Users can define Pkl JARs to use for pkl_java_library outputs (#72)

Previously, the result of using the `pkl_java_library` would produce a
`java_library` the directly depends on `//pkl/private:pkl-tools`.

This has been stripped back to only include `pkl-config-java`, and if
users wish to, they can define the Pkl libraries that this uses
themselves.

All they need to do is provide one of the following libraries
themselves:

- pkl-config-java
- pkl-config-java-all
- pkl-tools

By default, if `pkl_deps` isn't defined on `pkl_java_library`, it will
continue to use `//pkl/private:pkl-config-java-internal`.

Author: KushalP

MODULE.bazel

@@ -53,6 +53,8 @@ maven = use_extension("@rules_jvm_external//:extensions.bzl", "maven")
 maven.install(
     name = "rules_pkl_deps",
     artifacts = [
+        "org.pkl-lang:pkl-tools:0.28.2",
+        "org.pkl-lang:pkl-config-java:0.28.2",
         "org.pkl-lang:pkl-tools:0.28.2",
         "org.jetbrains.kotlin:kotlin-stdlib:2.0.21",
         "com.google.code.gson:gson:2.12.1",
@@ -68,6 +70,21 @@ use_repo(
     "rules_pkl_deps",
     "unpinned_rules_pkl_deps",
 )
+maven.install(
+    name = "custom_pkl_java_library_maven_deps",
+    artifacts = [
+        "org.pkl-lang:pkl-config-java:0.28.2",
+    ],
+    lock_file = "//pkl/private:pkl_deps_custom_java_library_maven_deps_install.json",
+    repositories = [
+        "https://repo1.maven.org/maven2/",
+    ],
+)
+use_repo(
+    maven,
+    "custom_pkl_java_library_maven_deps",
+    "unpinned_custom_pkl_java_library_maven_deps",
+)
 
 bazel_binaries = use_extension(
     "@rules_bazel_integration_test//:extensions.bzl",

docs/rules_pkl_docs.md

@@ -202,7 +202,7 @@ Generate documentation website for Pkl files.
 <pre>
 load("@rules_pkl//pkl:defs.bzl", "pkl_java_library")
 
-pkl_java_library(<a href="#pkl_java_library-name">name</a>, <a href="#pkl_java_library-srcs">srcs</a>, <a href="#pkl_java_library-module_path">module_path</a>, <a href="#pkl_java_library-generate_getters">generate_getters</a>, <a href="#pkl_java_library-deps">deps</a>, <a href="#pkl_java_library-tags">tags</a>, <a href="#pkl_java_library-kwargs">kwargs</a>)
+pkl_java_library(<a href="#pkl_java_library-name">name</a>, <a href="#pkl_java_library-srcs">srcs</a>, <a href="#pkl_java_library-module_path">module_path</a>, <a href="#pkl_java_library-generate_getters">generate_getters</a>, <a href="#pkl_java_library-deps">deps</a>, <a href="#pkl_java_library-pkl_java_deps">pkl_java_deps</a>, <a href="#pkl_java_library-tags">tags</a>, <a href="#pkl_java_library-kwargs">kwargs</a>)
 </pre>
 
 Create a compiled JAR of Java source files generated from Pkl source files.
@@ -217,6 +217,7 @@ Create a compiled JAR of Java source files generated from Pkl source files.
 | <a id="pkl_java_library-module_path"></a>module_path |  List of Java module targets. Must export provide the JavaInfo provider.   |  `[]` |
 | <a id="pkl_java_library-generate_getters"></a>generate_getters |  Generate private final fields and public getter methods instead of public final fields. Defaults to True.   |  `None` |
 | <a id="pkl_java_library-deps"></a>deps |  Other targets to include in the Pkl module path when building this Java library. Must be pkl_* targets.   |  `[]` |
+| <a id="pkl_java_library-pkl_java_deps"></a>pkl_java_deps |  The Pkl `java_library` targets to include in the produced Java library as deps. Must be `JavaInfo` targets. Defaults to an internal `pkl-config-java` label.   |  `[Label("@rules_pkl//pkl/private:pkl-config-java-internal")]` |
 | <a id="pkl_java_library-tags"></a>tags |  Bazel tags to add to this target.   |  `[]` |
 | <a id="pkl_java_library-kwargs"></a>kwargs |  Further keyword arguments. E.g. visibility.   |  none |
 

pkl/private/BUILD.bazel

@@ -39,14 +39,15 @@ sh_binary(
     visibility = ["//visibility:public"],
 )
 
-# Export the `pkl-tools` library from the ruleset so `bzlmod`-enabled builds
-# can link against it.
+# Export the `pkl-config-java` library from the ruleset so it can be used in the default codegen toolchain.
+# Rules/macro implementations should not refer to this target directly (otherwise they'll take away the user's ability
+# to override it). They can instead inject their own `pkl-config-java` or `pkl-tools` on `pkl_java_library` using `pkl_deps`.
 java_library(
-    name = "pkl-tools",
+    name = "pkl-config-java-internal",
     visibility = ["//visibility:public"],
     exports = [
         artifact(
-            "org.pkl-lang:pkl-tools",
+            "org.pkl-lang:pkl-config-java",
             repository_name = "rules_pkl_deps",
         ),
     ],

pkl/private/pkl_codegen_java.bzl

@@ -113,7 +113,7 @@ _pkl_java_src_jar = rule(
     ],
 )
 
-def pkl_java_library(name, srcs, module_path = [], generate_getters = None, deps = [], tags = [], **kwargs):
+def pkl_java_library(name, srcs, module_path = [], generate_getters = None, deps = [], pkl_java_deps = [Label("//pkl/private:pkl-config-java-internal")], tags = [], **kwargs):
     """Create a compiled JAR of Java source files generated from Pkl source files.
 
     Args:
@@ -122,6 +122,7 @@ def pkl_java_library(name, srcs, module_path = [], generate_getters = None, deps
         module_path: List of Java module targets. Must export provide the JavaInfo provider.
         generate_getters: Generate private final fields and public getter methods instead of public final fields. Defaults to True.
         deps: Other targets to include in the Pkl module path when building this Java library. Must be pkl_* targets.
+        pkl_java_deps: The Pkl `java_library` targets to include in the produced Java library as deps. Must be `JavaInfo` targets. Defaults to an internal `pkl-config-java` label.
         tags: Bazel tags to add to this target.
         **kwargs: Further keyword arguments. E.g. visibility.
     """
@@ -140,11 +141,9 @@ def pkl_java_library(name, srcs, module_path = [], generate_getters = None, deps
         tags = tags,
     )
 
-    pkl_deps = [Label("//pkl/private:pkl-tools")]
-
     # Ensure that there are no duplicate entries in the deps
     all_deps = depset(
-        pkl_deps + [native.package_relative_label(m) for m in module_path],
+        pkl_java_deps + [native.package_relative_label(m) for m in module_path],
         transitive = depsets,
     )