Add public type aliases for detail types in when_any/when_all APIs

[mvandeberg]

Addresses #160. Public function signatures referenced detail:: types that users cannot name without reaching into the detail namespace. Add awaitable_result_type, when_any_result_type, and when_all_result_type as public aliases, and update all when_any and when_all signatures to use them. Simplify when_any_variant_t and when_any_state to use a flat parameter pack instead of requiring the first type separately.

Summary by CodeRabbit

• New Features

  • Made awaitable_result_t publicly available for direct use.
  • Added non-void tuple utility to produce void or compact tuples for multi-awaitable results.

• Refactor

  • Simplified when_any to a single variadic overload returning a variant of awaitable results.
  • Streamlined when_all to return void when all awaitables are void and a concise tuple otherwise.

• Documentation

  • Updated docs to clarify new public types and when_all/when_any behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 449422eb-9cdb-4064-9060-3dbbc4a166e2

📥 Commits

Reviewing files that changed from the base of the PR and between 542f0b2 and 2281eb3.

⛔ Files ignored due to path filters (1)

• test/unit/when_all.cpp is excluded by !**/test/**

📒 Files selected for processing (4)

• example/async-mutex/async_mutex.cpp
• include/boost/capy/concept/io_awaitable.hpp
• include/boost/capy/when_all.hpp
• include/boost/capy/when_any.hpp

💤 Files with no reviewable changes (1)

• example/async-mutex/async_mutex.cpp

---

📝 Walkthrough

Walkthrough

Exposes awaitable_result_t publicly, adds non_void_tuple_t and replaces when_all_result_t, simplifies when_any to a single variadic API returning a positional std::variant over awaitable results, and removes an unused local constexpr in an example.

Changes

Cohort / File(s)	Summary
Type Alias Exposure include/boost/capy/concept/io_awaitable.hpp	Moved awaitable_result_t from detail into boost::capy as a documented public alias: template<typename A> using awaitable_result_t = decltype(std::declval<std::decay_t<A>&>().await_resume());.
when_all Result Type Refactor include/boost/capy/when_all.hpp	Removed when_all_result_t; added public non_void_tuple_t<Ts...> that filters out void (yields void if all are void); updated when_all return and internal aliases to use non_void_tuple_t<awaitable_result_t<As>...>.
when_any API Simplification include/boost/capy/when_any.hpp	Replaced when_any(A0, As...) with single variadic when_any(As...) (requires at least one); public return type changed to task<std::variant<void_to_monostate_t<awaitable_result_t<As>>...>>; removed detail::when_any_variant_t and updated state/template/task_count/aliases accordingly.
Example Cleanup example/async-mutex/async_mutex.cpp	Removed an unused local constexpr int num_workers = 6; no runtime behavior changes (workers still referenced directly).

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related issues

• when_all: replace void filtering with monostate to preserve task-index-to-result-index mapping #204: Related — touches when_all/awaitable-result typing; this PR implements non_void_tuple_t as the void-filtering approach.

Possibly related PRs

• Feature: when_any #101: Strongly related — also exposes/moves awaitable_result_t and adjusts when_any/when_all signatures.
• The usual suspects #125: Strongly related — updates public aliases and replaces detail::awaitable_result_t usages across when_any/when_all.
• Update when_all to operate on IoAwaitable #146: Strongly related — similar changes to awaitable result extraction and when_all/when_any API wiring.

Poem

🐰 I hopped through headers late at night,

Pulled awaitable_result_t into the light,
when_any flattened to a single spread,
when_all trims voids to tuck them bed,
A rabbit's tidy change — all types sleep tight.

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Add public type aliases for detail types in when_any/when_all APIs' clearly and directly summarizes the main change: exposing previously internal detail types through public aliases.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[cppalliance-bot]

An automated preview of the documentation is available at https://203.capy.prtest3.cppalliance.org/index.html

If more commits are pushed to the pull request, the docs will rebuild at the same URL.

2026-03-04 21:41:43 UTC

[cppalliance-bot]

GCOVR code coverage report https://203.capy.prtest3.cppalliance.org/gcovr/index.html
LCOV code coverage report https://203.capy.prtest3.cppalliance.org/genhtml/index.html
Coverage Diff Report https://203.capy.prtest3.cppalliance.org/diff-report/index.html

Build time: 2026-03-04 21:55:51 UTC

[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@include/boost/capy/when_any.hpp`:
- Around line 562-563: Remove the Javadoc `@tparam As` entry for the variadic
template pack and leave the `@param as` description intact; specifically, in the
when_any async variadic overload in when_any.hpp delete the `@tparam As
Awaitable types (each must satisfy IoAwaitable).` line and, if needed, move any
concept requirement text into the main description (not as a `@tparam`) so the
variadic pack As is not documented with a `@tparam` tag.
- Around line 578-580: The variadic when_any template currently permits zero
arguments, yielding an invalid empty std::variant; change the template signature
to require at least one awaitable (e.g., replace template<IoAwaitable... As>
with template<IoAwaitable A0, IoAwaitable... As> and adjust the return type to
use A0, As... with void_to_monostate_t<awaitable_result_t<...>> so an empty pack
is impossible), and update occurrences referencing when_any accordingly; also
remove the `@tparam` As line from the function javadoc to follow the guideline
that variadic template parameters should not be documented.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 249b7904-5bbf-4f1c-a78a-5183ea0e790e

📥 Commits

Reviewing files that changed from the base of the PR and between 2d4c01f and fa28e43.

