Proxy 4.0.1 Release

4.0.1 is a focused patch: it introduces a small but foundational substitution_dispatch API (formalizing what "upward conversion" tried to express), tightens proxy_view & skills::as_view semantics to prevent accidental lifetime bugs, and fixes facade‑aware view behavior. It also refreshes the spec/docs and updates CI.

What's Changed

• Fix proxy_view with facade-aware overloads by @mingxwa in #347
• Forbid conversion from rvalue of proxy to proxy_view by @mingxwa in #352
• Fix NVHPC pipeline by @mingxwa in #354
• Introduce new API: substitution_dispatch by @mingxwa in #353
• Revise documentation by @mingxwa in #355

Full Changelog: 4.0.0...4.0.1

Proxy 4.0.0 — Skills, semantics, and better codegen 🚀

Proxy 4 focuses on a composable skills API, refined core semantics for the basic building blocks, and leaner code generation. It remains header-only and keeps 3.x coexistence paths introduced in 3.4.0.

New: a refreshed documentation site at https://microsoft.github.io/proxy/ and out-of-the-box availability on Compiler Explorer. Proxy now also supports the Intel oneAPI C++ compilers in CI.

What's inside

• Skills and builder

  • basic_facade_builder gains add_skill and moves feature toggles into pro::skills (format, wformat, rtti, as_view, as_weak, slim). [#285]
  • {fmt} integration via proxy_fmt.h with pro::skills::fmt_format and fmt_wformat (requires {fmt} >= 6.1; include <proxy/proxy.h> and {fmt} before proxy_fmt.h). [#287]

• Core semantics and ergonomics

  • proxy::facade_type alias and stricter polymorphic ctor/assignment constraints (pointer-like only). [#278]
  • proxy_invoke now passes the proxy reference to indirect function pointers, enabling leaner call sequences around indirect calls; removed deprecated PRO_DEF_WEAK_DISPATCH (since 3.2.0).
  • Improved design contracts: removed access_proxy and proxiable_ptr_constraints; refined ProAccessible, ProBasicFacade, ProFacade, ProDispatch, and ProOverload requirements; accessing a null proxy is erroneous behavior; updated spec and tests. [#320, #336]
  • proxy_indirect_accessor is no longer copyable/movable to prevent misuse; added tests. [#335]
  • Introduced is_bitwise_trivially_relocatable and updated dispatch/pointer internals to support bitwise trivially relocatable but non-movable types. We did not adopt the C++26 "trivially relocatable" model; Proxy follows the "bitwise trivially relocatable" direction to preserve memcpy-based relocation semantics (see P3780R0). [#330]
  • Fixed prefix ++/-- to return proxy& (like assignment operators). [#332]
  • weak_proxy supports upward conversion. [#286]

• C++20 modules

  • Introduced C++20 module interface files (.ixx) and separated convenience macros to support modules. A huge thanks to @SidneyCogdill for leading this effort. See the modules support docs for usage caveats and current CMake module export limitations. [#293]

• Code generation

  • Leaner indirect call paths via proxy_invoke adjustments reduce surrounding instructions. [#280]
  • Builds where <format> is unavailable are supported; features that need formatting are conditional. [#289]

• Toolchain and CI

  • Clang upgraded to 20 in CI; fixed build with GCC trunk; added Intel oneAPI pipeline; updated NVHPC; improved libc++ compatibility. [#282, #327, #333]

• Docs and site

  • New docs site (MkDocs) with dark theme and improved navigation. See the FAQ for major upgrade guidance. Extracted example code from docs; updated sample links. [#299, #331, #311, #291, #328]
  • clang-format applied and enforced in CI; code and macro cleanup for standard naming. [#309, #314, #283, #316, #317]

Upgrading

Most users can update includes and CMake targets and rebuild. If you customized dispatches/skills or relied on old behaviors, see notes below.

• Headers and namespaces

  • Preferred include: <proxy/proxy.h>. Versioned headers remain under <proxy/v4/>. Code lives in pro::v4 inline namespace.

• CMake package/targets

  • New package/namespace: msft_proxy4. Example:
    • find_package(msft_proxy4 REQUIRED)
    • target_link_libraries(your_target PRIVATE msft_proxy4::proxy)
    • For the module interface, see docs; .ixx sources are shipped but export workflows vary by toolchain.

