Exmaple of using ksp without leveraging kapt architecture

examples/ksp/BUILD

@@ -14,7 +14,7 @@ load("@rules_java//java:defs.bzl", "java_binary", "java_plugin")
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-load("@rules_kotlin//kotlin:core.bzl", "define_kt_toolchain", "kt_ksp_plugin")
+load("@rules_kotlin//kotlin:core.bzl", "define_kt_toolchain", "kt_compiler_plugin", "kt_ksp_plugin", "kt_plugin_cfg")
 load("@rules_kotlin//kotlin:jvm.bzl", "kt_jvm_library")
 
 package(default_visibility = ["//visibility:public"])
@@ -81,3 +81,73 @@ build_test(
         "//:coffee_app_deploy.jar",
     ],
 )
+
+kt_compiler_plugin(
+    name = "ksp",
+    compile_phase = True,
+    id = "com.google.devtools.ksp.symbol-processing",
+    options = {
+        "apclasspath": "{classpath}",
+        # projectBaseDir shouldn't matter because incremental is disabled
+        "projectBaseDir": "{temp}",
+        # Disable incremental mode
+        "incremental": "false",
+        # Directory where class files are written to. Files written to this directory are class
+        # files being written directly from the annotation processor, not Kotlinc
+        "classOutputDir": "{generatedClasses}",
+        # Directory where generated Java sources files are written to
+        "javaOutputDir": "{generatedSources}",
+        # Directory where generated Kotlin sources files are written to
+        "kotlinOutputDir": "{generatedSources}",
+        # Directory where META-INF data is written to. This might not be the most ideal place to
+        # write this. Maybe just directly to the classes directory?
+        "resourceOutputDir": "{generatedSources}",
+        # TODO(bencodes) Not sure what this directory is yet.
+        "kspOutputDir": "{temp}",
+        # Directory to write KSP caches. Shouldn't matter because incremental is disabled
+        "cachesDir": "{temp}",
+        # Include in compilation as an example. This should be processed in the stubs phase.
+        "withCompilation": "true",
+        # Set returnOkOnError to false because we want to fail the build if there are any errors
+        "returnOkOnError": "false",
+        "allWarningsAsErrors": "false",
+    },
+    deps = [
+        "@rules_kotlin//kotlin/compiler:symbol-processing-api",
+        "@rules_kotlin//kotlin/compiler:symbol-processing-cmdline",
+    ],
+)
+
+kt_plugin_cfg(
+    name = "ksp_moshi",
+    options = {
+    },
+    plugin = ":ksp",
+    deps = [
+        "@maven//:com_squareup_moshi_moshi",
+        "@maven//:com_squareup_moshi_moshi_kotlin",
+        "@maven//:com_squareup_moshi_moshi_kotlin_codegen",
+    ],
+)
+
+kt_jvm_library(
+    name = "raw_ksp_coffee_app_lib",
+    srcs = ["CoffeeAppModel.kt"],
+    plugins = [
+        "//:ksp",
+        "//:ksp_moshi",
+    ],
+    deps = [
+        "@maven//:com_google_auto_service_auto_service_annotations",
+        "@maven//:com_google_auto_value_auto_value_annotations",
+        "@maven//:com_squareup_moshi_moshi",
+        "@maven//:com_squareup_moshi_moshi_kotlin",
+    ],
+)
+
+build_test(
+    name = "raw_ksp_lib_test",
+    targets = [
+        "//:raw_ksp_coffee_app_lib",
+    ],
+)

examples/ksp/MODULE.bazel

@@ -0,0 +1,6 @@
+###############################################################################
+# Bazel now uses Bzlmod by default to manage external dependencies.
+# Please consider migrating your external dependencies from WORKSPACE to MODULE.bazel.
+#
+# For more details, please check https://github.com/bazelbuild/bazel/issues/18958
+###############################################################################

kotlin/internal/jvm/impl.bzl

@@ -385,40 +385,39 @@ def _deshade_embedded_kotlinc_jars(target, ctx, jars, deps):
         ],
     )
 
-def _resolve_plugin_options(id, string_dict):
+def _resolve_plugin_options(id, string_list_dict, expand_location):
     """
     Resolves plugin options from a string dict to a dict of strings.
 
