Add support for Bzlmod

Requires fixing a case of a non-hermetic Python import in
`dict_validation_test` that breaks with Python 3.11, with which Bazel
uses `PYTHONSAFEPATH` by default.

A follow-up PR will provide the publishing setup for releases to the
Bazel Central Registry (BCR).

.bazelrc

@@ -12,10 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# rules_fuzzing is not yet compatible with Bzlmod.
-# Use the experimental version of the flag for Bazel 5 compatibility.
-common --noexperimental_enable_bzlmod
-
 # Force the use of Clang for all builds.
 build --repo_env=CC=clang
 

.bazelversion

@@ -1 +1 @@
-7.0.0
+7.0.1rc2

.github/workflows/bazel_test.yml

@@ -169,3 +169,23 @@ jobs:
       - name: Run regression tests on macOS
         run: |
           bazel test --verbose_failures --test_output=all //examples/...
+  bzlmod_examples_libfuzzer:
+    name: Bzlmod examples (libFuzzer)
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+      - name: Run regression tests on macOS
+        run: |
+          cd examples/bzlmod
+          bazel test --verbose_failures --test_output=all --@rules_fuzzing//fuzzing:cc_engine=@rules_fuzzing//fuzzing/engines:libfuzzer //...
+  bzlmod_examples_replay:
+    name: Bzlmod examples (replay)
+    runs-on: ubuntu-20.04
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+      - name: Run regression tests on macOS
+        run: |
+          cd examples/bzlmod
+          bazel test --verbose_failures --test_output=all --@rules_fuzzing//fuzzing:cc_engine=@rules_fuzzing//fuzzing/engines:replay //...

.gitignore

@@ -14,10 +14,19 @@
 
 # Bazel-generated files.
 /bazel-*
+/examples/bzlmod/bazel-*
 
 # Visual Studio Code configuration.
 /.vscode
 
 # IntelliSense configuration generated by
 # https://github.com/grailbio/bazel-compilation-database
 compile_commands.json
+
+# IntelliJ & CLion
+.clwb
+.ijwb
+
+# The Bzlmod lockfile is platform-dependent with Python and thus hard
+# to keep up-to-date in CI. It still speeds up local development.
+MODULE.bazel.lock

MODULE.bazel

@@ -0,0 +1,57 @@
+module(
+    name = "rules_fuzzing",
+    # Automatically updated during releases by the Publish to BCR app.
+    version = "0.0.0",
+)
+
+bazel_dep(name = "abseil-cpp", version = "20230802.1", repo_name = "com_google_absl")
+bazel_dep(name = "bazel_skylib", version = "1.5.0")
+bazel_dep(name = "platforms", version = "0.0.8")
+bazel_dep(name = "rules_python", version = "0.28.0")
+
+bazel_dep(name = "stardoc", version = "0.6.2", dev_dependency = True, repo_name = "io_bazel_stardoc")
+bazel_dep(name = "googletest", version = "1.14.0.bcr.1", dev_dependency = True, repo_name = "com_google_googletest")
+bazel_dep(name = "re2", version = "2023-11-01", dev_dependency = True)
+
+non_module_dependencies = use_extension("//fuzzing/private:extensions.bzl", "non_module_dependencies")
+use_repo(
+    non_module_dependencies,
+    "honggfuzz",
+    "rules_fuzzing_jazzer",
+    "rules_fuzzing_jazzer_api",
+    "rules_fuzzing_oss_fuzz",
+)
+
+SUPPORTED_PYTHON_VERSIONS = [
+    "3.8",
+    "3.9",
+    "3.10",
+    "3.11",
+    "3.12",
+]
+
+python = use_extension("@rules_python//python/extensions:python.bzl", "python")
+
+[
+    python.toolchain(
+        # Required to avoid an error when running as root in OSS-Fuzz.
+        ignore_root_user_error = True,
+        is_default = python_version == SUPPORTED_PYTHON_VERSIONS[-1],
+        python_version = python_version,
+    )
+    for python_version in SUPPORTED_PYTHON_VERSIONS
+]
+
+pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
+
+[
+    pip.parse(
+        extra_pip_args = ["--require-hashes"],
+        hub_name = "rules_fuzzing_py_deps",
+        python_version = python_version,
+        requirements_lock = "//fuzzing:requirements.txt",
+    )
+    for python_version in SUPPORTED_PYTHON_VERSIONS
+]
+
+use_repo(pip, fuzzing_py_deps = "rules_fuzzing_py_deps")

