Support building //java with bzlmod

Create WORKSPACE.bzlmod. Before building with Bzlmod resulted in use of full WORKSPACE.
Some repos are still there, but the file should eventually be empty.

Add dep to rules_kotlin 1.9.0. This was the first version available on BCR. It pushed upgrade of
rules_jvm_external to 6.0 and rules_java to 6.5.2 (keep 6.0.0 on Bazel 6.3.0).

Add missing maven and other deps to MODULE.bazel

CI changes:
Disable Bazel 6.4.0 with bzlmod. rules_jvm_external 6.0 use use_repo_rule, which is not supported by Bazel 6.
Add C++ build "Bazel7 with Bzlmod" enabled.
Add Java builds with "Bazel 7 with/without Bzlmod".

Fixes: https://github.com/protocolbuffers/protobuf/issues/17176
PiperOrigin-RevId: 652773197

.github/workflows/test_bazel.yml

@@ -22,9 +22,7 @@ jobs:
         include:
           - runner: ubuntu
             bazelversion: '6.4.0'
-            bzlmod: true
-          - runner: ubuntu
-            bazelversion: '6.4.0'
+            # Not running Bazel 6 with bzlmod, because it doesn't support use_repo_rule in rules_jvm_external
             bzlmod: false
     runs-on: ${{ matrix.runner }}-latest
     name: Examples ${{ matrix.runner }} ${{ matrix.bazelversion }}${{ matrix.bzlmod && ' (bzlmod)' || '' }}

.github/workflows/test_cpp.yml

@@ -30,13 +30,22 @@ jobs:
           - targets: //pkg/... //src/... @com_google_protobuf_examples//... //third_party/utf8_range/...
 
           # Override cases with custom images
-          - config: { name: "Bazel7" }
+          - config: { name: "Bazel7", flags: --noenable_bzlmod }
+            version: Bazel7
             image: "us-docker.pkg.dev/protobuf-build/containers/common/linux/bazel:7.1.2-cf84e92285ca133b9c8104ad7b14d70e953cbb8e"
             targets: "//src/... //third_party/utf8_range/..."
+          - config: { name: "Bazel7 with Bzlmod", flags: --enable_bzlmod }
+            version: Bazel7bzlmod
+            image: "us-docker.pkg.dev/protobuf-build/containers/common/linux/bazel:7.1.2-cf84e92285ca133b9c8104ad7b14d70e953cbb8e"
+            targets: "//src/... //third_party/utf8_range/..."
+            # TODO: enable back command_line_interface_unittest after bug is fixed
+            exclude-targets: "-//src/google/protobuf/compiler:command_line_interface_unittest"
           - config: { name: "TCMalloc" }
+            version: TcMalloc
             image: "us-docker.pkg.dev/protobuf-build/containers/test/linux/tcmalloc@sha256:1c5133455481f4d1bb8afa477029604f41f1a3c46cebe4d9958cf1af95b5c87c"
             targets: "//src/... //third_party/utf8_range/..."
           - config: { name: "aarch64" }
+            version: TcMalloc
             targets: "//src/... //src/google/protobuf/compiler:protoc_aarch64_test //third_party/utf8_range/..."
             image: "us-docker.pkg.dev/protobuf-build/containers/test/linux/emulation:6.3.0-aarch64-68e662b3a56b881804dc4e9d45f949791cbc4b94"
     name: Linux ${{ matrix.config.name }}
@@ -51,8 +60,9 @@ jobs:
         with:
           image: ${{ matrix.image }}
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
-          bazel-cache: cpp_linux/${{ matrix.config.name }}
+          bazel-cache: cpp_linux/${{ matrix.version }}
           bazel: test ${{ matrix.targets }} ${{ matrix.config.flags }}
+          exclude-targets: ${{ matrix.exclude-targets }}
 
   linux-gcc:
     strategy:

