fix: error opening file when window.width is not lua number

[williamhCode]

fixes #789. One comment is that if the width is invalid, normally neo-tree still works and doesn't throw an error. However, since I added this fix, errors only appear if you happen to open a file when there's no other windows (which only happens rarely). This is a bit inconsistent and might confuse users, should we bother at all?

[cseickel]

errors only appear if you happen to open a file when there's no other windows (which only happens rarely). This is a bit inconsistent and might confuse users, should we bother at all?

I would say that in this context, we should just set width to the default value of 40 and not throw any errors. If we are going to validate the value, it should really be done in the setup method.

[williamhCode]

I updated the commit so it matches nui's size handling more and sets the default value of 40. There's still things that don't quite match, such as if the width is very small and if the width is invalid. Because of this, I'm thinking maybe instead of doing a vsplit, we could just switch the current window to the file, then toggle the tree. Then, we don't have to try to match the width handling to nui.

[cseickel]

we could just switch the current window to the file, then toggle the tree. Then, we don't have to try to match the width handling to nui.

That won't work. A lot of people get really finicky about seeing the window open and close. There's also the issue of the built-in window stealing prevention and having to keep the cursor and scroll in the same positions.

I think what you have here is good.