incompatible_load_java_rules_from_bzl: load the Java rules from @rules_java

[iirina]

Flag: --incompatible_load_java_rules_from_bzl
Available since: 0.28
Will be flipped in: 1.0
Tracking issue: #8741

java_library, java_binary, java_test, java_import, java_lite_proto_library, java_proto_library,
java_package_configuration, java_plugin, java_runtime, java_toolchain have to be loaded from @rules_java.

For example if you are using java_library, add the following load statement to your BUILD/bzl file.
load("@rules_java//java:defs.bzl", "java_library")

Migration

Add rules_java repositories to your WORKSPACE file and load its dependecies:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
http_archive(
    name = "rules_java",
    url = "https://github.com/bazelbuild/rules_java/releases/download/0.1.1/rules_java-0.1.1.tar.gz",
    sha256 = "220b87d8cfabd22d1c6d8e3cdb4249abd4c93dcc152e0667db061fb1b957ee68",
)
load("@rules_java//java:repositories.bzl", "rules_java_dependencies", "rules_java_toolchains")
rules_java_dependencies()
rules_java_toolchains()

Fix all your BUILD files that use Java rules to include the load statement. Use buildifier to automatically update all your BUILD files:

buildifier --lint=fix -warnings=native-java -r path/to/your/workspace/root/dir

[iirina]

Currently the builds will fail with --incompatible_load_java_rules_from_bzl because the java_tools are released separately and do not use the macro definitions yet. This will be fixed by updating BUILD.java_tools and releasing new java_tools versions.

[iirina]

Repositories referenced by bazel that use the native java rules and have to be migrated & upgraded before migrating bazel itself:

• skydoc: Add @rules_java repository to skydoc. skydoc#202, Update the skydoc version. #8876
• java_tools_langtools_javac{9, 10, 11, 12}: Update langtools_jdk repositories to load @rules_java. #8915
• bazel_j2objc: Load the java rules from @rules_java repository. google/j2objc#1060, Update j2objc #8912
• desugar_jdk_libs: Load the java rules from @rules_java repository. google/desugar_jdk_libs#2
• bazel_toolchains: Add load statement for rules_java. bazel-toolchains#638
• bazel_rbe_toolchains

[Yannic]

@iirina Can we update the description to include the load statement so users will know to include them?

load("@rules_java//java:repositories.bzl", "rules_java_dependencies", "rules_java_toolchains")
rules_java_dependencies()
rules_java_toolchains()

[dslomov]

Will migration tooling be available to do the migration? (based on buildifier)

[iirina]

@dslomov Yes I updated the migration notes to include using buildifier.

[lberki]

We gave up on this :(

[MikhailTymchukFT]

@lberki Can you please elaborate?
And what about tracking issue?

[lberki]

Erm, sorry for the curt answer. We decided not to require everyone to add a load() statement to every single BUILD file because it's too much churn. The current plan is to "pretend" that the eventual C++/Java rules written in Starlark are load()ed everywhere.

We might revisit this decision once they are reasonably stable and once we decide where exactly they need to be load()ed from, but now is not the time. I'll also close the tracking issue.