Remove version convention / semver prefix from versions.

[anuraaga]

Fixes #802

Changes

Removes the convention of prefixing version numbers with things like semver:, git:. This comes from the idea that the version is the version, adding prefixes makes it something that isn't the version, nor a duck. If a user queries their data for a version number, it is very unintuitive to have to prefix queries with semver:, or otherwise every single data store that stores this data needs to natively understand our spec well enough to do this for them which doesn't seem like a worthwhile restriction.

I didn't add a separate attribute for the version type - in the issue, no one championed for it. I can add it if it seems very useful. Need to do it now instead of later since then it needs to be foo.version.id + foo.version.type, we can't have foo.version + foo.version.type based on our conventions for attribute key namespaces.

[arminru]

Changelog please! SIGs should be advised to remove any existing version prefixes added by their SDK and instrumentations.

[anuraaga]

Oops, thanks!

[MrAlias]

The downside of removing this prefix is there is an inability programmatically interpret this version. Similar to how the OCI realized that the original docker hashing scheme was not adequate to fully describe the image hash by itself (you needed to have prior knowledge of the hashing algorithm and hash size used) they developed a digest concept that is similar.

This approach allowed for the extensibility of the container hash while remaining fully descriptive of the algorithm. I think it points out a valid approach and one that will help the project in the long term if we try to achieve the same goals here with the version.

[Oberon00]

The downside of removing this prefix is there is an inability programmatically interpret this version.

Agreed, but at the same time, the current spec requires instrumentations to know or guess the format of the version. We could add an raw: or ?: prefix for that but I think this may just be a part that is overengineered. And as mentioned in the PR description, we can always add a companion attribute that tells the version format later.

[tigrannajaryan]

Need to do it now instead of later since then it needs to be foo.version.id + foo.version.type, we can't have foo.version + foo.version.type based on our conventions for attribute key namespaces.

We can still add foo.version_type if it turns out that we need it in the future after all. So, it is desirable but not mandatory to make the decision right now. IMO, we don't need the version type.

[bogdandrutu]

I've never seen so many approvers :)