.github/workflows/test_java.yml

@@ -31,6 +31,16 @@ jobs:
             version: '17'
             image: us-docker.pkg.dev/protobuf-build/containers/test/linux/java:17-1fdbb997433cb22c1e49ef75ad374a8d6bb88702
             targets: //java/... //java/internal:java_version //compatibility/...
+          - name: Bazel7
+            version: 'bazel7nobzlmod'
+            image: us-docker.pkg.dev/protobuf-build/containers/common/linux/bazel:7.1.2-cf84e92285ca133b9c8104ad7b14d70e953cbb8e
+            targets: //java/... //java/internal:java_version //compatibility/...
+            flags: --noenable_bzlmod
+          - name: Bazel7 with Bzlmod
+            version: 'bazel7bzlmod'
+            image: us-docker.pkg.dev/protobuf-build/containers/common/linux/bazel:7.1.2-cf84e92285ca133b9c8104ad7b14d70e953cbb8e
+            targets: //java/... //java/internal:java_version //compatibility/...
+            flags: --enable_bzlmod
           - name: aarch64
             version: 'aarch64'
             image: us-docker.pkg.dev/protobuf-build/containers/test/linux/emulation:aarch64-63dd26c0c7a808d92673a3e52e848189d4ab0f17
@@ -49,7 +59,7 @@ jobs:
           image: ${{ matrix.image }}
           credentials: ${{ secrets.GAR_SERVICE_ACCOUNT }}
           bazel-cache: java_linux/${{ matrix.version }}
-          bazel: test ${{ matrix.targets }} --test_env=KOKORO_JAVA_VERSION
+          bazel: test ${{ matrix.targets }} ${{ matrix.flags }} --test_env=KOKORO_JAVA_VERSION
 
 # TODO restore this test (or a better one) when gRPC has rebuilt with 26.x
   # linkage-monitor:

MODULE.bazel

@@ -18,7 +18,8 @@ bazel_dep(name = "jsoncpp", version = "1.9.5")
 bazel_dep(name = "rules_cc", version = "0.0.9")
 bazel_dep(name = "rules_fuzzing", version = "0.5.2")
 bazel_dep(name = "rules_java", version = "5.3.5")
-bazel_dep(name = "rules_jvm_external", version = "5.1")
+bazel_dep(name = "rules_jvm_external", version = "6.0")
+bazel_dep(name = "rules_kotlin", version = "1.9.0")
 bazel_dep(name = "rules_pkg", version = "0.7.0")
 bazel_dep(name = "rules_python", version = "0.28.0")
 bazel_dep(name = "rules_rust", version = "0.45.1")
@@ -72,5 +73,29 @@ crate.spec(
 crate.from_specs()
 use_repo(crate, crate_index = "crates")
 
+maven = use_extension("@rules_jvm_external//:extensions.bzl", "maven")
+maven.install(
+    artifacts = [
+        "com.google.caliper:caliper:1.0-beta-3",
+        "com.google.code.findbugs:jsr305:3.0.2",
+        "com.google.code.gson:gson:2.8.9",
+        "com.google.errorprone:error_prone_annotations:2.5.1",
+        "com.google.j2objc:j2objc-annotations:2.8",
+        "com.google.guava:guava:32.0.1-jre",
+        "com.google.guava:guava-testlib:32.0.1-jre",
+        "com.google.truth:truth:1.1.2",
+        "junit:junit:4.13.2",
+        "org.mockito:mockito-core:4.3.1",
+        "biz.aQute.bnd:biz.aQute.bndlib:6.4.0",
+        "info.picocli:picocli:4.6.3",
+    ],
+    repositories = [
+        "https://repo1.maven.org/maven2",
+        "https://repo.maven.apache.org/maven2",
+    ],
+)
+use_repo(maven, "maven")
+
 # Development dependencies
+bazel_dep(name = "googletest", version = "1.14.0", repo_name = "com_google_googletest", dev_dependency = True)
 bazel_dep(name = "rules_testing", version = "0.6.0", dev_dependency = True)

WORKSPACE

@@ -99,11 +99,11 @@ load("@rules_cc//cc:repositories.bzl", "rules_cc_dependencies")
 rules_cc_dependencies()
 
 # For `kt_jvm_library`
-load("@io_bazel_rules_kotlin//kotlin:repositories.bzl", "kotlin_repositories")
+load("@rules_kotlin//kotlin:repositories.bzl", "kotlin_repositories")
 
 kotlin_repositories()
 
-load("@io_bazel_rules_kotlin//kotlin:core.bzl", "kt_register_toolchains")
+load("@rules_kotlin//kotlin:core.bzl", "kt_register_toolchains")
 
 kt_register_toolchains()
 

