[build] Update to Bazel 9

.bazelrc

@@ -12,15 +12,11 @@ build --test_size_filters=-enormous
 # corresponds to small,medium,large,enormous tests (medium is default)
 build --test_timeout=3,15,60,240
 
-# As part of starlarkification, Bazel 8 removes a number of rules which now need to be imported from
-# other repositories. In the long term, load() statements will be needed to import these rules. For
-# now, we can still autoload the affected repositories when needed. Do this only for a remaining
-# protobuf components instead of the larger default autoload set – perfetto isn't importing all
-# required rules yet, but we don't want to accidentally rely on autoloading more dependencies.
-common --incompatible_autoload_externally="+ProtoInfo"
-
-# Bazel 9 forward compatibility: Disable native repo rules.
-build --incompatible_disable_native_repo_rules
+# As part of starlarkification, Bazel 8 and 9 remove a number of rules which now need to be imported
+# from other repositories. In the long term, load() statements will be needed to import these rules.
+# For now, we can still autoload the affected repositories when needed. Do this only for a remaining
+# protobuf components and rules_cc (needed with Bazel 9).
+common --incompatible_autoload_externally="+ProtoInfo,+cc_binary,+cc_import,+cc_library,+cc_shared_library,+cc_test,+cc_toolchain"
 
 # bazel7 enables Build without the Bytes (BwoB) by default. This significantly speeds up builds
 # using the remote cache since less data needs to be fetched.
@@ -34,16 +30,20 @@ import %workspace%/build/ci.bazelrc
 import %workspace%/build/rust_lint.bazelrc
 import %workspace%/build/tools/clang_tidy/clang_tidy.bazelrc
 
-# Prevents bazel cache invalidation when switching terminals
-build --incompatible_strict_action_env
-
-# Use compat repo mapping to avoid O(n^2) repo mapping size, speeding up bazel repo mapping phase
-# and conserving space
-build --incompatible_compact_repo_mapping_manifest
-
 # Continue building locally when remote cache entries fail to materialize
 build --incompatible_remote_local_fallback_for_remote_cache
 
+# TODO(soon): Flipped by default in Bazel 9, add required variables to --repo_env and enable
+build --noincompatible_repo_env_ignores_action_env
+
+# Use -isystem for cc_library includes attribute – this prevents warnings for misbehaving external
+# code.
+build:linux --features=external_include_paths --host_features=external_include_paths
+
+# Forward compatibility with future Bazel versions:
+# Disable deprecated cfg = "host" Bazel rule setting. Blocked on perfetto.
+# common --incompatible_disable_starlark_host_transitions
+
 # Our dependencies (ICU, zlib, etc.) produce a lot of these warnings, so we disable them.
 build --per_file_copt='external@-Wno-error'
 build --per_file_copt='external@-Wno-suggest-override'
@@ -473,7 +473,6 @@ coverage --config=wpt-test
 coverage --test_size_filters=-enormous
 coverage --test_timeout=240,240,240,240
 coverage --build_tests_only
-coverage --combined_report=lcov
 
 # This config is defined internally and enabled on many machines.
 # Defining it as empty just so these machines can run build commands from the workerd repo

.bazelversion

@@ -1 +1 @@
-8.5.1
+9.0.0

build/cc_ast_dump.bzl

@@ -30,7 +30,9 @@ def _cc_ast_dump_impl(ctx):
         user_compile_flags = ["-Wno-unused-command-line-argument", "-Xclang", "-ast-dump=json", "-fsyntax-only"] + ctx.fragments.cpp.copts + ctx.fragments.cpp.cxxopts,
         include_directories = cc_info.compilation_context.includes,
         quote_include_directories = cc_info.compilation_context.quote_includes,
-        system_include_directories = cc_info.compilation_context.system_includes,
+        # we need to pass external_includes, but there is no equivalent parameter in
+        # create_compile_variables – pass alongside system_includes.
+        system_include_directories = depset(transitive = [cc_info.compilation_context.system_includes, cc_info.compilation_context.external_includes]),
         framework_include_directories = cc_info.compilation_context.framework_includes,
         preprocessor_defines = cc_info.compilation_context.defines,
     )

build/deps/build_deps.jsonc

@@ -41,11 +41,6 @@
       "name": "rules_cc",
       "type": "bazel_dep"
     },
-    // Rust
-    {
-      "name": "rules_rust",
-      "type": "bazel_dep"
-    },
     // Node.js
     {
       "name": "aspect_rules_esbuild",

build/deps/gen/build_deps.MODULE.bazel

@@ -119,8 +119,5 @@ bazel_dep(name = "rules_oci", version = "2.2.7")
 # rules_python
 bazel_dep(name = "rules_python", version = "1.8.0")
 
