I have one addon that watches for 6 other addons.

I would argue that even in that worst case scenario of someone using it poorly >= 2.5 that they are still better off than someone not checking a version number at all. It eliminates versions < 2.5, assuming those are known to be incompatible (otherwise there was no point in the check). It may be minor, but that's the worst case scenario and there is only benefit there & no loss.

I would also recommend checking first...but if your doing that, then that nullifies the original comment. If that user checked the existence of the function first it really doesn't matter if he uses >= 2.5 and the other addon removes the function. However that wouldn't catch a problem if the users updates the addon & changes the function. I'm just saying, the existence of the function isn't always the problem. I agree that I wouldn't want to bump version numbers either & wouldn't use the check, but that doesn't mean its not beneficial if used. More work to keep it up to date, but it would prevent problems too.

As I said I never had any intention of posting it, because I agree it is a bit superfluous, but someone asked me for it and I still see no harm or downside, so I wasn't going to tell them no.

I just wanted to give you a hint that this might be something not worth maintaining, since both its features are redundant.

Of course. But a library should at the very least reduce code duplication, or simplify working with awkward API, implementation details and such.



Okay, so it reduces some bloat. If you need to check for many addons, that may pay off. With just one, not worth it.


"A good library is easy to use, and hard to misuse." That's what I mean by "encourages bad practice". You provide the tool to check whether version >= 2.5. It's easy to misuse.


If I wanted to call a function from another add-on, I'd first check that it exists, and then pcall(it). Who wants to test against each new version that comes out, and manually bump version numbers?

In my previous post I actually thought the version info was more useful than plain presence check. Now I'm 100% convinced version info is superfluous. LibStub does that. If an add-on has a public, versioned API, it should publish it via LibStub. Why have another dependency doing the exact same thing?

I wrote it strictly for myself & my addons. I use it in several addons and one in particular that has to watch for several other addons for compatability. It was just easier & cleaner imo.

This wasn't written with other developers in mind and I had no intention of posting it. I only posted it because another user found it in one of my addons and requested to use it so I posted it for him.

I'm not disagreeing with the fact that this library doesn't really offer much, but as for the comments

1) The same could be said for any library. If it can be done in a library it could be done in the addon itself.

As for the ON_LOADED, the OptionalDependsOn statement is true...but I don't see why any of it needs to be done in ON_LOADED, just because that's what everyone is used to doing is not a good reason.

• Although your way you can watch ON_LOADED to see when an addon is loaded & you could immediately try to run your compatibility code, I can't think of any reason to need to run it immediately and it doesn't sound like a good idea. When your addon sees the addonName "JunkIt" that is the same time my addon sees "JunkIt" and that is when my addon STARTS to run code & initialize everything. So although you could immediately try to run some compatability code, my addon probably hasn't finished initializing yet so you probably shouldn't be calling another addons code or messing with their controls in ON_LOADED regardless of which method your using IMO.
  
• If you need to run some of your own code, that does not need any access the other addon, then it could be done immediately. But if you don't need any access to the other addon, then why the dependency on it. I admit I'm sure there is an example out there for this, but I can't think of one, so even that seems like a moot point.
  
• If your only watching to see which addons are loaded in ON_LOADED & you are running your compatability code later...then the point seems irrelevant, because both methods require code to be run later (outside of ON_LOADED) and then a dependency is not needed.

2) That comment is based off of the idea that a developer will use it improperly. The same argument could be made that any library used improperly could cause errors.

I'm not saying the version check is an awesome feature or that it would even prove useful to many, but it was an easy additional feature that I thought might prove useful somewhere/sometime, it is optional, & it is harmless. If a developer checks the version number using a inequality like: >= 2.5 rather than a strict equality or based off of a set of version numbers that he knows it will work for....that's his own fault. Not to mention that your alternative has no way of knowing what version is loaded. How is that better? Even if a developer doesn't know any better and unwisely uses >= 2.5, they are still better off than someone using your method whos not checking a version number at all because at least it will exclude versions < 2.5. Your method is guaranteed to run into the problem/error that you mentioned since you can't check version numbers. But, with the version check option they have the ability to catch & prevent errors such as that.

Your example is actually a good example of why the version check could be a good thing. Because if its used properly with a strict equality or the proper inequality (including only versions that are known to be compatible) then when that other addon removes that feature in 3.7 your addon won't have any problems. If a developers complaint is then, but everytime they update their addon I have to update mine to change the dependent version number....then don't use it, its optional. You'll just have to deal with the consequences that when they remove that feature your addon is going to crash, which is no worse off than anyone is now. So I see nothing negative about having a version check.

Sorry for nitpicking, but I think this library is superfluous.

1) Any add-on can check whether another add-on is loaded in their ON_LOADED handler. No need to have a library that does the exact same thing, and query that library. Plus, this extra indirection might conceal the otherwise obvious requirement that you can't make the query inside your ON_LOADED handler unless you have OptionallyDependsOn: in manifest.

2) This library adds version information. That looks nice at first, but encourages bad practice IMO. When you want to cooperate with another add-on, you shouldn't make your decisions around whether its version is >=2.5 or <=4.1. You need a feature/API to be present. That feature might be introduced in 2.5, so you check for version>=2.5, and if the feature is removed in 3.7 you're broken.

Thanks circonian, will implement it into my connected addons so other devs can use it to check stuff (in addition to checking for existing global varibales etc.)