actions_base: add auto-registration to reflect_action by Priyanshi507 · Pull Request #7298 · TheHPXProject/hpx

Priyanshi507 · 2026-05-27T12:57:05Z

Summary

reflect_action now automatically registers its invocation counter
via a static register_action_invocation_count member — eliminating
the need for HPX_REGISTER_ACTION for reflection-based plain actions.

Design

Follows HPX's existing auto-registration pattern already used by
register_action<Action> in register_action.hpp:

template <std::meta::info F>
struct reflect_action : basic_action<...> {
    // Auto-registers during static initialization
    static detail::register_action_invocation_count<reflect_action<F>>
        invocation_count_registrar_;
};

What's still needed

The explicit transfer_action<reflect_action<F>> instantiation
(for shared library export) still requires HPX_REGISTER_ACTION
in non-reflection builds. For reflection builds, users can omit
HPX_REGISTER_ACTION entirely.

Depends on

PR actions_base: add reflection-based action definition (reflect_action) #7266 (merged) — reflect_action core
PR actions_base: integrate reflect_action with basic_action #7281 (merged) — basic_action integration

Checklist

I have added a new feature and have added tests to go along with it.

reflect_action now includes a static register_action_invocation_count member that automatically registers the action's invocation counter during static initialization — no HPX_REGISTER_ACTION call needed. This follows HPX's existing auto-registration pattern (already used by register_action<Action> in register_action.hpp) and eliminates boilerplate for reflection-based plain actions. The explicit transfer_action instantiation (for shared library export) still requires HPX_REGISTER_ACTION for non-reflection builds, but reflect_action users can omit it entirely. Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

StellarBot · 2026-05-27T13:00:04Z

Can one of the admins verify this patch?

Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

codacy-production · 2026-05-27T13:06:56Z

Up to standards ✅

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Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

Add Derived template parameter following the same pattern as plain_action for future extensibility: template <std::meta::info F, typename Derived = void> struct reflect_action : basic_action<detail::plain_function, func_type, detail::action_type_t<reflect_action<F, Derived>, Derived>> This allows user-defined types to derive from reflect_action<F> to customize behavior, matching the extensibility of make_action_t. Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

…strar_ Both the in-class declaration and out-of-class definition of invocation_count_registrar_ now consistently use reflect_action<F, Derived>. Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

…trar_ Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

hkaiser

Otherwise, LGTM, thanks!

Inside reflect_action's class body, 'reflect_action' refers to 'reflect_action<F, Derived>' via the injected class name, so we can simplify: - action_type_t<reflect_action<F, Derived>, Derived> -> action_type_t<reflect_action, Derived> - register_action_invocation_count<reflect_action<F, Derived>> -> register_action_invocation_count<reflect_action> Suggested by hkaiser. Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

hkaiser

LGTM, thanks!

…t_action) Summary Extends reflect_action with reflect_component_action<F> — a C++26 reflection-based replacement for HPX_DEFINE_COMPONENT_ACTION. Before (3 manual steps): HPX_DEFINE_COMPONENT_ACTION(server, compute, compute_action) HPX_REGISTER_ACTION_DECLARATION(compute_action) HPX_REGISTER_ACTION(compute_action) After (single line): HPX_COMPONENT_ACTION(server, compute, compute_action); Design - reflect_component_action_base<F> extracts component_type via parent_of(F) and func_type via type_of(F) — two-step workaround following the same pattern as reflect_action_base<F> - reflect_component_action<F, Derived> inherits from basic_action<component_type, func_type, action_type_t<...>> - Auto-registration via static invocation_count_registrar_ member following the same pattern as reflect_action<F> - HPX_COMPONENT_ACTION(component, func, name) macro as cross-compiler fallback (GCC trunk + Clang P2996) Depends on - PR TheHPXProject#7298 (merged) — reflect_action with Derived parameter Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

Adds a new section to migration_guide.rst documenting the transition from HPX's traditional macro-based action API to the new C++26 reflection-based API introduced in PRs TheHPXProject#7298, TheHPXProject#7311, and TheHPXProject#7342. Covers: - Build requirements (GCC trunk, Clang P2996, CMake flag) - Transparent migration: existing HPX_PLAIN_ACTION/HPX_DEFINE_COMPONENT_ACTION code requires zero source changes when HPX_WITH_CXX26_REFLECTION=ON - Explicit migration examples for plain, component, and direct actions - Overloaded function handling (keep existing macros) - Compile-time properties exposed by reflection-based action types (arity, func_ptr_type, func_ptr) Part of GSoC 2026: Use C++26 Reflection for HPX Remote Operations. Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

