pkl_java_library build fail with missing java dependency

[tjoneslo]

In the upgrade of rules_java from 8.14.0 to 8.15.2 , the java compiler gets much picker about missing transitive dependencies.

As a result trying to build a pkl_java_library (like as follows)

pkl_java_library(
    name = "schema",
    srcs = [
        "//project/src/main/resources:schema.pkl",
    ],
    generate_getters = False,
    visibility = ["//:__subpackages__"],
)

fails with this error:

ConnectService.java:68: error: [strict] Using type org.pkl.core.Duration from an indirect dependency (TOOL_INFO: "@@rules_jvm_external++maven+rules_pkl_deps//:org_pkl_lang_pkl_core"). See command below **
    public final @NonNull Duration startStopTimeout;
                          ^
 ** Please add the following dependencies: 
  @@rules_jvm_external++maven+rules_pkl_deps//:org_pkl_lang_pkl_core to //project/src/main/java/com/config/pkl/schema:schema_compiled 

The obvious solution of adding pkl_java_deps = ["@rules_pkl//:org_pkl_lang_pkl_core"], to work around this problem the build then fails with the following:

ERROR: error loading package '@@rules_pkl+//': Unable to find package for @@[unknown repo 'bazel_gazelle' requested from @@rules_pkl+]//:def.bzl: The repository '@@[unknown repo 'bazel_gazelle' requested from @@rules_pkl+]' could not be resolved: No repository visible as '@bazel_gazelle' from repository '@@rules_pkl+'.
ERROR: /project/src/main/java/com/pkl/schema/BUILD.bazel:3:17: error loading package '@@rules_pkl+//': Unable to find package for @@[unknown repo 'bazel_gazelle' requested from @@rules_pkl+]//:def.bzl: The repository '@@[unknown repo 'bazel_gazelle' requested from @@rules_pkl+]' could not be resolved: No repository visible as '@bazel_gazelle' from repository '@@rules_pkl+'. and referenced by '//build:target'

Workaround: Downgrade your rules_java to 8.14.0 until this can be fixed.

[tjoneslo]

This happens when your pkl includes an element from the PKL core library, thus requires access to the library to compile correctly.

For example. if you modify tests/pkl_codegen_java/module/animals.pkl and add age: Duration to the Animal class, it will reproduce the problem in the PKL tests.

A fix for this seem to be edit the //pkl/private:pkl-config-java-internal java library and add to the exports:

       artifact(
            "org.pkl-lang:pkl-core",
            repository_name = "rules_pkl_deps",
        ),