Add experimental Kotlin incremental compilation

MODULE.bazel

@@ -29,7 +29,9 @@ use_repo(
     "com_github_jetbrains_kotlin",
     "com_github_jetbrains_kotlin_git",
     "com_github_pinterest_ktlint",
+    "kotlin_build_tools_api",
     "kotlin_build_tools_impl",
+    "kotlin_compiler_embeddable",
     "kotlinx_serialization_core_jvm",
     "kotlinx_serialization_json",
     "kotlinx_serialization_json_jvm",

kotlin/internal/jvm/compile.bzl

@@ -463,6 +463,7 @@ def _run_kt_builder_action(
     args.add_all("--classpath", compile_deps.compile_jars)
     args.add("--reduced_classpath_mode", toolchains.kt.experimental_reduce_classpath_mode)
     args.add("--build_tools_api", toolchains.kt.experimental_build_tools_api)
+    args.add("--incremental_compilation", toolchains.kt.experimental_incremental_compilation)
     args.add_all("--sources", srcs.all_srcs, omit_if_empty = True)
     args.add_all("--source_jars", srcs.src_jars + generated_src_jars, omit_if_empty = True)
     args.add_all("--deps_artifacts", deps_artifacts, omit_if_empty = True)

kotlin/internal/toolchains.bzl

@@ -91,7 +91,8 @@ def _kotlin_toolchain_impl(ctx):
         experimental_strict_kotlin_deps = ctx.attr.experimental_strict_kotlin_deps,
         experimental_report_unused_deps = ctx.attr.experimental_report_unused_deps,
         experimental_reduce_classpath_mode = ctx.attr.experimental_reduce_classpath_mode,
-        experimental_build_tools_api = ctx.attr.experimental_build_tools_api,
+        experimental_build_tools_api = ctx.attr.experimental_build_tools_api[BuildSettingInfo].value,
+        experimental_incremental_compilation = ctx.attr.experimental_incremental_compilation[BuildSettingInfo].value,
         javac_options = ctx.attr.javac_options[JavacOptions] if ctx.attr.javac_options else None,
         kotlinc_options = ctx.attr.kotlinc_options[KotlincOptions] if ctx.attr.kotlinc_options else None,
         empty_jar = ctx.file._empty_jar,
@@ -248,9 +249,15 @@ _kt_toolchain = rule(
                 "KOTLINBUILDER_REDUCED",
             ],
         ),
-        "experimental_build_tools_api": attr.bool(
+        "experimental_build_tools_api": attr.label(
             doc = "Enables experimental support for Build Tools API integration",
             default = False,
+            default = Label("//kotlin/settings:experimental_build_tools_api"),
+        ),
+        "experimental_incremental_compilation": attr.label(
+            doc = "TODO",
+            default = False,
+            default = Label("//kotlin/settings:experimental_incremental_compilation"),
         ),
         "javac_options": attr.label(
             doc = "Compiler options for javac",
@@ -327,6 +334,7 @@ def define_kt_toolchain(
         experimental_reduce_classpath_mode = None,
         experimental_multiplex_workers = None,
         experimental_build_tools_api = None,
+        experimental_incremental_compilation = None,
         javac_options = Label("//kotlin/internal:default_javac_options"),
         kotlinc_options = Label("//kotlin/internal:default_kotlinc_options"),
         jvm_stdlibs = None,
@@ -356,6 +364,7 @@ def define_kt_toolchain(
         experimental_report_unused_deps = experimental_report_unused_deps,
         experimental_reduce_classpath_mode = experimental_reduce_classpath_mode,
         experimental_build_tools_api = experimental_build_tools_api,
+        experimental_incremental_compilation = experimental_incremental_compilation,
         javac_options = javac_options,
         kotlinc_options = kotlinc_options,
         visibility = ["//visibility:public"],

kotlin/settings/BUILD.bazel

@@ -48,3 +48,9 @@ bool_flag(
     build_setting_default = False,
     visibility = ["//visibility:public"],
 )
+
+bool_flag(
+    name = "experimental_incremental_compilation",
+    build_setting_default = False,
+    visibility = ["//visibility:public"],
+)

kotlin/settings/BUILD.release.bazel

@@ -40,3 +40,10 @@ bool_flag(
     build_setting_default = False,
     visibility = ["//visibility:public"],
 )
+
+# --@rules_kotlin//kotlin/settings:experimental_incremental_compilation=True
+bool_flag(
+    name = "experimental_incremental_compilation",
+    build_setting_default = False,
+    visibility = ["//visibility:public"],
+)