4.0.1

Breaking changes

• Removed WORKSPACE support
• Drop bazel 7 support
• Remove swift.vfs_overlay (use swift.use_explicit_swift_module_map instead) by @keith in #1781

New features

• Add opt-in support for explicit modules, see the docs for usage.
• Add opt-in layering check, enable with --features=swift.layering_check_swift
• Add Hermetic Swift Toolchain Support with Bzlmod Extension by @ma-oli in #1630
• Add swift.emit_localized_strings feature for compiler string extraction by @jpsim in #1776

Other notable changes

• Fix issues building on some Linux versions by @luispadron in #1633
• Dont pass -file-prefix-map with Xcode path remap on Linux by @luispadron in #1634
• remove WORKSPACE support by @aaronsky in #1613
• Cherry-pick: start refactoring the Swift build APIs to remove the C++ toolchain as a dependency of the Swift toolchain. by @luispadron in #1635
• Updates swift_argument_parser version by @csmulhern in #1636
• Add missing Swift 6.2 upcoming features for v6 mode by @luispadron in #1637
• Fix executing tests by @marekcirkos in #1639
• Update const_protocols_to_gather.json to latest by @kntkymt in #1641
• chore: update main CI for latest Bazel by @luispadron in #1644
• Update protobuf dependency version to 33.4 for Bazel 9 by @luispadron in #1647
• Refactor toolchains to avoid eagerly evaluating autoconfig repo by @dzbarsky in #1651
• Fix data propagation to underlying libs for mixed libraries by @luispadron in #1654
• Update protobuf to 34.0 for Bazel 9 by @luispadron in #1656
• Update BCR presubmit for Bazel 9 & rolling releases and drop Bazel 7 by @luispadron in #1658
• use prebuilt proto toolchain from protobuf@34.0 by @aaronsky in #1660
• Revert "Use apple constraints over config_setting_group in select (#1… by @ma-oli in #1665
• Update swift-syntax for bazel 9.x support by @keith in #1666
• fix(toolchain): preserve -target flag when sdkroot is set by @ma-oli in #1662
• Only use -Xcc -working-directory -Xcc . when emitting PCM files, not when compiling Swift code that consumes them. by @luispadron in #1663
• test(toolchain): add toolchains unit tests by @ma-oli in #1667
• Fix empty target_system_name by @thii in #1668
• Add Hermetic Swift Toolchain Support with Bzlmod Extension by @ma-oli in #1630
• Avoid emitting -LNone in developer_dirs_linkopts on Linux by @bc-lee in #1670
• Explicitly pass .swiftmodule and .swiftinterface files as action inputs by @adincebic in #1583
• Pass --incompatible_enable_proto_toolchain_resolution for BCR builds by @adincebic in #1678
• Use CC toolchain from rules_cc in tests by @adincebic in #1680
• Remove the extra coverage file support. by @keith in #1682
• Remove _cc_toolchain attr by @keith in #1681
• Add flag_aliases for swiftcopt by @keith in #1683
• Update comment for -coverage-prefix-pwd-is-canonical by @kirillyakimovich in #1646
• Make sure gazelle is up to date on CI by @keith in #1688
• chore: Remove getattr for Bazel 6 compatibility fallback in target tr… by @manojmahapatra in #1689
• Update buildifier by @keith in #1690
• Remove repo name from flag_alias for now by @keith in #1693
• Fix more bzl_library visibility by @keith in #1692
• Update some bazelrc flags by @keith in #1696
• Add linux support to tools/swift-releases by @keith in #1699
• Fix is exec config for 9.0.0 by @keith in #1698
• Improve linux failure message by @keith in #1704
• Fix argv[0] with process spawning by @keith in #1700
• Partially fix swiftly usage by @keith in #1701
• Add --check_direct_dependencies=off by @keith in #1702
• Fix new warning when building modules by @keith in #1697
• Add clang_module to precompile_clang_module return by @keith in #1707
• Add support for user.bazelrc by @keith in #1706
• Cherry pick some swiftinterface compile fixes by @keith in #1705
• Fix missing bzl_library dep by @keith in #1708
• Remove old docs symbols by @keith in #1709
• Extract swift version on linux by @keith in #1710
• Improve docs setup by @keith in #1711
• Disable warnings from creating system PCMs by @keith in #1714
• Remove -disable-implicit-swift-modules by @keith in #1713
• Pass additional_swiftc_copts to PCM compiles by @keith in #1715
• Embed PCM paths in swiftmodules for explicit modules by @keith in #1716
• Disable clang warning about relocated PCMs by @keith in #1717
• Pass --target through -Xcc by @keith in #1718
• Skip clangModuleMapPath for system modules by @keith in #1684
• Add test/transitions.bzl by @keith in #1720
• Add action config for swiftinterface to swift_toolchain by @keith in #1722
• Add explicit module support by @keith in #1687
• Add clang-format pre-commit hook by @keith in #1724
• Add arm64e to scanner by @keith in #1726
• Add swift_verify_test rule by @keith in #1727
• Add explicit module app extension test by @keith in #1728