-# rules_rust
-bazel_dep(name = "rules_rust", version = "0.68.1")
-
 # rules_shell
 bazel_dep(name = "rules_shell", version = "0.6.1")

build/deps/rust.MODULE.bazel

@@ -10,6 +10,20 @@ RUST_TARGET_TRIPLES = [
     "aarch64-unknown-linux-gnu",
 ]
 
+# rules_rust
+bazel_dep(name = "rules_rust", version = "0.68.1")
+
+# Under Bazel 9, Rust coverage is broken when using experimental_split_coverage_postprocessing.
+# TODO(cleanup): https://github.com/bazelbuild/rules_rust/pull/3812 should fix this, we're using
+# that commit for now. Switch back to regular release once resolved.
+archive_override(
+    module_name = "rules_rust",
+    integrity = "sha256-dtn87CNPspDl5xEfAGEl0eQ4HBf07vpxIdMNPRHqMqM=",
+    strip_prefix = "bazelbuild-rules_rust-cb9d412",
+    type = "tgz",
+    url = "https://github.com/bazelbuild/rules_rust/tarball/cb9d412afdb95578bd533b60483eecb373119c36",
+)
+
 rust = use_extension("@rules_rust//rust:extensions.bzl", "rust")
 rust.toolchain(
     allocator_library = "@rules_rust//ffi/rs:empty",

build/tools/clang_tidy/clang_tidy.bzl

@@ -57,6 +57,7 @@ def _clang_tidy_aspect_impl(target, ctx):
     includes = compilation_context.includes.to_list()
     quote_includes = compilation_context.quote_includes.to_list()
     system_includes = compilation_context.system_includes.to_list()
+    external_includes = compilation_context.external_includes.to_list()
     headers = compilation_context.headers
 
     # disable clang tidy if no-clang-tidy tag is defined.
@@ -84,6 +85,10 @@ def _clang_tidy_aspect_impl(target, ctx):
             quote_includes,
             transitive = [dep.quote_includes for dep in deps],
         )
+        external_includes = depset(
+            external_includes,
+            transitive = [dep.external_includes for dep in deps],
+        )
         headers = depset(
             headers.to_list(),
             transitive = [dep.headers for dep in deps],
@@ -130,6 +135,7 @@ def _clang_tidy_aspect_impl(target, ctx):
         args.add_all(includes, before_each = "-I")
         args.add_all(quote_includes, before_each = "-iquote")
         args.add_all(system_includes, before_each = "-isystem")
+        args.add_all(external_includes, before_each = "-isystem")
 
         args.add_all(toolchain_flags)
 

compile_flags.txt

@@ -2,7 +2,7 @@
 -stdlib=libc++
 -xc++
 -nostdinc
--Ibazel-bin/external/+_repo_rules+com_cloudflare_lol_html/_virtual_includes/lolhtml
+-Ibazel-bin/external/+new_local_repository+com_cloudflare_lol_html/_virtual_includes/lolhtml
 -Ibazel-bin/external/perfetto+/
 -Iexternal/ada-url+/
 -Iexternal/abseil-cpp+/
@@ -46,7 +46,7 @@
 -isystemexternal/+_repo_rules2+v8/include/cppgc
 -isystembazel-bin/src
 -isystemexternal/brotli+/c/include
--isystemexternal/+_repo_rules3+com_googlesource_chromium_icu/source/common
+-isystembazel-bin/external/+git_repository+com_googlesource_chromium_icu/_virtual_includes/icu/third_party/icu/source/common
 -isystemexternal/zlib+
 -isystembazel-bin/src/rust/cxx-integration/_virtual_includes/lib.rs@cxx
 -isystembazel-bin/src/rust/cxx-integration-test/_virtual_includes/lib.rs@cxx