Fix @ parsing in versions

[elcritch]

Dependency versions would get messed up with @ being added to the pkg name in some cases.

[Araq]

Why the heck would @ be part of a package name?

[elcritch]

Why the heck would @ be part of a package name?

Come to think of it shouldn't. I thought maybe it was from some requires format, but that's not a thing.

Hmmm, I'm digging into where the @ is coming from. Probably an errant usage of the pretty print format for a specific version.

[elcritch]

That makes more sense. An old package of mine had an @ in a requires line in an old release. Probably from copying a nimble install pkg@#head or futzing with Nimble.

Now the addRelease logic can handle bad Nimble releases by skipping them. Surprising we haven't needed that yet.

[Araq]

1. It's weirdly specific. There are other invalid chars, I'm sure.
2. I think an Option would work better here rather than an exception, but I don't know for sure.

[elcritch]

1. It's weirdly specific. There are other invalid chars, I'm sure.

True, it is. Perhaps it should check for any non-ascii char that's not in the version char set? Not sure it's official, but Nimble packages seem to be ascii limited, or perhaps should?

2. I think an Option would work better here rather than an exception, but I don't know for sure.

I thought about that, but it'd be a pain. It'd have to go through the Nimble parser and just end up with the same result of skipping that Nimble release.

[Araq]

Use strutils.PunctuationChars except the chars we need, >= etc, depending on the logic.

[elcritch]

Use strutils.PunctuationChars except the chars we need, >= etc, depending on the logic.

Unfortunately that doesn't work since we can have URLs in the name component.

Still I tried to generalize it a bit more using validIdentifier or checking for a URL. If the url ends with @ it's also an error. There's cases IIRC where @ can be used in a URL itself.

Version strings are checked for incomplete parsing ignoring dangling whitespace.

Also I discovered I'm not the only one who's gone from nimble install xyx@#branch to requires "xyx@#branch" by accident.