Bazel 5: Rules_java needs to export the defs.bzl file to allow generating docs

[tjoneslo]

Description of the problem / feature request:

With Bazel 5, the rules_java have been moved to the internal to Bazel itself. This has removed access to the rules java defs.bzl file. This in turn blocks our ability to generate our internal build documentation.

Feature requests: what underlying problem are you trying to solve with this feature?

When building the documentation for our project using Stardoc, we need to include all of the dependencies. Since we use rules_java in our project we need to include those. We use the bazel-skylib with the bzl_library to collect the .bzl files to provide to the stardoc rules with the references to generate the documentation.

Using the bzl_library to collect the rules_java results in the error:

ERROR: /Users/tjoneslo/Documents/workspace/java/BUILD.bazel:87:12: no such target '@rules_java//java:defs.bzl': target 'defs.bzl' not declared in package 'java'; however, a source file of this name exists. (Perhaps add 'exports_files(["defs.bzl"])' to java/BUILD?) defined by /private/var/tmp/_bazel_tjoneslo/36945587f23d21b910d2b6901d7e1f8e/external/rules_java/java/BUILD and referenced by '//java:rules-java-docs'

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

WORKSPACE:

workspace(name = "test_docs")

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "bazel_skylib",
    urls = [
        "https://github.com/bazelbuild/bazel-skylib/releases/download/1.1.1/bazel-skylib-1.1.1.tar.gz",
        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.1.1/bazel-skylib-1.1.1.tar.gz",
    ],
    sha256 = "c6966ec828da198c5d9adbaa94c05e3a1c7f21bd012a0b29ba8ddbccb2c93b0d",
)
load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
bazel_skylib_workspace()

BUILD.bazel

load("@bazel_skylib//:bzl_library.bzl", "bzl_library")

bzl_library(
    name = "rules-java-docs",
    srcs = [
        "@rules_java//java:defs.bzl",
    ],
)

What operating system are you running Bazel on?

What's the output of bazel info release?

% bazel info release
INFO: Invocation ID: b9bb1040-1962-4f14-9fee-91d653c399f0
release 5.0.0rc2

Have you found anything relevant by searching the web?

Any other information, logs, or outputs that you want to share?

[Wyverald]

@comius thoughts?

[comius]

With Bazel 5, the rules_java have been moved to the internal to Bazel itself. This has removed access to the rules java defs.bzl file. This in turn blocks our ability to generate our internal build documentation.

I'm not exactly sure what you're referring to. rules_java is still an external repository and it is imported by default via workspace prefix mechanism. The version of rules_java that is imported has not changed since 2019-07-03.

There is a "builtin" java_library implementation. But this does not change how rules_java are imported. So if you are loading a different version of rules_java in your WORKSPACE you should continue to do so.

I tested you reproduction with Bazel 4.2.2 and it results in the same error.