
const results = (await connection.query(`
  SELECT
    18446744073709551615, # UNSIGNED BIGINT
    18446744073709551616,
    18446744073709551617,
    18446744073709551618,
    18446744073709551619,
    18446744073709551620,
    18446744073709551621,
    18446744073709551622,
    18446744073709551623,
    18446744073709551624,
    18446744073709551625
`))[0];
console.log(results[0]);

{
  '18446744073709551615': '18446744073709551615',
  '18446744073709551616': 18446744073709552000,
  '18446744073709551617': 18446744073709552000,
  '18446744073709551618': 18446744073709552000,
  '18446744073709551619': 18446744073709552000,
  '18446744073709551620': 18446744073709552000,
  '18446744073709551621': 18446744073709552000,
  '18446744073709551622': 18446744073709552000,
  '18446744073709551623': 18446744073709552000,
  '18446744073709551624': 18446744073709552000,
  '18446744073709551625': 18446744073709552000
}