⛔ Files ignored due to path filters (1)

• test/unit/when_all.cpp is excluded by !**/test/**

📒 Files selected for processing (4)

• example/async-mutex/async_mutex.cpp
• include/boost/capy/concept/io_awaitable.hpp
• include/boost/capy/when_all.hpp
• include/boost/capy/when_any.hpp

💤 Files with no reviewable changes (1)

• example/async-mutex/async_mutex.cpp

[coderabbitai]

♻️ Duplicate comments (1)

include/boost/capy/when_any.hpp (1)

562-563: ⚠️ Potential issue | 🟡 Minor

Remove variadic @tparam As from this async overload docblock.

Line 562 still documents variadic template args with @tparam, which violates the async javadoc rule for variadic packs.

📝 Suggested doc edit

-    `@tparam` As Awaitable types (each must satisfy IoAwaitable).
     `@param` as Awaitables to race concurrently.

As per coding guidelines: "Document tparam in async/awaitable function javadoc for non-variadic template parameters, stating concept requirements and not documenting variadic Args...".

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@include/boost/capy/when_any.hpp` around lines 562 - 563, Remove the variadic
template `@tparam` As entry from the async overload docblock in
include/boost/capy/when_any.hpp: locate the async overload's comment block (the
one that currently lists "@tparam As Awaitable types (each must satisfy
IoAwaitable)." above "@param as Awaitables to race concurrently.") and delete
the `@tparam` As line so the docblock no longer documents a variadic template
parameter; keep the `@param` as line and ensure only non-variadic template
parameters are documented elsewhere per the async/awaitable documentation rules.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Duplicate comments:
In `@include/boost/capy/when_any.hpp`:
- Around line 562-563: Remove the variadic template `@tparam` As entry from the
async overload docblock in include/boost/capy/when_any.hpp: locate the async
overload's comment block (the one that currently lists "@tparam As Awaitable
types (each must satisfy IoAwaitable)." above "@param as Awaitables to race
concurrently.") and delete the `@tparam` As line so the docblock no longer
documents a variadic template parameter; keep the `@param` as line and ensure only
non-variadic template parameters are documented elsewhere per the
async/awaitable documentation rules.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 55af6c93-6d31-4564-9375-dd1b7badcce8

📥 Commits

Reviewing files that changed from the base of the PR and between fa28e43 and b9ea7eb.

⛔ Files ignored due to path filters (1)

• test/unit/when_all.cpp is excluded by !**/test/**

📒 Files selected for processing (4)

• example/async-mutex/async_mutex.cpp
• include/boost/capy/concept/io_awaitable.hpp
• include/boost/capy/when_all.hpp
• include/boost/capy/when_any.hpp

💤 Files with no reviewable changes (1)

• example/async-mutex/async_mutex.cpp

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.89%. Comparing base (df92ffb) to head (2281eb3).
⚠️ Report is 13 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #203      +/-   ##
===========================================
+ Coverage    91.71%   91.89%   +0.18%     
===========================================
  Files           76       76              
  Lines         4488     4504      +16     
===========================================
+ Hits          4116     4139      +23     
+ Misses         372      365       -7     

Files with missing lines	Coverage Δ
include/boost/capy/when_all.hpp	97.95% <ø> (ø)
include/boost/capy/when_any.hpp	99.31% <ø> (+<0.01%)	⬆️

... and 6 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7715a31...2281eb3. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[coderabbitai]

♻️ Duplicate comments (1)

include/boost/capy/when_any.hpp (1)

562-563: ⚠️ Potential issue | 🟡 Minor

Remove variadic @tparam As from this async overload javadoc.

Line 562 still documents a variadic template pack with @tparam, which conflicts with the repo async-doc rule.

📝 Suggested doc fix

-    `@tparam` As Awaitable types (each must satisfy IoAwaitable; at least one required).
     `@param` as Awaitables to race concurrently (must not be empty).

As per coding guidelines: "Document tparam in async/awaitable function javadoc for non-variadic template parameters, stating concept requirements and not documenting variadic Args...".

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@include/boost/capy/when_any.hpp` around lines 562 - 563, The javadoc for the
async overload of when_any in include/boost/capy/when_any.hpp incorrectly
documents a variadic template pack with "@tparam As"; remove that variadic
"@tparam As" line from the async/awaitable overload's comment and instead ensure
the comment states the requirement in prose (e.g., "Awaitables to race
concurrently (must not be empty); each must satisfy IoAwaitable") next to the
"@param as" description for the when_any async overload so it conforms to the
repo async-doc rule.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Duplicate comments:
In `@include/boost/capy/when_any.hpp`:
- Around line 562-563: The javadoc for the async overload of when_any in
include/boost/capy/when_any.hpp incorrectly documents a variadic template pack
with "@tparam As"; remove that variadic "@tparam As" line from the
async/awaitable overload's comment and instead ensure the comment states the
requirement in prose (e.g., "Awaitables to race concurrently (must not be
empty); each must satisfy IoAwaitable") next to the "@param as" description for
the when_any async overload so it conforms to the repo async-doc rule.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 5527a05e-752d-450a-93ed-fe3112e1413d

📥 Commits

Reviewing files that changed from the base of the PR and between b9ea7eb and 542f0b2.

⛔ Files ignored due to path filters (1)

• test/unit/when_all.cpp is excluded by !**/test/**

📒 Files selected for processing (4)

• example/async-mutex/async_mutex.cpp
• include/boost/capy/concept/io_awaitable.hpp
• include/boost/capy/when_all.hpp
• include/boost/capy/when_any.hpp

💤 Files with no reviewable changes (1)

• example/async-mutex/async_mutex.cpp