Convert to bzlmod, first steps.

First steps towards exclusively using MODULE.bazel, for now
a subset of changes already improving the state a lot.

  * Add MODULE.bazel and add dependencies already provided by
    the Bazel Central Registry.
  * Remove the above from WORKSPACE and
    dependency_support/{load,initialize}_external.bzl.
  * Add some patches, as some external dependencies used
    @rules_cc// to get cc_proto_library and cc_library, which is
    not available anymore in latest rules_cc (but provided by
    bazel itself)
  * Fallout: the compilation db currently can't be built anymore
    due to the compdb not compatible anymore with bzlmod.
    I have a plan to replace that, but not in this first CL; for
    now, it is just disabled.

Things for follow-up PRs
  * move the remaining load_exernal.bzl also to MODULE.bazel, but
    use the repo rules to fetch projects.
  * Upstream more tools we use to Bazel Central Registry; e.g.
    low hanging fruit would be to get a later version of protoc-gen-validate
    in there or add lineoise.
  * Rules python and its toolchain can probably be simplified.
  * fix compilation db.

Issues: #931

.bazelrc

@@ -1,10 +1,14 @@
-# We use bazel >= 6, but no bzlmod yet.
-common --noenable_bzlmod
+common --enable_bzlmod
 
 # Disable rules_python Starlark rules for Bazel 7+.
 # See https://github.com/bazelbuild/rules_python/issues/1069#issuecomment-1942053014.
 build --action_env=RULES_PYTHON_ENABLE_PYSTAR=0
 
+# Disable automatic generation of __init__.py files. This allows
+# namespace packages (such as `google`) to work correctly.
+# https://github.com/bazelbuild/bazel/issues/10076
+build --incompatible_default_to_explicit_init_py=true
+
 # Minimium c++ standard used.
 build --cxxopt "-std=c++20"            --host_cxxopt "-std=c++20"
 build --action_env=BAZEL_CXXOPTS=-std=c++20

.github/workflows/nightly-macos.yml

@@ -2,12 +2,13 @@
 # See also: https://github.com/marketplace/actions/bazel-action
 
 name: Nightly MacOS
-on:
-  schedule:
-    # Nightly at midnight PDT -- uses UTC, so 7am.
-    - cron:  '0 7 * * *'
-  # This lets us trigger manually from the UI.
-  workflow_dispatch:
+# Temporary, while in #1893, disable schedule
+#on:
+#  schedule:
+#    # Nightly at midnight PDT -- uses UTC, so 7am.
+#    - cron:  '0 7 * * *'
+#  # This lets us trigger manually from the UI.
+#  workflow_dispatch:
 
 jobs:
   build:

.gitignore

@@ -8,3 +8,4 @@ user.bazelrc
 .vscode
 .cache
 docs/
+MODULE.bazel.lock

MODULE.bazel

@@ -0,0 +1,53 @@
+module(
+    name = "xls",
+    repo_name = "com_google_xls",
+)
+
+# Compiler toolchain
+bazel_dep(name = "toolchains_llvm", version = "1.3.0")
+
+# Configure and register the toolchain.
+llvm = use_extension("@toolchains_llvm//toolchain/extensions:llvm.bzl", "llvm")
+llvm.toolchain(
+    llvm_version = "17.0.6",
+)
+use_repo(llvm, "llvm_toolchain")
+
+register_toolchains("@llvm_toolchain//:all")
+
+#
+bazel_dep(name = "abseil-cpp", version = "20240722.1", repo_name = "com_google_absl")
+bazel_dep(name = "abseil-py", version = "2.1.0", repo_name = "com_google_absl_py")
+bazel_dep(name = "bazel_features", version = "1.25.0")
+bazel_dep(name = "bazel_skylib", version = "1.7.1")
+bazel_dep(name = "boringssl", version = "0.20250114.0")
+bazel_dep(name = "googleapis", version = "0.0.0-20240819-fe8ba054a", repo_name = "com_google_googleapis")
+bazel_dep(name = "grpc", version = "1.69.0", repo_name = "com_github_grpc_grpc")
+bazel_dep(name = "nlohmann_json", version = "3.11.3.bcr.1")
+bazel_dep(name = "platforms", version = "0.0.11")
+bazel_dep(name = "protobuf", version = "29.3", repo_name = "com_google_protobuf")
+bazel_dep(name = "re2", version = "2024-07-02.bcr.1", repo_name = "com_googlesource_code_re2")
+bazel_dep(name = "riegeli", version = "0.0.0-20241218-3385e3c", repo_name = "com_google_riegeli")
+bazel_dep(name = "rules_license", version = "1.0.0")
+bazel_dep(name = "rules_pkg", version = "1.0.1")
+bazel_dep(name = "rules_proto", version = "7.1.0")
+bazel_dep(name = "verible", version = "0.0.3933")
+
+# Dev dependencies
+bazel_dep(name = "fuzztest", version = "20241028.0", dev_dependency = True, repo_name = "com_google_fuzztest")
+bazel_dep(name = "google_benchmark", version = "1.9.1", dev_dependency = True, repo_name = "com_google_benchmark")
+bazel_dep(name = "googletest", version = "1.15.2", dev_dependency = True, repo_name = "com_google_googletest")
+
+# Repositories we don't really depend on directly, but we need to provide
+# for other dependencies as they are using old versions that are not
+# compatible with current bazel.
+bazel_dep(name = "rules_bison", version = "0.3")
+bazel_dep(name = "rules_flex", version = "0.3")
+bazel_dep(name = "rules_java", version = "8.7.2")
+bazel_dep(name = "protoc-gen-validate", version = "1.0.4.bcr.2")
+single_version_override(
+    module_name = "protoc-gen-validate",
+    patch_strip = 1,
+    patches = ["//dependency_support:protoc-gen-validate/no-rulescc.patch"],
+    version = "1.0.4.bcr.2",
+)