• Parallelize more scanning by @keith in #1729
• Remove old pcm_file API by @keith in #1723
• drop bazel 7 support by @aaronsky in #1730
• Use all_compile_action_names when possible by @keith in #1725
• Fix clang-format by @keith in #1734
• Add more SwiftInfo to system_module_group by @keith in #1732
• Add verify test for add_default_precompiled_modules by @keith in #1731
• Add separate sdk toolchain type by @keith in #1733
• Parse /usr/include/module.modulemap for explicit modules by @keith in #1735
• Add cross import overlay handling by @keith in #1737
• Remove XCTest specific linker flags by @keith in #1740
• Add error for objc pcm with explicit modules by @keith in #1739
• Handle cross import overlays from transitive deps by @keith in #1742
• Fix linking cross module overlays without use_explicit_swift_module_map by @keith in #1743
• Remove absolute path to Xcode from rpaths by @keith in #1741
• Don't drop -target from swiftinterface files by @keith in #1746
• Use developer dir symlink for swiftinterfaces by @keith in #1747
• Update pre-commit hooks by @keith in #1748
• Handle -v in the worker by @keith in #1750
• Remove duplicated variables in proto code by @keith in #1752
• Fix test observer warnings-as-errors build by @AttilaTheFun in #1754
• docs: add standalone Swift toolchain guide by @ma-oli in #1755
• Cleanup argument parser label by @keith in #1756
• Add -prefix-serialized-debugging-options by @keith in #1757
• Always enable -no-clang-module-breadcrumbs by @keith in #1758
• Fix the test observer's handling of suites in more recent version of swift-testing. by @keith in #1760
• Factor out the computation of the entry point name for binary rules into its own helper function. by @keith in #1763
• Stop using -Xfrontend for -module-alias. by @keith in #1765
• Add the ability to ban compiler flags by prefix. by @keith in #1769
• Move the C++ toolchain into its own execution group by @keith in #1759
• Unconditionally add the testing macro plugin subdirectory to compile actions. by @keith in #1772
• Only disable parse_headers when calling cc_common.compile on a set of headers that include the Swift generated header. by @keith in #1773
• Remove supports Swift 6 feature by @keith in #1771
• Add a mechanism to pass through arbitrary flags to other tools that the Swift worker invokes, and apply it to the generated header rewriter. by @keith in #1774
• Unify early exit for now tests behavior by @keith in #1761
• Wording adjustments by @keith in #1762
• Make the presence of a swift_overlay imply the same thing as the auto_module hint if no other swift_interop_hint is provided. by @keith in #1766
• Add some upstream worker libs by @keith in #1775
• Add a feature_configuration argument to derive_swift_module_name. by @keith in #1764
• Add direct_swift_infos to SwiftInteropInfo by @keith in #1767
• Allow a target using create_swift_interop_info to supply a different compilation context for Swift module map generation than the one that it propagates in its CcInfo. by @keith in #1770
• Clean up some features that are no longer needed. by @keith in #1778
• Remove logic that re-exports specific dependency attributes from swift_clang_module_aspect that is no longer used. by @keith in #1777
• Add swift.emit_localized_strings feature for compiler string extraction by @jpsim in #1776
• Refactor argument parsing in worker by @keith in #1779
• Implement swift layering check by @keith in #1780
• Remove swift.vfs_overlay by @keith in #1781
• Pass job_env through to hermetic pcm logic by @keith in #1784
• Add docs on explicit modules precompiled frameworks by @keith in #1786
• Use -swift-module-file for explicit modules by @keith in #1787
• Fix symlinks to developer dir by @keith in #1791
• Revert "Use -swift-module-file for explicit modules (#1787)" by @keith in #1789
• Update explicit module docs by @keith in #1795
• Add GitHub actions job for Xcode 26.4 tests by @keith in #1790
• Use new GA workflow for releases by @keith in #1797
• Remove unused configurator by @keith in #1792
• Pass -disallow-implicit-swift-modules with explicit modules + deps by @keith in #1788
• Only pass system pcms through explicit json file by @keith in #1794
• Remove -fmodule-file when using explicit json file by @keith in #1799
• Stop using repo_name by @adincebic in #1753
• Fix linux host with explicit modules by @keith in #1800
• Fix BareSlashRegexLiterals warning by @keith in #1801
• Update lldb explicit module docs by @keith in #1802
• Propagate testonly to mixed language headers by @brentleyjones in #1803
• Scope -clang-target to explicit modules by @keith in #1804
• Add docs to bcr releases by @keith in #1805
• Fix swift_overlay using wrong features variable by @keith in #1806
• Create ready for review PR on BCR by @adincebic in #1808
