RFC: Remove glob-import functionality completely

[rust-highfive]

Issue by Aatch
Sunday Jan 26, 2014 at 22:47 GMT

For earlier discussion, see rust-lang/rust#11825

This issue was labelled with: B-RFC in the Rust repository

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Glob import statements are a frequent cause of confusion and bugs in Rust code. They currently exist behind a feature gate, so there is already some pressure against them.

I suggest removing them completely. The only thing I can think of that would be a significant issue about removing the glob functionality would be how it affects the prelude. However, we could just special case prelude functionality.

The advantage of this is that would make the resolution algorithm much simpler, since the glob import functionality adds significant complexity.

cc @pcwalton

[ketsuban]

I suggest allowing module writers to define a list of names which a glob-import would pull into the target namespace, and emit an error if the module is glob-imported but does not define one. The model here is the __all__ magic in Python, which tends to be underused entirely because Python otherwise defaults to importing everything defined in the module namespace.

The main use case for glob-importing seems to be easing the fingers of the user when following good practice in breaking their code into multiple crates; this covers that without the unfortunate consequences in every other situation which lead people to call for eliminating glob-imports entirely.

[steveklabnik]

Glob imports are now stable, and so I'm going to give this a close.

[Kimundi]

But not bug free, sadly :P

[steveklabnik]

What software is? Anyway, bugs should certainly be filed in rust-lang/rust