jbhoot / poc-buggy-geographic-point-parsing-by-node-mysql2

A small demo to demonstrate a *possible* bug in node-mysql2 while accessing geographic data (SRID 4326) from mysql8

Problem

node-mysql2 seems to swap x and y values of a geographic Point stored in mysql8 when it is retrieved through node-mysql2 without special parsing.

This repository tries to demonstrate the bug.

How to reproduce

1. Ensure that a MySQL8 instance is running.
2. Clone the above mentioned repository.
3. Switch to branch feat/demo.
4. Ensure that a schema as described in db.sql exists.
5. Set up a .env file according to the .env.template.
6. npm ci
7. Run the index.js script MYSQL_VERSION=8 node index.js.

The last step above – script execution – should produce the following output:

$ MYSQL_VERSION=8 node index.js
Testing with MySQL v8...

AS INTERPRETED BY MYSQL8's ST_X, ST_Y functions:
┌─────────┬─────────────┬────────────────────┬──────────────┐
│ (index) │  st_x(pos)  │     st_y(pos)      │ st_srid(pos) │
├─────────┼─────────────┼────────────────────┼──────────────┤
│    0    │ -33.3109317 │ 117.34617329999999 │     4326     │
│    1    │ -35.3109317 │    101.3461733     │      0       │
└─────────┴─────────────┴────────────────────┴──────────────┘

AS INTERPRETED BY node-mysql2:
┌─────────┬─────────────┬─────────────┐
│ (index) │      x      │      y      │
├─────────┼─────────────┼─────────────┤
│    0    │ 117.3461733 │ -33.3109317 │
│    1    │ -35.3109317 │ 101.3461733 │
└─────────┴─────────────┴─────────────┘

Expected result

For all the rows:

• x column in the second table should show the value in st_x column of first table.
• y column in the second table should show the value in st_y column of first table.

To demonstrate the same from MySQL CLI Shell:

mysql> select st_astext(pos), st_x(pos), st_latitude(pos) from testpoint where st_srid(pos) = 4326;

+--------------------------------+-------------+------------------+
| st_astext(pos)                 | st_x(pos)   | st_latitude(pos) |
+--------------------------------+-------------+------------------+
| POINT(-33.3109317 117.3461733) | -33.3109317 |      -33.3109317 |
+--------------------------------+-------------+------------------+
1 row in set (0.00 sec)

In the above query result, st_x() and st_latitude() point to the first value in the Point, which is in accordance with how SRID 4326 is defined in MySQL.

Actual result

For the first row 0 (containing data for SRID 4326):

• x column in the second table shows the value in st_y column of first table.
• y column in the second table shows the value in st_x column of first table.

In other words, node-msyql2 apparently swaps the values for x and y in a retrieved geographic point.

AS INTERPRETED BY MYSQL8's ST_X, ST_Y functions:
┌─────────┬─────────────┬────────────────────┬──────────────┐
│ (index) │  st_x(pos)  │     st_y(pos)      │ st_srid(pos) │
├─────────┼─────────────┼────────────────────┼──────────────┤
│    0    │ -33.3109317 │ 117.34617329999999 │     4326     │ <---- correct: x is lat, y is long
└─────────┴─────────────┴────────────────────┴──────────────┘

AS INTERPRETED BY node-mysql2:
┌─────────┬─────────────┬─────────────┐
│ (index) │      x      │      y      │
├─────────┼─────────────┼─────────────┤
│    0    │ 117.3461733 │ -33.3109317 │ <---- incorrect: x is long, y is lat
└─────────┴─────────────┴─────────────┘

Relevant observations

node-mysql2 behaves as expected, i.e., no swapped x and y, for a point with SRID 0.

node-mysql2 also behaves correctly for both SRIDs in mysql5 (probably because mysql5 ignores SRID anyway).