Ian Childs

This commit performs a significant **refactoring** of the **Java build rules** by consolidating `extra_attributes` directly into their respective rule declarations within `java_rules.bzl`. This change **simplifies `java.bzl`** to only export `implemented_rules` and removes the `extra_attributes` dictionary entirely, with `rules_impl.bzl` updated to reflect this. Additionally, `AbiGenerationMode` and `dex_min_sdk_version` are **relocated** from `java.bzl` to `java_rules.bzl`, necessitating updates to import paths in `android_rules.bzl` and `kotlin_rules.bzl`. The overall goal is to improve **code organization and clarity** within the build system without altering functional behavior.

This commit **refactors** the definition of extra attributes for **Kotlin build rules** by moving them directly into their respective rule declarations. Specifically, `extra_attributes` previously defined in `kotlin.bzl` are now integrated into the `kotlin_library` and `kotlin_test` rule definitions within `kotlin_rules.bzl`, including private toolchain attributes and validation dependencies. This change **simplifies** `kotlin.bzl` by removing the `extra_attributes` dictionary entirely and updates `rules_impl.bzl` to pass an empty dictionary for Kotlin's extra attributes, making the rule definitions more explicit and self-contained.

This commit performs **maintenance cleanup** by **removing the `-no-reflect` flag** from the **Kotlin compiler configuration**. This flag was a no-op because it was a modifier for `-include-runtime`, which was previously removed as it only applied when `kotlinc` output to a JAR, not a directory. The change **simplifies the build system** by eliminating dead code and updates comments to reflect why both flags are omitted. This **refactoring** has no impact on the compilation behavior or the resulting output, serving purely as a **cleanup** of unused build options.

This commit performs a significant **refactoring** of the **Android build system's rule definitions** by moving `extra_attributes` directly into their corresponding rule declarations within `android_rules.bzl`. This change centralizes attribute definitions, simplifying `android.bzl` by removing the `extra_attributes` dictionary entirely and updating `rules_impl.bzl` to pass an empty dictionary for Android extra attributes. The **refactoring** ensures that all rule-specific attributes, including transition dependency overrides and private toolchain attributes, are defined alongside their rules. Consequently, external files such as `apex.bzl`, `host_rules.bzl`, and `kmp_library.bzl` are updated to import symbols directly from `android_rules.bzl`, streamlining the overall build configuration.

This commit performs a widespread **refactoring** across the **Buck2 build system**, explicitly setting `has_content_based_path = False` in all existing calls to `actions.declare_output` within the `fbcode/buck2` codebase. This change affects numerous **build rules and test definitions** found in modules like `app/buck2_external_cells_bundled`, `prelude/rust`, and various `tests/core` directories. While semantically a **no-op** for current build behavior, as `False` is already the default, it is a critical **preparatory step** to ensure future compatibility. This explicit annotation pins existing call sites to their current behavior before the default value of `has_content_based_path` is changed to `True`, preventing unintended changes in output path generation.

This commit **relands a previous change** to ensure that **KotlinCD** (Kotlin Continuous Delivery) consistently uses **content-based paths**. It **fixes an issue** from an earlier attempt by specifically modifying the `_kotlincd_content_based_paths` function within `prelude/decls/jvm_common.bzl`. The `uses_content_based_paths_for_kotlincd` attribute is now explicitly set to `True` by default, guaranteeing that all KotlinCD-related builds leverage content-based path resolution. This **maintenance and bug fix** prevents previous erroneous modifications from impacting the build system's stability.

This commit introduces a **new capability** to accurately track files that skipped compilation during **KotlinCD incremental builds**, addressing cross-platform inconsistencies. It replaces unreliable timestamp-based checks with **content-based hashing (SHA256)** to determine if a file's content truly changed, particularly resolving issues on Linux where `std::fs::copy` does not preserve modification times. The **KotlinCD build system** is enhanced with a new `.buckconfig` flag `kotlin.track_files_which_skipped_compilation` and exposes new subtargets like `files_which_skipped_compilation` on `kotlin_library` targets to report these files. This **bug fix** provides a robust mechanism for verifying incremental compilation behavior and **fixes existing test failures** in `test_jvm_incremental.py` by allowing it to use this new, reliable tracking.