• Builder and skills

  • basic_facade_builder::support(...) -> add_skill<...>(). Feature toggles are in pro::skills (e.g., pro::skills::rtti, ::as_view, ::as_weak, ::fmt_format).
  • New header proxy_fmt.h for {fmt} skills; include <proxy/proxy.h> and {fmt} first.

• Removed and changed behaviors

  • PRO_DEF_WEAK_DISPATCH removed (deprecated since 3.2.0). Use standard dispatch patterns; weak fallbacks can call back into proxy.
  • Accessing a null proxy is erroneous behavior. Audit code paths that may dereference disengaged proxies.
  • proxy_indirect_accessor isn't copyable/movable; avoid storing *p; consume it immediately.
  • Relocatability: prefer pointer-like indirections if a type fails proxiable checks; see relocatability docs and is_bitwise_trivially_relocatable guidance.

• Formatting availability

  • If <format> is not available on your toolchain, Proxy will still build; only format-dependent skills/features are disabled. Use {fmt} skills if desired.

Refer to the updated docs and FAQ for side-by-side 3.x/4.x migration in large codebases, module usage notes, and relocatability guidance.

Acknowledgments

• What's Changed (selected PRs)

  • Fix typo in the spec of weak_facade by @mingxwa in #275
  • Remove offsetof to eliminate undefined behavior by @mingxwa in #276
  • Improve semantics of proxy by @mingxwa in #278
  • Improve proxy_invoke by @mingxwa in #280
  • Upgrade Clang version in the CI pipeline by @mingxwa in #282
  • Code clean up by @mingxwa in #283
  • Refactor basic_facade_builder by @mingxwa in #285
  • weak_proxy support upward conversion by @mingxwa in #286
  • Support build environments where <format> is not available by @mingxwa in #289
  • Add skills for {fmt} by @mingxwa in #287
  • Extract example code from docs by @mingxwa in #291
  • Separate macro definitions and add cppm files by @SidneyCogdill in #293
  • Project rename: Proxy -> Proxy 4 by @SidneyCogdill in #302
  • Make package name matches namespace name by @SidneyCogdill in #307
  • Apply clang-format by @mingxwa in #309
  • Revise documentation by @mingxwa in #299
  • Add FAQ for major version upgrade by @mingxwa in #311
  • Fix release pipeline by @mingxwa in #313
  • Apply clang-format to the whole repository by @mingxwa in #314
  • Code cleanup by @mingxwa in #316
  • Clean up macros by @mingxwa in #317
  • Improve design quality by @mingxwa in #320
  • Support trivial relocatability by @mingxwa in #321
  • Revise skills by @mingxwa in #324
  • Fix MSVC build in debug mode by @mingxwa in #329
  • Update sample code links by @mingxwa in #328
  • Fix build with GCC trunk by @mingxwa in #327
  • Support bitwise trivial relocatability by @mingxwa in #330
  • Allow dark theme on the website by @mingxwa in #331
  • Improve proxy_indirect_accessor by @mingxwa in #335
  • Fix return type for prefix operator++ and operator-- by @mingxwa in #332
  • Code cleanup by @mingxwa in #334
  • Improve toolchain coverage by @mingxwa in #333
  • Revise the semantics of ProAccessible by @mingxwa in #336
  • Fix release pipeline by @mingxwa in #337

• New Contributors

  • @SidneyCogdill made their first contribution in #293

Full changelog: 3.4.0...4.0.0

Proxy 3.4.0 – Forward-compatibility release 🚀

3.4.0 adds no new APIs, but it paves the way for Proxy 4 and later majors.

What’s inside

• Forward-compatibility scaffolding

  • Public headers now live in a versioned inline namespace (pro::v3).
  • Every macro has a major-qualified alias (e.g. PRO3_DEF_MEM_DISPATCH).
  • Lets two majors coexist in one translation unit without ODR violations.
  • Idea by @SidneyCogdill, implemented by @SidneyCogdill and @mingxwa.

• Toolchain fix

  • Resolved a build failure on Clang 20 — thanks @iKoznov.

Upgrading

1. Treat 3.4.0 like any other 3.x patch/minor update; no code changes required.

2. After Proxy 4 ships, migrate module-by-module:

   #include <proxy/v3/proxy.h>  // current
   #include <proxy/v4/proxy.h>  // new
   
   pro::v3::foo();  // existing code
   pro::v4::foo();  // migrated code

3. When every target depends only on v4, drop v3 and remove pro::v3:: qualifiers.

See the updated FAQ ("How do I upgrade Proxy in a large codebase?") for details.

