Andrew Gallagher

This commit introduces a **new capability** by adding the `allow_unsandboxed_action_cache_uploads` parameter to the `meta_internal_extra_params` dictionary for `actions.run()`. This parameter, when set to `True`, instructs **Remote Execution (RE)** workers to upload action results to the **action cache** even if the action ran without network isolation. This change primarily affects the **command execution** and **RE action creation** subsystems, specifically within `MetaInternalExtraParams` parsing and propagation. The **feature addition** enables actions that require network access but produce deterministic outputs, such as `fbpkg_fetch`, to benefit from **RE action caching**, thereby improving overall build performance and efficiency.

This commit provides a **critical bug fix** and **enhancement** to the **PAR loading mechanism** on **macOS**, specifically addressing issues when using `/dev/fd/<N>` paths. It resolves a **spawn worker hang** by extending `sitecustomize.py` to correctly handle `/dev/fd/N` paths for multiprocessing workers, preventing `FD_CLOEXEC` from invalidating resource access. Furthermore, it eliminates **shared file offset races** within the `zipimport` module by introducing a `pread()`-based replacement for `_read_directory` in `__run_par_main__.py`, ensuring robust and concurrent resource access. This significantly improves the **stability and reliability** of PAR-based applications on macOS.

This commit introduces a **feature enhancement** and **refactoring** to the **Python wheel build system**, specifically improving how ABI and Python version tags are managed. It **adds `abi` and `python` fields to the `PythonWheelToolchainInfo` provider** in `prelude/python/python_wheel_toolchain.bzl`, centralizing this critical metadata and setting the default platform to 'any'. Consequently, the `python_wheel` rule in `prelude/python/python_wheel.bzl` is **refactored to derive these tags directly from the toolchain**, rather than relying on direct attributes, and removes support for future Python version metadata. This change ensures **proper and consistent `abi` and `python` tags for `manylinux` wheels**, enhancing the accuracy and compatibility of generated Python packages.

This commit introduces a **new `python_wheel_toolchain` mechanism** to provide configurable tools for building Python wheels. It defines the `PythonWheelToolchainInfo` provider in `prelude/python/python_wheel_toolchain.bzl`, allowing users to specify custom build and repair tools. The new toolchain is registered in `toolchains_common.bzl` and integrated into the `python_wheel` rule in `prelude/python/python_wheel.bzl` via a new attribute. This **new feature** significantly enhances the flexibility and customization options for the **Python wheel build process**.

This commit introduces a **new capability** to specify the `platform` for Python wheels by leveraging the `python_wheel_toolchain`. Specifically, the `PythonWheelToolchainInfo` provider in `prelude/python/python_wheel_toolchain.bzl` now includes a `platform` field, allowing a default platform tag to be defined at the toolchain level. The **`python_wheel` rule** in `prelude/python/python_wheel.bzl` is updated to resolve this platform tag from the toolchain if it's not explicitly set on the wheel target, and the `_whl_cmd` is adjusted accordingly. This enhancement provides a more centralized and consistent way to manage platform tags for generated Python wheels.

This commit introduces a **new feature** to the **C++ build system**, enabling **dependent-specific linkage** for `prebuilt_cxx_library` dependencies. It exposes `prefer-shared` and `prefer-static` sub-targets within the `prebuilt_cxx_library` rule, allowing consumers to explicitly request a preferred linkage type. This enhancement, implemented by **refactoring** the `prebuilt_cxx_library_impl` function in `prelude/cxx/cxx.bzl` to use helper functions like `_create_prebuilt_library_outputs`, provides greater control over direct dependencies. Notably, this preferred linkage choice **does not propagate to transitive dependencies**.

This commit introduces a **new capability** to the **C++ build system** by adding `prefer-shared` and `prefer-static` sub-targets to the `cxx_library` rule. This enhancement allows for **dependent-specific linkage control** of direct `cxx_library` dependencies, providing greater flexibility in how C++ libraries are consumed. The change is implemented within the `cxx_library_parameterized` function in `prelude/cxx/cxx_library.bzl`. It's important to note that this preferred linkage setting applies only to immediate dependencies and does not propagate to transitive dependencies.

This commit **enables `liburing` support by default** for **Linux builds** within the **`folly/io/async`** module. This **configuration change** leverages `io_uring` to provide **better I/O performance** on compatible kernels. The build configuration file `folly/io/async/BUCK` is updated to activate this feature, including specific overrides for certain Linux environments. Consequently, applications utilizing **`folly/io/async`** on Linux will automatically benefit from these performance enhancements where `io_uring` is available.

This commit provides a **bug fix** to the **command executor configuration** logic within `prelude/tests/re_utils.bzl`. It **corrects the evaluation of configuration properties** in the `get_re_executors_from_props` function. Previously, the `local_listing_enabled` flag was erroneously ignored if `listing_capabilities` was not also present, leading to incorrect executor setup. This change ensures that **local listing functionality** is properly respected and applied, preventing unintended behavior in command execution.

This commit introduces a **new capability** to **override `resource_unit` settings specifically for listing operations** within **remote execution (RE) configurations**. Previously, `resource_unit` settings might have been applied uniformly, but this change enables more granular control over resource allocation for specific remote execution tasks. The update, primarily reflected in the `prelude/tests/re_utils.bzl` test file and related to the `get_re_executors_from_props` symbol, ensures that resource allocation for listing can be independently configured. This enhancement provides greater flexibility in managing resources for different types of remote execution tasks.

