Tracking issue for Allow a re-export for main (RFC 1260)

[aturon]

RFC Thread:
rust-lang/rfcs#1260

Feature name:
imported_main

Steps / History

• Implementation:
  • Support imported main from same crate (Implement RFC 1260 with feature_name imported_main. #84401)
  • Support imported main from foreign crate (Add primary marker on codegen unit and generate main wrapper on primary codegen. #84507)
• Final commenting period (FCP) (Tracking issue for Allow a re-export for main (RFC 1260) #28937 (comment))
• Stabilization PR (Stabilize imported_main #122060)

[steveklabnik]

Triage: no change.

[bombless]

bombless@3d891e7
The patch should be pretty small so I wonder if we need a feature-gate for it.

[petrochenkov]

This RFC was implemented in #84401.

[crlf0710]

#84401 has landed. Want to say thank you to @petrochenkov for your patient mentoring!

There's a small piece of codegen changes to support foreign crate imported main fn case. The PR is now up at #84507 .

[crlf0710]

#84507 has landed and this rfc is now fully implemented.

[joshtriplett]

@crlf0710 What's the current state of this? Are people using it successfully? Is it a potential candidate for stabilization?

[crlf0710]

@joshtriplett It's fully implemented, and the tests pass. There're no known technical limitations, but I'm not aware whether there're people using it today in nightly builds. I think it's a potential candidate for stablization.

[pnkfelix]

Discussed at today's T-compiler backlog bonanza.

@rustbot label +T-lang +I-lang-nominated

Its not clear from discussion whether its appropriate to shift this to S-tracking-ready-to-stabilize, or if it is S-tracking-needs-to-bake

[clubby789]

I think this should be stabilized.

Stabilization Report

Summary

The imported_main feature allows a function to be re-exported as main. This allows, for example, re-exporting a function from a library and using it as the entrypoint.

pub mod foo {
    pub fn bar() {
        println!("Hello, world!");
    }
}
use foo::bar as main;

Tests/Edge Cases

The feature is tested in tests/ui/entry-point:
- Exporting from a module in the current crate
- Exporting from an extern crate
- Incorrectly typed functions are not allowed
- Conflicting mains are not allowed

Documentation PRs

• The Reference: Document importing main reference#1461
  There are no known issues or unresolve questions.

[joshtriplett]

@rfcbot merge

[rfcbot]

Team member @joshtriplett has proposed to merge this. The next step is review by the rest of the tagged team members:

• @joshtriplett
• @nikomatsakis
• @pnkfelix
• @scottmcm
• @tmandry

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

cc @rust-lang/lang-advisors: FCP proposed for lang, please feel free to register concerns.
See this document for info about what commands tagged team members can give me.

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

[rfcbot]

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

[slanterns]

I guess we can close it now?

[crlf0710]

Closed by #122060