WORKSPACE.bzlmod

@@ -0,0 +1,40 @@
+# This is a WORKSPACE file used by bzlmod in combination with MODULE.bazel.
+# It's used for a gradual migration and it should be empty.
+# Don't remove this file. If the file doesn't exist, bzlmod falls back to WORKSPACE file.
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+# TODO: either replace rules_ruby with a maintained version on BCR
+# or use bzlmod extensions to depend on this specific repo
+http_archive(
+    name = "rules_ruby",
+    urls = [
+      "https://github.com/protocolbuffers/rules_ruby/archive/b7f3e9756f3c45527be27bc38840d5a1ba690436.zip"
+    ],
+    strip_prefix = "rules_ruby-b7f3e9756f3c45527be27bc38840d5a1ba690436",
+    sha256 = "347927fd8de6132099fcdc58e8f7eab7bde4eb2fd424546b9cd4f1c6f8f8bad8",
+)
+
+load("@rules_ruby//ruby:defs.bzl", "ruby_runtime")
+
+ruby_runtime("system_ruby")
+
+register_toolchains("@system_ruby//:toolchain")
+
+# Follwing are just needed to run conformance tests, not really needed to support them via MODULE.bazel
+
+# For testing runtime against old gencode from a previous major version.
+http_archive(
+    name = "com_google_protobuf_v25.0",
+    strip_prefix = "protobuf-25.0",
+    url = "https://github.com/protocolbuffers/protobuf/releases/download/v25.0/protobuf-25.0.tar.gz",
+)
+
+# Needed as a dependency of @com_google_protobuf_v25.x, which was before
+# utf8_range was merged in.
+http_archive(
+    name = "utf8_range",
+    strip_prefix = "utf8_range-d863bc33e15cba6d873c878dcca9e6fe52b2f8cb",
+    url = "https://github.com/protocolbuffers/utf8_range/archive/d863bc33e15cba6d873c878dcca9e6fe52b2f8cb.zip",
+)
+

java/kotlin-lite/BUILD.bazel

@@ -1,5 +1,5 @@
-load("@io_bazel_rules_kotlin//kotlin:jvm.bzl", "kt_jvm_library")
 load("@rules_jvm_external//:kt_defs.bzl", "kt_jvm_export")
+load("@rules_kotlin//kotlin:jvm.bzl", "kt_jvm_library")
 load("@rules_pkg//pkg:mappings.bzl", "pkg_files", "strip_prefix")
 load("//:protobuf.bzl", "internal_gen_kt_protos")
 load("//:protobuf_version.bzl", "PROTOBUF_JAVA_VERSION")
@@ -50,7 +50,7 @@ kt_jvm_library(
 kt_jvm_export(
     name = "kotlin-lite_mvn",
     deploy_env = [
-        "@com_github_jetbrains_kotlin//:kotlin-stdlib",
+        "@rules_kotlin//kotlin/compiler:kotlin-stdlib",
         "//java/lite",
     ],
     maven_coordinates = "com.google.protobuf:protobuf-kotlin-lite:%s" % PROTOBUF_JAVA_VERSION,
@@ -99,9 +99,9 @@ kt_jvm_library(
         "//java/kotlin:only_for_use_in_proto_generated_code_its_generator_and_tests",
         "//java/kotlin:shared_runtime",
         "//java/lite",
-        "@com_github_jetbrains_kotlin//:kotlin-test",
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
+        "@rules_kotlin//kotlin/compiler:kotlin-test",
     ],
 )
 

java/kotlin/BUILD.bazel

@@ -1,5 +1,5 @@
-load("@io_bazel_rules_kotlin//kotlin:jvm.bzl", "kt_jvm_library")
 load("@rules_jvm_external//:kt_defs.bzl", "kt_jvm_export")
+load("@rules_kotlin//kotlin:jvm.bzl", "kt_jvm_library")
 load("@rules_pkg//pkg:mappings.bzl", "pkg_files", "strip_prefix")
 load("//:protobuf.bzl", "internal_gen_kt_protos")
 load("//:protobuf_version.bzl", "PROTOBUF_JAVA_VERSION")
@@ -53,7 +53,7 @@ kt_jvm_library(
 kt_jvm_export(
     name = "kotlin_mvn",
     deploy_env = [
-        "@com_github_jetbrains_kotlin//:kotlin-stdlib",
+        "@rules_kotlin//kotlin/compiler:kotlin-stdlib",
         "//java/core",
     ],
     maven_coordinates = "com.google.protobuf:protobuf-kotlin:%s" % PROTOBUF_JAVA_VERSION,
@@ -101,9 +101,9 @@ kt_jvm_library(
     deps = [
         ":bytestring_lib",
         "//java/lite",
-        "@com_github_jetbrains_kotlin//:kotlin-test",
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
+        "@rules_kotlin//kotlin/compiler:kotlin-test",
     ],
 )
 
