Implement P2300 bulk adapter for HPX executors

[shivansh023023]

P2300 bulk Integration for HPX Executors

Description

This PR implements the P2300 bulk sender adapter specifically for HPX's legacy executors, including the parallel_executor and sequenced_executor. By bridging the hpx::execution::experimental::bulk algorithm with HPX's internal bulk_sync_execute mechanism, this change ensures that data-parallel workloads are properly load-balanced and optimized using HPX's high-performance partitioners.

Key Technical Improvements:

• Algorithmic Bridging: Successfully mapped the C++23 bulk sender to the underlying HPX execution engine for native parallel performance.
• Robust tag_invoke Overloads: Implemented a full suite of connect_t overloads (supporting &&, &, and const&) to ensure compatibility with consumer algorithms like sync_wait.
• Reference Stability: Utilized std::decay_t within the bulk_receiver to prevent reference collapsing and ensure the safety of deferred functional object execution.
• Architectural Integrity: Resolved a potential circular dependency by situating the implementation within the executors module rather than the core execution module.

Proposed Changes

• [New] libs/core/executors/include/hpx/executors/executor_scheduler_bulk.hpp: Implements executor_bulk_sender and executor_bulk_receiver.
• [Modified] libs/core/executors/include/hpx/executors/executor_scheduler.hpp: Exposes get_completion_scheduler_t for ADL discovery.
• [Modified] libs/core/executors/include/hpx/executors/parallel_executor.hpp & sequenced_executor.hpp: Integrated the new bulk headers.
• [New Test] libs/core/executors/tests/unit/executor_algorithm_bulk.cpp: Comprehensive validation for sequential and parallel policies.

Background context

This work is part of the ongoing effort to modernize HPX's execution model to align with the C++23 Sender/Receiver (P2300) standard. Implementing bulk is a "Big Impact" milestone because it allows modern asynchronous pipelines to tap into the mature, multi-threaded performance of the HPX runtime.

Checklist

• I have added a new feature and have added tests to go along with it.
• I have verified the implementation with a local build of the executor_algorithm_bulk_test target.
• I have ensured all includes are strictly alphabetically sorted to comply with the HPX inspect tool.

[StellarBot]

Can one of the admins verify this patch?

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

_{NEW Get contextual insights on your PRs based on Codacy's metrics, along with PR and Jira context, without leaving GitHub. Enable AI reviewer
TIP This summary will be updated as you push new changes.}

[hkaiser]

@shivansh023023 Just FYI, before you invest more time into our old sender/receiver implementation: #7123 will soon remove almost all of our code related to this. Please focus your efforts on whatever stays after this has been merged.