Panic in GeometryType.SQL when trying to cast GeometryType to string

[fulghum]

When running in sql-server mode selecting geometry types can cause a panic and crash the server:

2022-06-17T17:10:04-07:00 TRACE [conn 10] committing transaction DoltTransaction {connectTime=2022-06-17T17:09:52-07:00, connectionDb=db2, query=select * from t1}
panic: interface conversion: interface {} is sql.Point, not string

goroutine 2277 [running]:
github.com/dolthub/go-mysql-server/sql.GeometryType.SQL({0x912c58?, 0x40?}, {0x0, 0x0, 0x0}, {0x104012220?, 0x14000dc8018?})
        /Users/jason/Projects/go-mysql-server/sql/geometry.go:293 +0x170
github.com/dolthub/go-mysql-server/server.rowToSQL({0x14000c51bb0, 0x2, 0x14000b1c508?}, {0x14000c3c0c0, 0x2, 0x10253d201?})
        /Users/jason/Projects/go-mysql-server/server/handler.go:720 +0x12c
github.com/dolthub/go-mysql-server/server.(*Handler).doQuery.func4()
        /Users/jason/Projects/go-mysql-server/server/handler.go:500 +0x4fc
golang.org/x/sync/errgroup.(*Group).Go.func1()
        /Users/jason/go/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:57 +0x64
created by golang.org/x/sync/errgroup.(*Group).Go
        /Users/jason/go/pkg/mod/golang.org/x/sync@v0.0.0-20210220032951-036812b2e83c/errgroup/errgroup.go:54 +0x90

When running in a local sql shell, we just see garbled output:

select * from t1;
+---+-----+
| i | g                         |
+---+-----+
| 0 | �?@ |
+---+-----+

The problem is that GeometryType::SQL attempts to cast a geometry type to a string:
https://github.com/dolthub/go-mysql-server/blob/main/sql/geometry.go#L293

We should follow MySQL and convert geometry binary values to hex for display:

mysql> select * from t1;
+------------------------------------------------------+
| g                                                    |
+------------------------------------------------------+
| 0x000000000101000000000000000000F03F0000000000000040 |
+------------------------------------------------------+
1 row in set (0.00 sec)

[jycor]

On my windows machine, MySQL does not convert geometry binary values to hex for display.

[fulghum]

Thanks for testing on Windows. What's the result you see in the mysql shell on Windows for a select of a geometry column with a simple geo type like point(1,2)? Just a couple of garbled characters?

[jycor]

Yep, selecting a simple point like that is mostly null characters

mysql> select point(1,2);
+---------------------------+
| point(1,2)                |
+---------------------------+
|     ��         ?       @ |
+---------------------------+

[fulghum]

Weird that the Windows MySQL shell behavior is different. It seems like a bug to ever print out unreadable chars. Could you search/open a bug report with MySQL and we'll see what they say? I couldn't find any documentation for that behavior anywhere yet. Here's the Mac MySQL shell behavior, for completeness, too:

mysql> select version();
+-----------+
| version() |
+-----------+
| 8.0.29    |
+-----------+
1 row in set (0.00 sec)

mysql> select point(1, 2);
+------------------------------------------------------+
| point(1, 2)                                          |
+------------------------------------------------------+
| 0x000000000101000000000000000000F03F0000000000000040 |
+------------------------------------------------------+
1 row in set (0.00 sec)

Thanks for jumping on the fix, too!

[zachmu]

This appears to be a printing issue from certain shells.

% mysql --version
mysql  Ver 8.0.27-cluster for Linux on x86_64 (MySQL Cluster Community Server - GPL)

mysql> select point(1,2)
    -> ;
+------------------------------------------------------+
| point(1,2)                                           |
+------------------------------------------------------+
| 0x000000000101000000000000000000F03F0000000000000040 |
+------------------------------------------------------+

We need 2 things here:

1. Geometry types on the wire must match what MySQL does
2. Dolt shell should print something reasonable for these values