• Mark explicit modules module extension as reproducible by @keith in #1810
• Allow suppression aspect hints to override rules by @keith in #1811
• Remove test specific bzl_library targets by @keith in #1812
• Add top level example by @keith in #1814
• use a perl script for mixed_language_module_map_extender by @alex-ameen in #1624
• Add swift_binary(linkshared = True) for shared libraries by @AttilaTheFun in #1820
• Add shared framework for Swift SDK cross-compilation toolchains by @AttilaTheFun in #1821
• Move developer dir remapping to features by @keith in #1825
• Format embedded BUILD tpl by @keith in #1823
• Support cross-compiling to Android with a Swift SDK by @AttilaTheFun in #1818
• Remove file_prefix_map disable from embedded setup by @keith in #1824
• Ignore examples for bzl_library generation by @keith in #1826
• Build and test Swift natively on a Windows host by @AttilaTheFun in #1819
• Support cross-compiling to WebAssembly with a Swift SDK by @AttilaTheFun in #1817
• Link libdispatch for Swift Concurrency on Android by @AttilaTheFun in #1830
• Correctly forward external_include_paths to swift compiler by @DoDoENT in #1829
• Rename toolchain template BUILD file by @keith in #1836
• Remove unnecessary renaming in load statements by @keith in #1832
• Remove for_bazel_tests by @keith in #1831
• Remove @mattrobmattrob from CODEOWNERS by @mattrobmattrob in #1837
• Update bazel_features by @keith in #1838
• Remove depsets from many linkopts uses by @keith in #1839
• Move non_module_deps into MODULE.bazel by @keith in #1846
• Remove swift fragment conditional by @keith in #1848
• Stop using bazel_features for extension_metadata by @keith in #1841
• Move xcode_swift_toolchain out of local repo by @keith in #1845
• Export bzl file for docs by @keith in #1844
• Remove explicit apple_support use_extension by @keith in #1840
• Move swift shas to json files by @keith in #1834
• Update Swift release metadata by @github-actions[bot] in #1849
• Cancel github actions test jobs on the same PR by @keith in #1847
• Expand target list on CI by @keith in #1843
• Add rules_python flags for remote exec by @keith in #1854
• Move wasm templating to separate BUILD file by @keith in #1835
• Fix missing runfiles for proto rules by @keith in #1855
• Fix WMO num-threads detection by @qyang-nj in #1856
• Fix incorrect triple for Android by @keith in #1859
• Remove -objc_abi_version linker flag by @keith in #1862
• Remove Xcode rpaths for non macOS binaries by @keith in #1864
• Improve hermetic toolchain support, add static stdlib support by @keith in #1853
• Fix pre-commit formatting by @keith in #1868
• Fix -verify with remote exec by @keith in #1867
• Use HEAD rules_android for CI by @keith in #1869
• Remove toolchain_name from sdk module extensions by @keith in #1833
• Move android templating to separate BUILD file by @keith in #1863
• Scope linkopts logic to wasm by @keith in #1865
• Fix multiple archive_overrides by @keith in #1871
• Fix symbolgraph extraction with explicit modules by @keith in #1870
• Add missing repo name to docs by @keith in #1872
• fix(mixed_language_library): Include own source files in code coverage file info by @amorde in #1874
• Fix spaces in defines by @keith in #1877
• Add a test for mixed_language_coverage instrumented files by @keith in #1875
• Don't generate macOS target toolchain from hermetic toolchains by @keith in #1876
• Gate the direct SwiftInfo pass-throughs on the layering features by @mauriciogg in #1879
• Move dev dependencies into MODULE.bazel by @keith in #1882
• Delete unused worker proto by @keith in #1883
• Update include to avoid musl warning by @keith in #1888
• Fix an error from -Wsign-compare by @Yannic in #1889
• Add more known bad modules for Xcode 27 by @keith in #1890
• Add opt-in direct compiler plugin loading by @markvasiv in #1891
• Add -disable-sandbox to module interface action by @keith in #1892
• Add target label to layering check violation message by @adincebic in #1893
• Export Swift binary from standalone toolchain by @adincebic in #1896
• Stop emitting .swiftsourceinfo if not explicitly requested by @adincebic in #1895

New Contributors

• @marekcirkos made their first contribution in #1639
• @bc-lee made their first contribution in #1670
• @manojmahapatra made their first contribution in #1689
• @alex-ameen made their first contribution in #1624
• @DoDoENT made their first contribution in #1829
• @amorde made their first contribution in #1874
• @mauriciogg made their first contribution in #1879
• @Yannic made their first contribution in #1889
• @markvasiv made their first contribution in #1891

Full Changelog: 3.6.1...4.0.1

This release is compatible with Bazel 8.x LTS, 9.x LTS, and rolling releases.

MODULE.bazel Snippet

bazel_dep(name = "rules_swift", version = "4.0.1")