rt: Mention LocalRuntime in the new_current_thread builder

[mattiapitossi]

Motivation

I notice we don't mention the LocalRuntime on the new_current_thread docs in the Runtime Builder.

Solution

Mention the possibility to spawn non-Send task on the current thread runtime with LocalRuntime.

[Darksonn]

Thanks!

[martin-g]

I wanted to test that (unstable) is not used as a target for [LocalRuntime] - it is not! All good here!

But "[LocalRuntime]: crate::runtime::LocalRuntime" and "[build_local]: crate::runtime::Builder::build_local" below are broken for me.

cargo doc reports many broken items:

 cargo doc
warning: unresolved link to `task::Builder`
   --> tokio/src/lib.rs:357:9
    |
357 | //! - [`task::Builder`]
    |         ^^^^^^^^^^^^^ no item named `Builder` in module `task`
    |
    = note: `#[warn(rustdoc::broken_intra_doc_links)]` on by default

warning: unresolved link to `runtime::Builder::on_task_spawn`
   --> tokio/src/lib.rs:360:9
    |
360 | //! - [`runtime::Builder::on_task_spawn`]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the struct `Builder` has no field or associated item named `on_task_spawn`

warning: unresolved link to `runtime::Builder::on_task_terminate`
   --> tokio/src/lib.rs:361:9
    |
361 | //! - [`runtime::Builder::on_task_terminate`]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the struct `Builder` has no field or associated item named `on_task_terminate`

warning: unresolved link to `runtime::Builder::unhandled_panic`
   --> tokio/src/lib.rs:362:9
    |
362 | //! - [`runtime::Builder::unhandled_panic`]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the struct `Builder` has no field or associated item named `unhandled_panic`

warning: public documentation for `tokio` links to private item `runtime::TaskMeta`
   --> tokio/src/lib.rs:363:9
    |
363 | //! - [`runtime::TaskMeta`]
    |         ^^^^^^^^^^^^^^^^^ this item is private
    |
    = note: this link will resolve properly if you pass `--document-private-items`
    = note: `#[warn(rustdoc::private_intra_doc_links)]` on by default

warning: unresolved link to `windows::named_pipe`
  --> tokio/src/net/mod.rs:28:42
   |
28 | //! [`tokio::net::windows::named_pipe`]: windows::named_pipe
   |                                          ^^^^^^^^^^^^^^^^^^^ no item named `windows` in scope

warning: public documentation for `runtime` links to private item `crate::runtime::Builder::disable_lifo_slot`
   --> tokio/src/runtime/mod.rs:366:35
    |
366 | //! [the lifo slot optimization]: crate::runtime::Builder::disable_lifo_slot
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this item is private
    |
    = note: this link will resolve properly if you pass `--document-private-items`

warning: unresolved link to `crate::runtime::RuntimeMetrics::worker_mean_poll_time`
   --> tokio/src/runtime/mod.rs:368:32
    |
368 | //! [`worker_mean_poll_time`]: crate::runtime::RuntimeMetrics::worker_mean_poll_time
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the struct `RuntimeMetrics` has no field or associated item named `worker_mean_poll_time`

warning: public documentation for `runtime` links to private item `crate::runtime::Builder::disable_lifo_slot`
   --> tokio/src/runtime/mod.rs:365:28
    |
365 | //! [`disable_lifo_slot`]: crate::runtime::Builder::disable_lifo_slot
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this item is private
    |
    = note: this link will resolve properly if you pass `--document-private-items`

warning: unresolved link to `crate::runtime::Builder::build_local`
   --> tokio/src/runtime/builder.rs:245:26
    |
245 |     /// [`build_local`]: crate::runtime::Builder::build_local
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the struct `Builder` has no field or associated item named `build_local`

warning: unresolved link to `crate::runtime::LocalRuntime`
   --> tokio/src/runtime/builder.rs:244:27
    |
244 |     /// [`LocalRuntime`]: crate::runtime::LocalRuntime
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no item named `LocalRuntime` in module `runtime`

warning: unresolved link to `crate::runtime::LocalRuntime`
   --> tokio/src/task/local.rs:395:27
    |
395 |     /// [`LocalRuntime`]: struct@crate::runtime::LocalRuntime
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no item named `LocalRuntime` in module `runtime`

warning: unresolved link to `crate::runtime::LocalRuntime`
   --> tokio/src/task/join_set.rs:183:27
    |
183 |     /// [`LocalRuntime`]: crate::runtime::LocalRuntime
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no item named `LocalRuntime` in module `runtime`

warning: `tokio` (lib doc) generated 13 warnings
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.10s
   Generated /home/martin/git/rust/tokio/target/doc/tests_build/index.html and 7 other files

@Darksonn Maybe these should be fixed for 1.49.0 ?

[Darksonn]

Docs should be built with unstable features enabled. I suspect the links are not broken in that case.

[martin-g]

Right! Thanks!

With --cfg tokio_unstable only two links are not resolved:

$ RUSTDOCFLAGS="--cfg tokio_unstable" cargo doc --open
...
warning: unresolved link to `task::Builder`
   --> tokio/src/lib.rs:357:9
    |
357 | //! - [`task::Builder`]
    |         ^^^^^^^^^^^^^ no item named `Builder` in module `task`
    |
    = note: `#[warn(rustdoc::broken_intra_doc_links)]` on by default

warning: unresolved link to `windows::named_pipe`
  --> tokio/src/net/mod.rs:28:42
   |
28 | //! [`tokio::net::windows::named_pipe`]: windows::named_pipe
   |                                          ^^^^^^^^^^^^^^^^^^^ no item named `windows` in scope

warning: `tokio` (lib doc) generated 2 warnings

Let me compare it with the CI job to see what else I might be missing!

[martin-g]

https://github.com/tokio-rs/tokio/actions/runs/20660332515/job/59321300223?pr=7820 looks good!

False alarm! Sorry!