Full changelog: 3.3.0...3.4.0

Proxy 3.3.0 Release

New Features 🌟

• Added facilities for shared/weak ownership by @mingxwa in #264:
  • function template make_proxy_shared: Similar to instantiating a proxy with std::shared_ptr, but
    • Without additional type-erasure on the deleter,
    • Having a more compact memory layout without requiring a separate control block,
    • Without weak ownership support if not desired.
  • function template allocate_proxy_shared: Similar to make_proxy_shared() while supports any custom allocators.
  • alias template weak_proxy and class template weak_facade: Specify proxy with weak ownership.
  • basic_facade_builder::support_weak: Specifies that a facade type F supports conversion from proxy<F> to weak_proxy<F>.
• function template make_proxy_view by @mingxwa in #265: Similar to creating a proxy_view from a raw pointer, but honors constness and reference semantics.
• concept proxiable_target by @mingxwa in #265: Specifies that a reference type can instantiate a proxy_view.

Quality Improvements 🔬

• Improved diagnostics by reducing constraints by @mingxwa in #262. Thanks to @SidneyCogdill for the great idea!
• Allowed creating proxy from a null pointer by @mingxwa in #260
• Prefered static operator() if available by @mingxwa in #267
• Constrained proxy with facade by @mingxwa in #263
• Switched lifetime convention to standard dispatch model by @mingxwa in #269
• Aligned behavior of direct and indirect proxy_invoke with rvalue reference by @mingxwa in #271

Toolchain Updates 🛠️

• Added benchmarks for shared ownership both in indirect invocation and lifetime management by @mingxwa in #264. Below are the numbers from a recent CI build:

	MSVC on Windows	GCC on Ubuntu	Clang on Ubuntu	Apple Clang on macOS	NVIDIA HPC on Ubuntu
Indirect invocation on small objects via proxy vs. virtual functions (shared ownership)	🟢proxy is about 327.6% faster	🟢proxy is about 83.2% faster	🟢proxy is about 46.1% faster	🟢proxy is about 26.8% faster	🟢proxy is about 75.5% faster
Indirect invocation on large objects via proxy vs. virtual functions (shared ownership)	🟢proxy is about 165.3% faster	🟢proxy is about 28.4% faster	🟢proxy is about 20.8% faster	🔴proxy is about 5.1% slower	🟢proxy is about 8.6% faster
Basic lifetime management for small objects with proxy (shared ownership) vs. std::shared_ptr (both without memory pool)	🟢proxy is about 11.8% faster	🟢proxy is about 10.8% faster	🟢proxy is about 8.5% faster	🟢proxy is about 37.5% faster	🟢proxy is about 8.8% faster
Basic lifetime management for small objects with proxy (shared ownership) vs. std::shared_ptr (both with memory pool)	🟢proxy is about 5.7% faster	🟡proxy is about 4.0% faster	🟢proxy is about 21.5% faster	🟢proxy is about 30.5% faster	🟡proxy is about 1.6% faster
Basic lifetime management for large objects with proxy (shared ownership) vs. std::shared_ptr (both without memory pool)	🟢proxy is about 21.1% faster	🟢proxy is about 6.0% faster	🟡proxy is about 0.4% slower	🟢proxy is about 48.9% faster	🟢proxy is about 8.7% faster
Basic lifetime management for large objects with proxy (shared ownership) vs. std::shared_ptr (both with memory pool)	🟢proxy is about 17.7% faster	🟢proxy is about 11.2% faster	🟢proxy is about 29.1% faster	🟢proxy is about 10.5% faster	🟡proxy is about 4.5% faster

• Attached environment information to benchmarking report by @mingxwa in #270
• Revised documentation for 3.3.0 by @mingxwa in #272

Full Changelog: 3.2.1...3.3.0

Proxy 3.2.1 Release

What's Changed

• Replaced basic_facade_builder::add_view<F> into support_view without requiring a template argument.
• Reduced the semantics of proxy_view.
• Added type facade_aware_overload_t. It allows specifying a facade-aware overload template (required for the implementation of basic_facade_builder::support_view).
• Revised the ProOverload requirements.

