Gerrit Code Review Rules for Bazel

Overview

These build rules are used for building Gerrit Code Review plugins with Bazel. Plugins are compiled as .jar files containing plugin code and dependencies.

Setup

The setup depends on whether the plugin uses the deprecated Bazel WORKSPACE or has already transitioned to Bazel modules.

WORKSPACE

To be able to use the Gerrit rules, you must provide bindings for the plugin API jars. The easiest way to do so is to add the following to your WORKSPACE file, which will give you default versions for Gerrit plugin API.

git_repository(
  name = "com_googlesource_gerrit_bazlets",
  remote = "https://gerrit.googlesource.com/bazlets",
  commit = "928c928345646ae958b946e9bbdb462f58dd1384",
)
load("@com_googlesource_gerrit_bazlets//:gerrit_api.bzl", "gerrit_api")
gerrit_api()

The version parameter allows to override the default API. For release version numbers, make sure to also provide artifacts' SHA1 sums via the plugin_api_sha1 and acceptance_framework_sha1 parameters:

load("@com_googlesource_gerrit_bazlets//:gerrit_api.bzl", "gerrit_api")
gerrit_api(version = "3.2.1",
           plugin_api_sha1 = "47019cf43ef7e6e8d2d5c0aeba0407d23c93699c",
           acceptance_framework_sha1 = "6252cab6d1f76202e57858fcffb428424e90b128")

If the version ends in -SNAPSHOT, the jars are consumed from the local Maven repository (~/.m2) per default assumed to be and the SHA1 sums can be omitted:

load("@com_googlesource_gerrit_bazlets//:gerrit_api.bzl", "gerrit_api")
gerrit_api(version = "3.3.0-SNAPSHOT")

MODULE.bazel

When using a Bazel module, the plugin will have to install the Gerrit API in its MODULE.bazel itself:

# The name has to be unique
module(name = "gerrit-plugin")

bazel_dep(name = "rules_jvm_external", version = "6.10")
bazel_dep(name = "com_googlesource_gerrit_bazlets")
git_override(
  module_name = "com_googlesource_gerrit_bazlets",
  remote = "https://gerrit.googlesource.com/bazlets",
  commit = "928c928345646ae958b946e9bbdb462f58dd1384",
)

GERRIT_API_VERSION = "3.12.0"

gerrit_api_version = use_repo_rule(
    "@com_googlesource_gerrit_bazlets//:gerrit_api_version.bzl",
    "gerrit_api_version"
)

gerrit_api_version(
    name = "gerrit_api_version",
    version = GERRIT_API_VERSION,
    visibility = ["//visibility:public"],
)

maven = use_extension("@rules_jvm_external//:extensions.bzl", "maven")

maven.install(
    name = "external_plugin_deps",
    artifacts = [
        "com.google.gerrit:gerrit-acceptance-framework:" + GERRIT_API_VERSION,
        "com.google.gerrit:gerrit-plugin-api:" + GERRIT_API_VERSION,
    ],
    duplicate_version_warning = "error",
    fail_if_repin_required = True,
    fail_on_missing_checksum = True,
    fetch_sources = True,
    lock_file = "//:external_plugin_deps.lock.json",
    repositories = [
        "https://repo1.maven.org/maven2",
        "https://gerrit-maven.storage.googleapis.com",
    ],
    version_conflict_policy = "pinned",
)

use_repo(maven, "external_plugin_deps")

To use a snapshot version of the Gerrit API, add the file://-URL to the list of repositories in the MODULE.bazel file and adapt the GERRIT_API_VERSION- constant, e.g.:

GERRIT_API_VERSION = "3.11.0-SNAPSHOT"

maven.install(
    name = "external_plugin_deps",
    artifacts = [
    ...
    ],
    repositories = [
        "file:///home/user/.m2/repository",
        "https://repo1.maven.org/maven2",
        "https://gerrit-maven.storage.googleapis.com",
    ],
    ...
)

<a name="basic-example"></a>
## Basic Example

Suppose you have the following directory structure for a simple plugin:

[workspace]/ ├── src │ └── main │ ├── java │ └── resources ├── BUILD └── WORKSPACE


