Crate Space Pre-RFC

What's the best solution for namespaces in the rust ecosystem? After a quick survey of proposals, the one with the most support from team members (though not necessarily the team itself) is a way to group crates into a top level item.

Motivation

Structured Trust. Crate spaces provide a counter balance to the ease of adding dependencies. While easily creating/adding dependencies is nice, it invites a proliferation of crates and deep dependency trees.

There are a couple of factors at play:

The rust std is small
There is a convention of prefixing extension crates to with the name of the base crate they are for. E.g. json support for serde is serde-json
Large disjointed dependency trees are unwieldy from a maintainer point of view

References

There have been several attempts at this:

And the subject has been broached in major threads about crates.io policies

Major Questions and Concerns

Referring to namespaced crates in code
If we keep the name prefix (very likely?) we'd maybe want (very likely?) a new sigil - would that break macros?
Referring to namespaced crates in Cargo.toml
Referring to namespaced crates in urls (docs, crates.io and lib.rs)
Can they be nested? Can a crate space use another crate space?
Who controls crate membership in a cratespace / how it's created
- When a space is created and owned, and a child made, should it inherit the space owners? Then what if the owner changes?
Does the entire crate space get a version, or do you select the individual versions of the crates
How non-namespaced crates become namespaced without breaking back compat?
Should users just convert crates into crate namespaces and then use features? Could custom cargo metadata be used for display?

Other notes

Technically, package.name and lib.name are actually decoupled but usually the same in practice (CAD97)

Alternatives