     Args:
         id: the plugin id
-        string_dict: a dict of strings
+        string_list_dict: a dict of list[string].
     Returns:
         a dict of strings
     """
     options = []
-    for (k, v) in string_dict.items():
-        if "=" in k:
-            fail("kt_compiler_plugin options keys cannot contain the = symbol")
-        options.append(KtCompilerPluginOption(id = id, value = k + "=" + v))
+    for (k, vs) in string_list_dict.items():
+        for v in vs:
+            if "=" in k:
+                fail("kotlin compiler option keys cannot contain the = symbol")
+            value = k + "=" + expand_location(v) if v else k
+            options.append(KtCompilerPluginOption(id = id, value = value))
     return options
 
 # This is naive reference implementation for resolving configurations.
 # A more complicated plugin will need to provide its own implementation.
-def _resolve_plugin_cfg(info, options, deps):
-    classpath = []
-    for dep in deps:
-        if JavaInfo in dep:
-            classpath.append(dep[JavaInfo].compile_jars)
+def _resolve_plugin_cfg(info, options, deps, expand_location):
+    ji = java_common.merge([dep[JavaInfo] for dep in deps if JavaInfo in dep])
+    classpath = depset(ji.runtime_output_jars, transitive = [ji.transitive_runtime_jars])
     return KtPluginConfiguration(
         id = info.id,
-        options = _resolve_plugin_options(info.id, options),
-        classpath = depset(transitive = classpath),
+        options = _resolve_plugin_options(info.id, options, expand_location),
+        classpath = classpath,
         data = depset(),
     )
 
 def kt_compiler_plugin_impl(ctx):
     plugin_id = ctx.attr.id
-    options = _resolve_plugin_options(plugin_id, ctx.attr.options)
 
     deps = ctx.attr.deps
     info = None
@@ -437,6 +436,9 @@ def kt_compiler_plugin_impl(ctx):
 
     classpath = depset(info.runtime_output_jars, transitive = [info.transitive_runtime_jars])
 
+    # TODO(1035): Migrate kt_compiler_plugin.options to string_list_dict
+    options = _resolve_plugin_options(plugin_id, {k: [v] for (k, v) in ctx.attr.options.items()}, ctx.expand_location)
+
     return [
         DefaultInfo(files = classpath),
         _KtCompilerPluginInfo(
@@ -451,7 +453,7 @@ def kt_compiler_plugin_impl(ctx):
 
 def kt_plugin_cfg_impl(ctx):
     plugin = ctx.attr.plugin[_KtCompilerPluginInfo]
-    return plugin.resolve_cfg(plugin, ctx.attr.options, ctx.attr.deps)
+    return plugin.resolve_cfg(plugin, ctx.attr.options, ctx.attr.deps, ctx.expand_location)
 
 def kt_ksp_plugin_impl(ctx):
     info = java_common.merge([dep[JavaInfo] for dep in ctx.attr.deps])

kotlin/internal/jvm/jvm.bzl

@@ -622,9 +622,10 @@ kt_plugin_cfg = rule(
         "plugin": attr.label(
             doc = "The plugin to associate with this configuration",
             providers = [_KtCompilerPluginInfo],
+            mandatory = True,
         ),
-        "options": attr.string_dict(
-            doc = "A list of plugin configuration options.",
+        "options": attr.string_list_dict(
+            doc = "A dictionary of flag to values to be used as plugin configuration options.",
         ),
         "deps": attr.label_list(
             doc = "Dependencies for this configuration.",

src/main/kotlin/io/bazel/kotlin/builder/tasks/jvm/CompilationTask.kt

@@ -97,13 +97,15 @@ internal fun JvmCompilationTask.plugins(
       xFlag("plugin", it)
     }
 
-    val dirTokens = mapOf(
+    val optionTokens = mapOf(
       "{generatedClasses}" to directories.generatedClasses,
       "{stubs}" to directories.stubs,
+      "{temp}" to directories.temp,
       "{generatedSources}" to directories.generatedSources,
+      "{classpath}" to classpath.joinToString(File.pathSeparator)
     )
     options.forEach { opt ->
-      val formatted = dirTokens.entries.fold(opt) { formatting, (token, value) ->
+      val formatted = optionTokens.entries.fold(opt) { formatting, (token, value) ->
         formatting.replace(token, value)
       }
       flag("-P", "plugin:$formatted")

src/main/starlark/core/plugin/providers.bzl

@@ -13,7 +13,8 @@ KtCompilerPluginInfo = provider(
         "stubs": "Run this plugin during kapt stub generation.",
         "compile": "Run this plugin during koltinc compilation.",
         "options": "List of plugin options, represented as KtCompilerPluginOption, to be passed to the compiler",
-        "resolve_cfg": """"A Callable[[KtCompilerPluginInfo, Dict[str,str], List[Target], KtPluginConfiguration] that resolves an associated plugin configuration.""",
+        "resolve_cfg": "A Callable[[KtCompilerPluginInfo, Dict[str,str], List[Target], KtPluginConfiguration]" +
+                       " that resolves an associated plugin configuration.",
     },
 )
 

src/main/starlark/core/repositories/setup.bzl

@@ -29,8 +29,6 @@ def kt_configure():
 
     native.register_toolchains("@released_rules_kotlin//kotlin/internal:default_toolchain")
 
-    native.register_toolchains("@released_rules_kotlin//kotlin/internal:default_toolchain")
-
     maven_install(
         name = "kotlin_rules_maven",
         fetch_sources = True,