Full Changelog

3.2.0...3.2.1

• Improve documentation formatting by @mingxwa in #235
• Improve documentation formatting by @mingxwa in #236
• Add support for facade-aware overloads by @mingxwa in #239
• Code cleanup by @mingxwa in #251
• Fix swap for trivial proxy by @mingxwa in #249
• Improve proxy_view by @mingxwa in #241
• Bypass proxiability check in unresolved context by @mingxwa in #255
• Update version in CMake by @mingxwa in #256

Proxy 3.2.0 Release

What's Changed

New Features

• Added extension basic_facade_builder::support_rtti (enabling proxy_typeid and proxy_cast) for RTTI support as per @qq978358810 and @xuruilong100's feedback.
• Added extensions observer_facade, proxy_view and basic_facade_builder::add_view for non-owning proxy types as per @Shuenhoy's feedback.
• Added extensions std::formatter<proxy_indirect_accessor> and basic_facade_builder::support_format, enabling proxy to work with standard formatting functions such as std::format.
• Added class template weak_dispatch as a replacement of macro PRO_DEF_WEAK_DISPATCH (deprecated since 3.2).
• Added class template proxy_indirect_accessor, representing the dereferenced state of a proxy object.

Other Notable

• Revised the design of conversion_dispatch. In the previous version, conversion_dispatch was designed as a class template. It has been updated into 2 concrete types explicit_conversion_dispatch (aka. conversion_dispatch) and implicit_conversion_dispatch without a template.
• Revised the design of proxy_invoke and proxy_reflect.
• Fixed bug #219: ADL for free function accessors was broken for qualified overload resolution.
• Fixed bug #222: std::in_place_type_t overload resolution was broken when a dispatch is not SFINAE-safe.

Full Changelog

3.1.0...3.2.0

• Improve the release pipeline by @tian-lt in #210
• Update CMakeLists.txt to the latest version by @tian-lt in #211
• Revise design of conversion_dispatch by @mingxwa in #212
• Suppress unexpected compiler warnings by @mingxwa in #215
• Fix ADL for free function accessors by @mingxwa in #220
• Fix typo in implicit_conversion_dispatch.md by @mingxwa in #216
• Add support for proxy_view and complementary infrastructure by @mingxwa in #218
• Add direct support for RTTI by @mingxwa in #221
• Fix the std::in_place_type_t overload for SFINAE-unsafe facades by @mingxwa in #223
• Replace macro PRO_DEF_WEAK_DISPATCH with class template weak_dispatch by @mingxwa in #224
• Simplify proxy_invoke and proxy_reflect by @mingxwa in #226
• Feature: Support for std::format by @mingxwa in #228
• Revise spec for version 3.2 by @mingxwa in #231

Proxy 3.1.0 Release

What's Changed

• Added macro PRO_DEF_FREE_AS_MEM_DISPATCH to facilitate authoring a dispatch type of a free function, while providing accessibility through a member function.
• Improved accessibility for reflection. Specifically,
  • Added support for "accessors" in a custom reflector type. See function template proxy_reflect for more details.
  • Added support for "indirect" reflections, similar to conventions. See alias template basic_facade_builder::add_reflection for more details.
  • Added the named requirements ProReflection.
• Improved code generation in non-optimized builds to facilitate debugging. Specifically,
  • Added assertions against null pointers in proxy::proxy(), proxy_invoke(), and proxy_reflect().
  • Added guidance to encourage compilers to generate code for accessibility, even if they are not used in a binary (see #200 and #202 for more details).
  • Relaxed the named requirements ProAccessible to facilitate implementation of the debugging facilities.
• Added benchmarks for the library. See Analyzing the Performance of the “Proxy” Library for more details.
• Added support for the NVIDIA HPC compiler as per @pedronahum's feedback. Specifically,
  • Fixed unit tests to enable compilation with the NVIDIA HPC compiler.
  • Added a new validation pipeline to ensure it won't regress.
  • Updated README accordingly.
• Fixed unit tests when building with clang-cl on Windows as per @frederick-vs-ja's feedback.
• Improved documentation of some facilities. Specifically,
  • Aligned wording of allocate_proxy() and make_proxy_inplace() with P3401R0.
  • Fixed typo in basic_facade_builder::add_convention by @ggqshr in #190.
  • Improved wording for PRO_DEF_WEAK_DISPATCH as per @Shuenhoy's feedback.
• Revised the semantics of proxy_invoke() and proxy_reflect().
• Improved pipeline infrastructure to facilitate engineering. Specifically,
  • Enabled automated benchmarking for CI builds.
  • Updated macOS image version to 15.
  • Updated Ubuntu image version to 24.04.
  • Improved release pipeline to generate a proxy-{version}.tgz package to facilitate consumption.
• Updated the value of feature test macro __msft_lib_proxy to 202410L.