WORKSPACE

@@ -12,45 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-workspace(name = "com_google_xls")
-
-# Load and configure a hermetic LLVM based C/C++ toolchain. This is done here
-# and not in load_external.bzl because it requires several sequential steps of
-# declaring archives and using things in them, which is awkward to do in .bzl
-# files because it's not allowed to use `load` inside of a function.
-load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
-
-# Released 2023-09-20, current as of 2024-06-26 (but there is already a 0.0.10rc1)
-# Needs to be loaded first, as llvm toolchain has an ancient version of this.
-http_archive(
-    name = "rules_cc",
-    urls = ["https://github.com/bazelbuild/rules_cc/releases/download/0.0.9/rules_cc-0.0.9.tar.gz"],
-    sha256 = "2037875b9a4456dce4a79d112a8ae885bbc4aad968e6587dca6e64f3a0900cdf",
-    strip_prefix = "rules_cc-0.0.9",
-)
-
-# Commit on  2024-07-19, current as of 2024-07-21.
-http_archive(
-    name = "toolchains_llvm",
-    integrity = "sha256-RVp0bZsDrelQAtxswWOLB4j8zCXQy/cSe1m3wL/E2PU=",
-    strip_prefix = "toolchains_llvm-01132cfdae7d7187a885cf79d5a3ac1ed8a02e5a",
-    url = "https://github.com/bazel-contrib/toolchains_llvm/archive/01132cfdae7d7187a885cf79d5a3ac1ed8a02e5a.tar.gz",
-)
-
-load("@toolchains_llvm//toolchain:deps.bzl", "bazel_toolchain_dependencies")
-
-bazel_toolchain_dependencies()
-
-load("@toolchains_llvm//toolchain:rules.bzl", "llvm_toolchain")
+# TODO(https://github.com/google/xls/issues/931): Everything here should go away and migrate to MODULE.bazel
 
-llvm_toolchain(
-    name = "llvm_toolchain",
-    llvm_version = "17.0.6",
-)
-
-load("@llvm_toolchain//:toolchains.bzl", "llvm_register_toolchains")
-
-llvm_register_toolchains()
+workspace(name = "com_google_xls")
 
 load("//dependency_support:load_external.bzl", "load_external_repositories")
 
@@ -75,22 +39,10 @@ python_register_toolchains(
     ignore_root_user_error = True,
 )
 
-# gRPC deps should be loaded before initializing other repos. Otherwise, various
-# errors occur during repo loading and initialization.
-load("@com_github_grpc_grpc//bazel:grpc_deps.bzl", "grpc_deps")
-
-grpc_deps()
-
 load("//dependency_support:initialize_external.bzl", "initialize_external_repositories")
 
 initialize_external_repositories()
 
 load("@xls_pip_deps//:requirements.bzl", xls_pip_install_deps = "install_deps")
 
 xls_pip_install_deps()
-
-# Loading the extra deps must be called after initialize_eternal_repositories or
-# the call to pip_parse fails.
-load("@com_github_grpc_grpc//bazel:grpc_extra_deps.bzl", "grpc_extra_deps")
-
-grpc_extra_deps()