This commit implements a **build system fix** to resolve issues with untracked access to `fbsource` paths, particularly for the **NCCL feedstock**. It introduces a `custom_source_tree` rule to explicitly compose the required subset of `fbsource` and passes a rule-reference via an environment variable for proper input tracking. The `folly/BUCK` file is updated to include an `fb_native.export_file` rule named `src-tree`, which exports the current directory as a source tree reference. This change ensures that the **Buck2 build system** correctly identifies and tracks all necessary source inputs for the **NCCL feedstock**, enhancing build reliability.

This commit **corrects a linking oversight** by ensuring that `RPATH`s are properly set for **all omnibus root libraries**, including non-extension ones, within the **Python wheel build process**. Previously, `RPATH`s were only applied to extension roots, leading to issues where other omnibus roots could not find their internal dependencies like `libomnibus.so`. The change modifies the `_rpath` helper function and `_impl` in `prelude/python/python_wheel.bzl` to broaden this application. This **maintenance fix** guarantees that all components of a **Python wheel** can correctly resolve their dependencies at runtime, preventing execution failures.

This commit **fixes** a critical issue in **Python editable installs** where **native libraries** were symlinked, leading to broken `RPATH` resolution. The **Python wheel build process** (`prelude/python/python_wheel.bzl`) is updated to **copy native libraries** into the editable tree instead of symlinking them, as native code does not require in-place modification. Additionally, the `create_link_tree.py` utility is enhanced to support this new copying mechanism, ensuring `RPATH`s correctly resolve relative to the copied files. This **bug fix** prevents runtime errors and improves the reliability of development environments for projects with native extensions.

This commit **refines the C++ omnibus linking process** by specifically scoping the `--no-as-needed` linker flag. Previously, this flag was applied globally, inadvertently preventing all libraries from being dropped during linking, which was an unintended side-effect. This **bug fix** now ensures the flag is applied only to the **dummy omnibus DSO** within `prelude/cxx/omnibus.bzl`, allowing other unused libraries to be correctly optimized out. This improves linker efficiency and potentially reduces binary sizes for projects utilizing the omnibus system.

This commit **fixes a potential conflict** by assigning a unique SONAME to each `omnibus` library embedded within Python wheels. Previously, installing multiple `omnibus`-enabled wheels in the same environment could lead to conflicts due to shared `libomnibus.so` names. The change modifies the **Python wheel build logic** within `prelude/python/python_wheel.bzl` to ensure that the `create_omnibus_libraries` function generates distinct identifiers for each library. This **critical maintenance update** prevents runtime issues and improves the stability of Python environments utilizing multiple such wheels.

This commit introduces a **new capability** to the **omnibus library creation system** by allowing the SONAME to be parameterized. Specifically, the `prelude/cxx/omnibus.bzl` build file now accepts an `omnibus_lib_name` argument in functions such as `_omnibus_soname` and `create_omnibus_libraries`. This **feature enhancement** provides greater flexibility, enabling users to specify a custom name for the generated `libomnibus.so` file, rather than relying on a fixed default.

This commit introduces a **new capability** to the **Python toolchain configuration** by adding `wheel_extension_linker_flags`. This new field, defined in `PythonToolchainInfo` within `prelude/python/toolchain.bzl`, allows specifying linker flags specifically for native extensions included in Python wheels. The `prelude/python/python_wheel.bzl` module then consumes these toolchain-level flags, applying them as `extra_root_ldflags` during the build process for such extensions. This enhancement provides more granular control over the linking of native components within Python wheels, improving build flexibility and potentially resolving platform-specific linking challenges.

This commit introduces a **new capability** for **prebuilt C++ library rules**, allowing them to accept an optional `third_party_build` parameter. The `prebuilt_cxx_library_impl` function in `prelude/cxx/cxx.bzl` is updated to conditionally generate shared library information based on this new attribute. This enhancement to the `prebuilt_cxx_library` rule definition in `prelude/rules_impl.bzl` enables these rules to export custom `ThirdPartyBuildInfo`, improving the integration and representation of external dependencies within the build system. The change primarily affects the **build system's definition and implementation of prebuilt C++ libraries**, providing greater flexibility for managing third-party components.

This commit **refactors the Rust build system** to address **memory inefficiency** in how `ThirdPartyBuildInfo` is managed. Specifically, it modifies the `RustLinkInfo` structure in `prelude/rust/link_info.bzl` to store a single, consolidated `ThirdPartyBuildInfo` object, rather than a list, by utilizing `tsets` to avoid redundant data copying. This **memory optimization** impacts various **Rust link provider functions** in `prelude/rust/rust_library.bzl`, such as `_proc_macro_link_providers`, which are updated to correctly create and consume the unified object. The change aims to reduce memory consumption and improve performance during the Rust build process, especially for projects with numerous third-party dependencies.

This commit introduces a **fix** and a **tooling improvement** for the **`ThirdPartyBuildInfo` provider**. It modifies the `python_library_impl` function within `prelude/python/python_library.bzl` to clear out unnecessary default include and bin paths from the `ThirdPartyBuildInfo` manifest, ensuring more accurate build information. Additionally, a new `third-party-build` sub-target is added, providing a direct and convenient way to build and debug the `ThirdPartyBuildInfo` manifest. This change improves the correctness of build metadata and enhances developer debugging capabilities for third-party dependencies.