WORKSPACE.bzlmod

@@ -0,0 +1 @@
+# Intentionally left blank as all deps are defined in MODULE.bazel.

examples/bzlmod/.bazelrc

@@ -0,0 +1,17 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+common --repo_env=CC=clang
+common --@rules_fuzzing//fuzzing:cc_engine_instrumentation=libfuzzer
+common --@rules_fuzzing//fuzzing:cc_engine_sanitizer=asan

examples/bzlmod/BUILD.bazel

@@ -0,0 +1,13 @@
+load("@rules_fuzzing//fuzzing:cc_defs.bzl", "cc_fuzz_test")
+load("@rules_fuzzing//fuzzing:java_defs.bzl", "java_fuzz_test")
+
+cc_fuzz_test(
+    name = "cc_fuzz_test",
+    srcs = ["cc_fuzz_test.cc"],
+)
+
+java_fuzz_test(
+    name = "java_fuzz_test",
+    srcs = ["JavaFuzzTest.java"],
+    target_class = "com.example.JavaFuzzTest",
+)

examples/bzlmod/JavaFuzzTest.java

@@ -0,0 +1,23 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// A plain fuzz target that does nothing.
+
+package com.example;
+
+import com.code_intelligence.jazzer.api.FuzzedDataProvider;
+
+public class JavaFuzzTest {
+  public static void fuzzerTestOneInput(FuzzedDataProvider data) {}
+}

examples/bzlmod/MODULE.bazel

@@ -0,0 +1,5 @@
+bazel_dep(name = "rules_fuzzing")
+local_path_override(
+    module_name = "rules_fuzzing",
+    path = "../..",
+)

examples/bzlmod/cc_fuzz_test.cc

@@ -0,0 +1,22 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// A plain fuzz target that does nothing (just returns).
+
+#include <cstddef>
+#include <cstdint>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  return 0;
+}

examples/java/BUILD

@@ -16,7 +16,6 @@
 # serve as regression tests. Targets that are expected to crash or hang are
 # disabled in the OSS-Fuzz integration using the "no-oss-fuzz" tag.
 
-load("@rules_cc//cc:defs.bzl", "cc_binary")
 load("//fuzzing:java_defs.bzl", "java_fuzz_test")
 
 filegroup(

fuzzing/private/extensions.bzl

@@ -0,0 +1,22 @@
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Internal dependencies that are not Bazel modules."""
+
+load("//fuzzing:repositories.bzl", "rules_fuzzing_dependencies")
+
+def _non_module_dependencies(_):
+    rules_fuzzing_dependencies()
+
+non_module_dependencies = module_extension(_non_module_dependencies)

fuzzing/repositories.bzl

@@ -46,11 +46,11 @@ def rules_fuzzing_dependencies(oss_fuzz = True, honggfuzz = True, jazzer = True)
     maybe(
         http_archive,
         name = "bazel_skylib",
+        sha256 = "cd55a062e763b9349921f0f5db8c3933288dc8ba4f76dd9416aac68acee3cb94",
         urls = [
-            "https://github.com/bazelbuild/bazel-skylib/releases/download/1.0.3/bazel-skylib-1.0.3.tar.gz",
-            "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.0.3/bazel-skylib-1.0.3.tar.gz",
+            "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.5.0/bazel-skylib-1.5.0.tar.gz",
+            "https://github.com/bazelbuild/bazel-skylib/releases/download/1.5.0/bazel-skylib-1.5.0.tar.gz",
         ],
-        sha256 = "1c531376ac7e5a180e0237938a2536de0c54d93f5c278634818e0efc952dd56c",
     )
     maybe(
         http_archive,

fuzzing/tools/dict_validation_test.py

@@ -18,7 +18,7 @@
 """
 
 import unittest
-from dict_validation import validate_line
+from fuzzing.tools.dict_validation import validate_line
 
 
 class DictValidatorTest(unittest.TestCase):