• Do only one thing
• Non breaking API changes
• Tested

What did this pull request do?

When calling gorm.Open, there is the following code:

if config.Dialector != nil {
	err = config.Dialector.Initialize(db)
}

config.Dialector.Initialize(db) typically calls sql.OpenDB to create an *sql.DB, and starts an goroutine db.connectionOpener(ctx).

Next, a typical database driver will attempt to connect to the schema specified in the DSN. If an error occurs at this time (such as the specified schema not existing), it will cause config.Dialector.Initialize(db) to return an error. However, after receiving this error, GORM does not attempt to close *sql.DB. This causes the db.connectionOpener(ctx) goroutine to leak.

In my scenario, I used the wrong schema and retried calling gorm.Open multiple times. By observing the dumped goroutine, I found that there were a large number of db.connectionOpener(ctx) goroutines. After applying this code fix, these goroutines are no longer leaked.

This pull request try to close the *sql.DB variable if possible.

User Case Description

Same as above.