@@ -136,10 +136,10 @@ kt_jvm_library(
         ":example_extensible_message_java_proto",
         ":only_for_use_in_proto_generated_code_its_generator_and_tests",
         ":shared_runtime",
-        "@com_github_jetbrains_kotlin//:kotlin-test",
         "@maven//:com_google_guava_guava_testlib",
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
+        "@rules_kotlin//kotlin/compiler:kotlin-test",
     ],
 )
 
@@ -162,9 +162,9 @@ kt_jvm_library(
         ":only_for_use_in_proto_generated_code_its_generator_and_tests",
         ":shared_runtime",
         "//java/core",
-        "@com_github_jetbrains_kotlin//:kotlin-test",
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
+        "@rules_kotlin//kotlin/compiler:kotlin-test",
     ],
 )
 

protobuf_deps.bzl

@@ -98,11 +98,27 @@ def protobuf_deps():
         )
 
     if not native.existing_rule("rules_java"):
-        http_archive(
-            name = "rules_java",
-            url = "https://github.com/bazelbuild/rules_java/releases/download/6.0.0/rules_java-6.0.0.tar.gz",
-            sha256 = "469b7f3b580b4fcf8112f4d6d0d5a4ce8e1ad5e21fee67d8e8335d5f8b3debab",
-        )
+        bazel_version = native.bazel_version or "999999.999999.999999"
+        version_parts = bazel_version.split("-")[0].split(".")
+        if len(version_parts) != 3:
+            fail("invalid Bazel version '{}': got {} dot-separated segments, want 3".format(bazel_version, len(version_parts)))
+        major_version_int = int(version_parts[0])
+        minor_version_int = int(version_parts[1])
+
+        if major_version_int < 6 or (major_version_int == 6 and minor_version_int <= 3):
+            # Works with Bazel 6.3.0, but not higher
+            http_archive(
+                name = "rules_java",
+                url = "https://github.com/bazelbuild/rules_java/releases/download/6.0.0/rules_java-6.0.0.tar.gz",
+                sha256 = "469b7f3b580b4fcf8112f4d6d0d5a4ce8e1ad5e21fee67d8e8335d5f8b3debab",
+            )
+        else:
+            # Version 6.5.2 works both with Bazel 6.4.0 and Bazel 7
+            http_archive(
+                name = "rules_java",
+                url = "https://github.com/bazelbuild/rules_java/releases/download/6.5.0/rules_java-6.5.0.tar.gz",
+                sha256 = "160d1ebf33763124766fb35316329d907ca67f733238aa47624a8e3ff3cf2ef4",
+            )
 
     # TODO: remove after toolchain types are moved to protobuf
     if not native.existing_rule("rules_proto"):
@@ -133,11 +149,12 @@ def protobuf_deps():
         )
 
     if not native.existing_rule("rules_jvm_external"):
-        _github_archive(
+        # Version 6.0 is the lowest that works with rules_kotlin 1.9.0
+        http_archive(
             name = "rules_jvm_external",
-            repo = "https://github.com/bazelbuild/rules_jvm_external",
-            commit = "906875b0d5eaaf61a8ca2c9c3835bde6f435d011",
-            sha256 = "744bd7436f63af7e9872948773b8b106016dc164acb3960b4963f86754532ee7",
+            strip_prefix = "rules_jvm_external-6.0",
+            sha256 = "85fd6bad58ac76cc3a27c8e051e4255ff9ccd8c92ba879670d195622e7c0a9b7",
+            url = "https://github.com/bazelbuild/rules_jvm_external/releases/download/6.0/rules_jvm_external-6.0.tar.gz",
         )
 
     if not native.existing_rule("rules_pkg"):
@@ -164,11 +181,12 @@ def protobuf_deps():
             url = "https://github.com/bazelbuild/apple_support/releases/download/1.12.0/apple_support.1.12.0.tar.gz",
         )
 
-    if not native.existing_rule("io_bazel_rules_kotlin"):
+    if not native.existing_rule("rules_kotlin"):
+        # Version 1.9.0 is the lowest available on BCR
         http_archive(
-            name = "io_bazel_rules_kotlin",
-            urls = ["https://github.com/bazelbuild/rules_kotlin/releases/download/v1.8.1/rules_kotlin_release.tgz"],
-            sha256 = "a630cda9fdb4f56cf2dc20a4bf873765c41cf00e9379e8d59cd07b24730f4fde",
+            name = "rules_kotlin",
+            sha256 = "5766f1e599acf551aa56f49dab9ab9108269b03c557496c54acaf41f98e2b8d6",
+            url = "https://github.com/bazelbuild/rules_kotlin/releases/download/v1.9.0/rules_kotlin-v1.9.0.tar.gz",
         )
 
     # Python Downloads