export the database/sql driver implementation type

[NyaaaWhatsUpDoc]

This allows for further user customization of the database/sql sqlite driver, for example in GoToSocial where we would require translating any returned errors. This does so while not breaking the current API.

[ncruces]

I'm not against this, but it'll take some convincing.
Can you show me how you'd use this, what do you need it for?

The driver was initially a singleton, now it's a global variable. You're assuming it is set on an init?
But what if two client packages need different customizations?

[ncruces]

I think I understand why you might want to export the current singleton: so it can be wrapped.

I can also understand the frustration with me taking over the "sqlite3" driver name. I was always conflicted about it, but decided it was the least bad option (and still added an escape hatch).

I don't understand why the driver would need to stop being a singleton and become a global variable.

[NyaaaWhatsUpDoc]

Okay so thoughts for designing it were as follows:

• exporting the driver type, so as you say, it can be wrapped. in GoToSocial we do this so we can simply translate all the errors at the lowest level and not have to worry about them by the time they've ended up in our ORM (https://github.com/uptrace/bun)

• making the registered database/sql singleton exported so you can customize it in your own manner and still access it under the registered name "sqlite3, without having to set any linker flags to unset the registration variable name. i was thinking that people not so comfortable with passing linker flags would likely end up opting to register a new instance of the driver under a different name in the sql package, meaning you'd have an unnecessary singleton hanging around. not hugely important but i figured it might be a bit easier this way

i'm not hugely tied to that second point so if you'd prefer i can remove the exported global variable!

[ncruces]

Yes, I would really rather not export the global variable.
But if you have a better idea for driver registration (and me not taking over "sqlite3") I'm all ears.

I can explain why I did it like this (and why I disagree with modernc using "sqlite" instead).
Having multiple SQLite drivers in the same process is not just wasteful but outright dangerous, for reasons I explain here.

So, in a sense, I want to panic if people try to use mattn and my driver in the same process (ideally I'd panic for modernc too).

The counter argument is that all 3 drivers (mattn, modernc, ncruces) have different DSNs, so they should have different registration names.

Ideally, none of the drivers would "auto-register," but that's the Go convention, so that's out.

The only solution I see, is what I did with package embed: a package driver to register, and a package driver/impl (?) that exports the implementation for customization. Would that be better? I can prototype it for you.

Sorry, this is the kind of stuff that I'd really like to get right at once, but that only happens when someone shows up with a weird requirement.

[NyaaaWhatsUpDoc]

Yes, I would really rather not export the global variable. But if you have a better idea for driver registration (and me not taking over "sqlite3") I'm all ears.

I can explain why I did it like this (and why I disagree with modernc using "sqlite" instead). Having multiple SQLite drivers in the same process is not just wasteful but outright dangerous, for reasons I explain here.

So, in a sense, I want to panic if people try to use mattn and my driver in the same process (ideally I'd panic for modernc too).

The counter argument is that all 3 drivers (mattn, modernc, ncruces) have different DSNs, so they should have different registration names.

Ideally, none of the drivers would "auto-register," but that's the Go convention, so that's out.

The only solution I see, is what I did with package embed: a package driver to register, and a package driver/impl (?) that exports the implementation for customization. Would that be better? I can prototype it for you.

Sorry, this is the kind of stuff that I'd really like to get right at once, but that only happens when someone shows up with a weird requirement.

no worries that makes sense! will make the change 👍

[NyaaaWhatsUpDoc]

@ncruces have removed the global variable, and renamed the driver implementation to instead be SQLite{}

[ncruces]

Thanks! I'll fix some doc nits in a followup; hope you don't mind.

[ncruces]

Just a heads up: because I have encryption in the pipeline, it will take me some time to tag a release of this.

I'm planing to make some small backwards incompatible changes to the VFS API in #82, and I really want to get them right. I also want to make sure encryption is works the way it should, as that's a sensitive matter.

If you're not creating a VFS (and I guess no one is, yet), you can use main for a while, then update.
That won't cause any breakages.