Adds a new hpx::async overload that accepts a std::meta::info reflection of a free function as a non-type template parameter, eliminating the need to define an explicit action type: // Before: explicit action type required using my_action = hpx::actions::reflect_action<^^app::compute>; hpx::async<my_action>(target, args...); // After: direct reflection syntax hpx::async<^^app::compute>(target, args...); The overload is constrained to accept only viable distributed targets (hpx::id_type, client types, distribution policies), matching the existing async_action_dispatch specializations. Internally it constructs reflect_action<F>{} and delegates to the existing hpx::async(action, target, ...) machinery — no changes to dispatch internals required. Guarded by HPX_HAVE_CXX26_REFLECTION. Suggested by hkaiser as a natural extension of the reflection-based action work from PRs TheHPXProject#7298, TheHPXProject#7311, TheHPXProject#7342, TheHPXProject#7349. Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

Priyanshi507 requested a review from hkaiser as a code owner May 27, 2026 12:57

actions_base: add test for reflect_action auto-registration member

47ddeda

Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

actions_base: add missing type_traits include in reflect_action_test

4109be3

Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

Priyanshi507 added 2 commits May 27, 2026 15:18

actions_base: fix non-ASCII em dash in reflect_action.hpp comment

1c89097

Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

actions_base: fix remaining non-ASCII em dash in comment

b3c8b77

Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

hkaiser added type: enhancement category: actions type: compatibility issue labels May 27, 2026

hkaiser reviewed May 27, 2026

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Comment thread libs/full/actions_base/include/hpx/actions_base/reflect_action.hpp Outdated

Priyanshi507 added 2 commits May 27, 2026 18:05

actions_base: fix Derived type inconsistency in invocation_count_regi…

624d94f

…strar_ Both the in-class declaration and out-of-class definition of invocation_count_registrar_ now consistently use reflect_action<F, Derived>. Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

Priyanshi507 mentioned this pull request May 27, 2026

Fixing various smaller issues in build system #7299

Merged

actions_base: fix malformed template syntax in invocation_count_regis…

a9cb2d2

…trar_ Signed-off-by: Priyanshi507 <hiiuiuiabi@gmail.com>

hkaiser previously approved these changes May 27, 2026

View reviewed changes

Comment thread libs/full/actions_base/include/hpx/actions_base/reflect_action.hpp Outdated

Comment thread libs/full/actions_base/include/hpx/actions_base/reflect_action.hpp Outdated

hkaiser added this to the 2.0.0 milestone May 27, 2026

Priyanshi507 dismissed hkaiser’s stale review via be7ecae May 28, 2026 09:20

hkaiser approved these changes May 28, 2026

View reviewed changes

hkaiser merged commit 275a67d into TheHPXProject:master May 28, 2026
73 checks passed

Priyanshi507 mentioned this pull request Jun 2, 2026

actions_base: add reflection-based component action (reflect_component_action) #7311

Merged

1 task

Priyanshi507 mentioned this pull request Jul 4, 2026

docs: add C++26 reflection-based action migration guide #7348

Merged

Priyanshi507 mentioned this pull request Jul 13, 2026

async: add hpx::async<^^func>(target, ...) reflection overload #7376

Merged

Priyanshi507 mentioned this pull request Jul 17, 2026

components: add reflect_client<^^Server> and HPX_REFLECT_CLIENT macro #7385

Merged

Priyanshi507 mentioned this pull request Jul 29, 2026

actions_base: annotation-driven action registration via C++26 reflection #7418

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actions_base: add auto-registration to reflect_action - #7298

actions_base: add auto-registration to reflect_action#7298
hkaiser merged 9 commits into
TheHPXProject:masterfrom
Priyanshi507:reflect-action-auto-register

Priyanshi507 commented May 27, 2026

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codacy-production Bot commented May 27, 2026 •

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Priyanshi507 commented May 27, 2026

Summary

Design

What's still needed

Depends on

Checklist

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StellarBot commented May 27, 2026

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Up to standards ✅

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codacy-production Bot commented May 27, 2026 •

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