To build this plugin, your `BUILD` can look like this:

```python
load("//tools/bzl:plugin.bzl", "gerrit_plugin")

gerrit_plugin(
    name = "reviewers",
    srcs = glob(["src/main/java/**/*.java"]),
    manifest_entries = [
        "Gerrit-PluginName: reviewers",
        "Gerrit-Module: com.googlesource.gerrit.plugins.reviewers.Module",
    ],
    resources = glob(["src/main/**/*"]),
)

Now, you can build the Gerrit plugin by running bazel build <plugin>.

For a real world example, see the reviewers plugin.

gerrit_plugin

gerrit_plugin(name, srcs, resources, deps, manifest_entries):

Implicit output target

<name>.jar: library containing built plugin jar

runtime_jars_allowlist_test

This macro helps plugins track the set of third-party runtime dependencies that would be packaged into the plugin and detect accidental dependency changes in CI.

Example usage in a plugin BUILD file:

    load(
        "@com_googlesource_gerrit_bazlets//tools:runtime_jars_allowlist.bzl",
        "runtime_jars_allowlist_test",
    )

    runtime_jars_allowlist_test(
        name = "check_oauth_third_party_runtime_jars",
        allowlist = ":oauth_third_party_runtime_jars.allowlist.txt",
        hint = ":check_oauth_third_party_runtime_jars_manifest",
        target = ":oauth__plugin",
    )

To refresh the allowlist after an expected change:

    bazelisk build //:check_oauth_third_party_runtime_jars_manifest
    cp bazel-bin/check_oauth_third_party_runtime_jars_manifest.txt \
       oauth_third_party_runtime_jars.allowlist.txt

Optional arguments:

normalize (default: True) — strip version suffixes from jar basenames.
exclude_self (default: True) — omit the target's own output jar(s).
size (default: “small”) — Bazel test size classification.

runtime_jars_overlap_test

This macro helps plugins detect accidental bundling of third-party runtime JARs that are already shipped by Gerrit. It compares the plugin‘s packaged runtime JAR list against a provided manifest (for example Gerrit’s //:release.war.jars.txt) and fails on overlap.

This check is typically meaningful only when the plugin is built inside the Gerrit source tree where Gerrit's runtime manifest exists. Standalone plugin workspaces should gate the test via target_compatible_with so it is reported as SKIPPED rather than failing.

Example usage in a plugin BUILD file:

load(
    "@com_googlesource_gerrit_bazlets//tools:runtime_jars_overlap.bzl",
    "runtime_jars_overlap_test",
)
load(
    "@com_googlesource_gerrit_bazlets//tools:in_gerrit_tree.bzl",
    "in_gerrit_tree_enabled",
)

runtime_jars_overlap_test(
    name = "no_overlap_with_gerrit",
    target = ":my_plugin__plugin",
    against = "//:release.war.jars.txt",
    hint = "Exclude overlaps via maven.install(excluded_artifacts=[...]) and re-run this test.",
    target_compatible_with = in_gerrit_tree_enabled(),
)

Optional arguments:

normalize (default: True) — strip version suffixes from jar basenames.
exclude_self (default: True) — omit the target's own output jar(s).
size (default: “small”) — Bazel test size classification.
hint (default: "") — optional guidance printed on failure.

On failure, the test prints the overlapping normalized jar IDs and exits non-zero.

Gerrit-tree-only checks

Some plugin tests and guardrails are meaningful only when the plugin is built inside the Gerrit source tree (e.g. checks that compare against //:release.war.jars.txt). Such checks should run when building in-tree, but be automatically skipped in standalone plugin workspaces.

Bazlets provides a typed Bazel build setting and helper to support this pattern.

Usage in plugin BUILD files

load(
    "@com_googlesource_gerrit_bazlets//tools:in_gerrit_tree.bzl",
    "in_gerrit_tree_enabled",
)

runtime_jars_overlap_test(
    name = "no_overlap_with_gerrit",
    against = "//:release.war.jars.txt",
    target = ":my_plugin",
    target_compatible_with = in_gerrit_tree_enabled(),
)

In the Gerrit source tree, enable these checks by setting the following in .bazelrc:

common --@com_googlesource_gerrit_bazlets//flags:in_gerrit_tree=true

Standalone plugin workspaces should not set this flag. In that case, the corresponding targets are marked incompatible and reported as SKIPPED by Bazel.