feat(anyspawn)!: add CustomSpawnerBuilder for composing multilayered spawner

[Vaiz]

No description provided.

[github-actions]

⚠️ Breaking Changes Detected

--- failure method_parameter_count_changed: pub method parameter count changed ---

Description:
A publicly-visible method now takes a different number of parameters, not counting the receiver (self) parameter.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#fn-change-arity
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.46.0/src/lints/method_parameter_count_changed.ron

Failed in:
  anyspawn::Spawner::new_custom now takes 2 parameters instead of 1, in /home/runner/work/oxidizer/oxidizer/crates/anyspawn/src/spawner.rs:154

If the breaking changes are intentional then everything is fine - this message is merely informative.

Remember to apply a version number bump with the correct severity when publishing a version with breaking changes (1.x.x -> 2.x.x or 0.1.x -> 0.2.x).

[Copilot]

Pull request overview

Adds a composable, named custom spawner builder to anyspawn, improving debug output and enabling layered spawn behavior (e.g., context propagation) while updating the existing custom spawner API to include a stable name.

Changes:

• Introduce CustomSpawnerBuilder for composing named layers and building a Spawner.
• Make custom spawners and Spawner debug output include spawner/layer names; update Spawner::new_custom to accept a name.
• Add tests (incl. snapshots) and an OpenTelemetry context propagation example; update docs/README/benches accordingly.

Reviewed changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
crates/anyspawn/tests/spawner.rs	Updates tests for new Spawner::new_custom(name, ...) API and debug output expectations.
crates/anyspawn/tests/builder.rs	Adds snapshot + behavioral tests for builder/spawner naming and debug output.
crates/anyspawn/src/spawner.rs	Adds named new_custom, internal new_with_layers, and custom Debug for Spawner.
crates/anyspawn/src/lib.rs	Exposes CustomSpawnerBuilder and BoxedFuture behind custom feature; updates docs.
crates/anyspawn/src/custom.rs	Extends CustomSpawner to carry name/layer metadata and improved Debug.
crates/anyspawn/src/builder.rs	Adds CustomSpawnerBuilder implementation (layering + build).
crates/anyspawn/examples/otel_context.rs	New example demonstrating OpenTelemetry context propagation via a layer.
crates/anyspawn/examples/custom.rs	Updates example to provide a custom spawner name.
crates/anyspawn/benches/spawner.rs	Updates benchmark custom spawner creation to include name.
crates/anyspawn/README.md	Updates README example and feature list to mention builder.
crates/anyspawn/Cargo.toml	Adds dev-deps (insta, opentelemetry) and registers new example.
Cargo.lock	Pulls in new dev dependency entries.
.spelling	Adds “typestate” to spelling dictionary.

Comments suppressed due to low confidence (1)

crates/anyspawn/src/spawner.rs:12

• Future is referenced in the spawn method signature (impl Future<Output = T>) but std::future::Future is not imported anywhere in this module. This is a compile error; add use std::future::Future; (or use std::future::Future in the signature).

use std::fmt::{self, Debug};
#[cfg(feature = "custom")]
use std::sync::Arc;

#[cfg(feature = "custom")]
use crate::custom::{BoxedFuture, CustomSpawner};
use crate::handle::JoinHandle;

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.0%. Comparing base (6ec4849) to head (f89d667).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #308   +/-   ##
=======================================
  Coverage   100.0%   100.0%           
=======================================
  Files         152      153    +1     
  Lines        9337     9401   +64     
=======================================
+ Hits         9337     9401   +64     

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[Copilot]

Pull request overview

Copilot reviewed 12 out of 13 changed files in this pull request and generated 1 comment.

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[martintmk]

What is the indented audience for this change? For example, when using directly types form oxidizer runtime, my expectation is that context propagation is handled transparently, or do I have to use spawner to preserve it?

[Vaiz]

What is the indented audience for this change? For example, when using directly types from oxidizer runtime, my expectation is that context propagation is handled transparently, or do I have to use spawner to preserve it?

unfortunately, otel context is not automatically propagated to child tasks/new threads. It has to be done manually

[schgoo]

What other use cases would use this abstraction? Could we solve this by integrating OTel directly?

[Vaiz]

What other use cases would use this abstraction? Could we solve this by integrating OTel directly?

I think in general it's a useful abstraction to have for everyone who wants to track/intercept spawned tasks in some way

for example:

• count number of tasks
• wrap them to track poll/pending time
• throttle
• many other use cases

[Copilot]

Pull request overview

Copilot reviewed 12 out of 13 changed files in this pull request and generated 4 comments.

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