This commit performs a significant **refactoring** of **Android build rule attribute definitions** by merging `ANDROID_BINARY_BUNDLE_COMMON_EXTRA_ATTRS` from `android.bzl` into `ANDROID_BINARY_BUNDLE_COMMON_ATTRS` in `android_rules.bzl`. This consolidation eliminates a split between two files, standardizing attribute definitions by using transition dependencies for common keys and introducing new attributes such as `min_sdk_version` and `package_validators`. The change also updates `wa_android_superpack_libs` in `superpack_rule.bzl` to explicitly declare its required attributes, enhancing clarity and reducing implicit dependencies across **Android build configurations**.

This commit **refactors the Android build rule attribute definitions** by consolidating `ANDROID_BINARY_EXTRA_ATTRS` and `ANDROID_BUNDLE_EXTRA_ATTRS` directly into `ANDROID_BINARY_ATTRS` and `ANDROID_BUNDLE_ATTRS` within `prelude/decls/android_rules.bzl`. This **streamlines the configuration of `android_binary` and `android_bundle` rules** by integrating specific attributes like `strip_libraries` (now using `DISABLE_STRIPPING`), `constraint_overrides.attributes`, and `use_derived_apk` into their main attribute sets. As part of this **maintenance effort**, the `DISABLE_STRIPPING` constant is also moved, and the now-unused `_EXTRA_ATTRS` constants and `constraint_overrides` import are removed from `prelude/android/android.bzl`. This change centralizes and simplifies the attribute definitions for the **Android build system**, making the configuration more cohesive.

This commit performs a **refactoring** to **unify the `AbiGenerationMode` enum definition** within the `prelude` system, standardizing its values and centralizing it in `common.bzl`. This change eliminates a duplicate enum definition previously found in `java.bzl` and removes the need for `abi_generation_mode` attribute overrides in various **Android, Java, and Kotlin build rules**. Specifically, rules like `android_aar`, `android_library`, `java_test`, and `kotlin_library` now consistently rely on `jvm_common.abi_generation_mode()`. The overall impact is improved code consistency and reduced redundancy in the **ABI generation configuration**, making the build system more maintainable.

This commit introduces a **new capability** to the **CXX build system** by adding an `expect_eligible_for_dedupe` boolean attribute to `cxx_library` targets. This attribute, when set to `True`, ensures that associated **`cxx_compile` actions** enforce content-based paths for outputs and verify input eligibility for deduplication, preventing critical Remote Execution (RE) capacity issues. The change modifies the `cxx_library` rule definition in `prelude/decls/cxx_rules.bzl` and `prelude/decls/cxx_common.bzl`, and integrates the attribute into CXX compile command generation via `prelude/cxx/cxx.bzl`, `prelude/cxx/cxx_types.bzl`, `prelude/cxx/compile.bzl`, and `prelude/cxx/compile_types.bzl`. This **maintenance** effort aims to improve build system reliability and efficiency, with a new dedicated test target ensuring `cxx_compile` actions remain eligible for deduplication.

This commit performs a **refactoring** of the **Buck2 installation protobuf definitions** by **removing the `files` map field** from the `InstallInfoRequest` message. The field number for `files` is now reserved to prevent accidental reuse, and associated comments have been updated in both `app/buck2_install_proto/install.proto` and `prelude/toolchains/android/src/com/facebook/buck/installer/proto/install.proto`. This change streamlines the `InstallInfoRequest` structure, ensuring that the **Buck2 installation process** exclusively uses the `file_names` repeated field for specifying files, thereby simplifying the underlying data model and improving consistency.