New Contributors

• @ggqshr made their first contribution in #190

Full Changelog

3.0.0...3.1.0

• Fix broken link by @mingxwa in #161
• Update wording for allocate_proxy and make_proxy_inplace by @mingxwa in #163
• Fix documentation format by @mingxwa in #166
• Reduce semantics of proxy_invoke by @mingxwa in #167
• Update Ubuntu pipeline image by @mingxwa in #168
• Add benchmarks by @mingxwa in #169
• Resolve warnings in unit tests by @mingxwa in #173
• Pump library version by @mingxwa in #172
• Add assertion for proxy_invoke() and proxy_reflect() by @mingxwa in #175
• [Build] Update macOS to 15 by @mingxwa in #176
• Improve benchmarking command line by @mingxwa in #177
• Force enable EBO on MSBuild when building with clang-cl by @mingxwa in #179
• Resolve build issues for NVHPC by @mingxwa in #182
• Generate benchmarking report by @mingxwa in #181
• Stabilize benchmarking report by @mingxwa in #183
• Implement PRO_DEF_FREE_AS_MEM_DISPATCH by @mingxwa in #189
• Update add_convention.md by @ggqshr in #190
• Implement accessibility support for reflection by @mingxwa in #191
• Add pipeline for NVHPC by @mingxwa in #197
• Improve accessibility in debugging by @mingxwa in #200
• Refactor unit tests by @mingxwa in #201
• Improve accessibility in debugging for free functions by @mingxwa in #202
• Improve release pipeline by @mingxwa in #203
• Improve wording for PRO_DEF_WEAK_DISPATCH by @mingxwa in #204
• Fix release pipeline by @mingxwa in #205
• Fix NVIDIA trade name by @mingxwa in #206

3.0.0

Proxy 3.0.0 is Now Available!

Check out the new features in our announcement!

Please find more technical details with the following links:

• API Reference: https://microsoft.github.io/proxy/docs/specifications.html
• Frequently Asked Questions: https://microsoft.github.io/proxy/docs/faq.html

New Contributors

• @frederick-vs-ja made their first contribution in #59
• @alvarogalloc made their first contribution in #133

Full Changelog: 2.0.0...3.0.0

3.0.0-rc1

Proxy 3: Feature Complete

After evolving for around half a year, Proxy 3 is now feature complete, with the latest and greatest design for modern runtime polymorphism in C++. Full documentation will be available with the final release of version 3.0.0 soon. Please stay tuned.

What's Changed

• Fix helper macros for multiple signatures by @mingxwa in #96
• Fix UB in in-place construction by @mingxwa in #99
• Fix GCC pipeline by @mingxwa in #101
• Improve facade infrastructure by @mingxwa in #102
• Improve invocation APIs and facilities to define an operator dispatch by @mingxwa in #106
• Simulate overload resolution in macros by @mingxwa in #110
• Implement pointer-to-member support by @mingxwa in #111
• Refactoring: Improve code clarity by @mingxwa in #112
• Fix typo by @mingxwa in #114
• Implement indirection syntax by @mingxwa in #121
• Improve accessibility by @mingxwa in #124
• Move direction semantics from dispatches to conventions by @mingxwa in #125
• Revise semantics of proxiable_ptr_constraints by @mingxwa in #127
• Improve API design by @mingxwa in #128
• Make facade_builder a class type, rather than a type alias by @mingxwa in #129
• Improve code quality by @mingxwa in #130
• fix referencing non-existent vcpkg website by @alvarogalloc in #133
• Revise pro::facade_builder::restrict_layout by @mingxwa in #132
• Refactor implementation of meta_ptr by @mingxwa in #139
• Remove some macros by @mingxwa in #136
• Remove redundant macro ___PRO_DEF_BRACKETS_OP_ACCESSOR by @mingxwa in #144
• Remove redundant semicolon by @mingxwa in #145
• Add feature test macro by @mingxwa in #146
• Add more samples by @mingxwa in #148
• Remove vcpkg.json in samples by @mingxwa in #149
• Run BVT with AppleClang by @mingxwa in #150
• Update Google test version by @mingxwa in #151
• Fix build error by @mingxwa in #153
• Add .gitattributes by @mingxwa in #155

New Contributors

• @alvarogalloc made their first contribution in #133

Full Changelog: 2.4.0...3.0.0-rc1

2.4.0

People want proxy.Fun() syntax. Now done.

Full Changelog: 2.3.2...2.4.0