v4 regression? Getting "no database name" with MySQL 8

[fsouza]

Describe the Bug

Whenever trying to use v4 and MySQL 8, I get the "error: no database name". The error doesn't happen if I use the binary obtained by running go get -tags mysql github.com/golang-migrate/migrate/cmd/migrate or if I downgrade to MySQL 5.

Steps to Reproduce

Programmatically:

$ mkdir /tmp/debug
$ cd /tmp/debug
$ go mod init github.com/fsouza/debug
$ cat > debug.go
package main

import (
	"os"

	"github.com/golang-migrate/migrate/v4"
	_ "github.com/golang-migrate/migrate/v4/database/mysql"
	_ "github.com/golang-migrate/migrate/v4/source/file"
)

func main() {
	const connString = "mysql://root:@tcp(127.0.0.1:3306)/whatever"

	_, err := migrate.New("file://"+os.Args[1], connString)
	if err != nil {
		panic(err)
	}
}
^-D
$ go build
$ ./debug <path to migrations>
panic: no database name

goroutine 1 [running]:
main.main()
	/tmp/debug/debug.go:16 +0xc4

Expected Behavior

Migrations should run.

Migrate Version

$ cat go.mod
module github.com/fsouza/debug

go 1.12

require github.com/golang-migrate/migrate/v4 v4.1.0

Loaded Source Drivers

file (see debug.go above)

Loaded Database Drivers

mysql (see debug.go above)

Go Version

$ go version
go version devel +99e4ddd053 Tue Dec 18 00:13:58 2018 +0000 darwin/amd64

No difference with Go 1.11.4.

[dhui]

My guess is that there's an issue w/ your DSN. e.g. use root@ instead if root:@.

Have you tried connecting using the mysql driver directly w/o migrate?

[fsouza]

@dhui go-sql-driver works fine with that :, but I removed it just in case and the behavior is still the same (also, migrate splits and reconstructs the DSN). Authentication is fine, migrate fails when it tries to run the command SELECT DATABASE().

But yeah, I dug a little bit and it is a bug with go-sql-driver. Good news is that the bug is already fixed on v1.4.1, so here's a PR: #141

[dhui]

@fsouza Thanks for investigating and opening a PR to fix!