This commit performs a **refactoring** of the **Android installer service** by removing a legacy fallback mechanism for file name retrieval. Specifically, the `handleInstallRequest` method in `InstallerService.java` no longer attempts to retrieve file names from a `filesMap`. Instead, it now exclusively relies on the `fileNamesList` provided in the `InstallInfoRequest`, as Buck2 is guaranteed to always send this information. This change **simplifies the install client logic**, standardizing file name retrieval and improving code maintainability by removing obsolete code paths.

This commit performs **documentation cleanup** by removing the `default_host_platform` attribute from the **Buck2 alias documentation**. This attribute is being deprecated and removed from all Buck2 rules because it was never actually used, making its documentation entry obsolete. The change ensures the **Buck2 build system's** documentation accurately reflects the current state of alias functionality, preventing user confusion and improving overall documentation quality.

This commit performs a significant **refactoring** and **code cleanup** across the **Buck2 build system's core rule definitions**. It systematically removes the `default_host_platform` attribute from virtually all **prelude rule declarations**, including those for Apple, C++, Android, Java, Python, Haskell, Go, OCaml, Lua, JS, Kotlin, Dotnet, Shell, Rust, and Git rules, as well as helper functions like in `apple/apple_common.bzl` and `ocaml/attrs.bzl`. This attribute was identified as unused boilerplate, meaning its removal streamlines rule definitions and improves the maintainability and clarity of the **build system's configuration files** without introducing any functional changes or downstream impact on build behavior.

This commit performs a **cleanup** by **removing the `ndk_library` rule** from the **Buck2 build system's Android prelude** and the `fb_native` wrapper. This **maintenance** task involves deleting the rule's definition from `prelude/decls/android_rules.bzl`, removing its wrapper from `fb_native_wrapper.bzl`, and updating documentation in `prelude/decls/android_common.bzl`. The `ndk_library` rule, previously used for Android NDK builds, is no longer necessary as it has no remaining callers. This change streamlines the **Android build configuration** by eliminating unused and deprecated functionality.

This commit performs **maintenance cleanup** by **removing** the unused `android_platform` rule definition from the **Buck2 prelude**. The rule, previously defined in `fbcode/buck2/prelude/decls/android_rules.bzl`, had no active callers and was never integrated into `fb_native_wrapper.bzl`. This ensures that its removal has no functional impact, streamlining the prelude by eliminating dead code.

This commit performs **dead code removal** by eliminating the **`supermodule_target_graph` rule** from the **`fb_native`** and **`buck2`** build systems. The rule's definition and export were removed from `prelude/decls/android_rules.bzl`, where a related `OnDuplicateEntry` import was also cleaned up. Its assignment was removed from `fb_native_wrapper.bzl`, and all remaining references were purged from `constants.bzl` and `parser_constants.py`. This **maintenance** task streamlines the build system by removing an unused and obsolete component, simplifying the codebase.

This commit performs **code cleanup** by removing the unused `field_ref_count_buffer_space` and `method_ref_count_buffer_space` attributes. These attributes were declared within **Buck2's Android build rules**, specifically in `android_rules.bzl` and referenced in `android_binary_for_automation` rules, but were not actively utilized by the build system. This **maintenance** task ensures that the codebase is leaner and more maintainable by eliminating dead code from the `android_binary` prelude. The change has no functional impact on builds, as the attributes were already inert, improving overall code clarity.

This commit performs **code cleanup** by **removing the unused `dex_group_lib_limit` attribute** from the **Buck2 Android build rules**. The attribute was declared in `fbcode/buck2/prelude/decls/android_rules.bzl` within the `android_binary` prelude but was never actually utilized by the build system. This **maintenance** task simplifies the codebase by eliminating dead code from `tools/build_defs/android/android_binary_for_automation/core_build_rules.bzl` and `selectified_build_rules.bzl`, with **no functional impact** on builds or developer workflows.