Add option to disable AP discovery in compile classpath

#KT-24530 Fixed

To disable discovery and enable avoidance for kapt tasks,
use "kapt.includeCompileClasspath = false"

plugins/kapt3/kapt3-base/src/org/jetbrains/kotlin/kapt3/base/KaptOptions.kt

@@ -47,7 +47,10 @@ class KaptOptions(
         val processingOptions: MutableMap<String, String> = mutableMapOf()
         val javacOptions: MutableMap<String, String> = mutableMapOf()
 
-        val flags: MutableSet<KaptFlag> = mutableSetOf(KaptFlag.USE_LIGHT_ANALYSIS)
+        val flags: MutableSet<KaptFlag> = mutableSetOf(
+            KaptFlag.USE_LIGHT_ANALYSIS,
+            KaptFlag.INCLUDE_COMPILE_CLASSPATH
+        )
 
         var mode: AptMode = AptMode.WITH_COMPILATION
         var detectMemoryLeaks: DetectMemoryLeaksMode = DetectMemoryLeaksMode.DEFAULT
@@ -88,7 +91,8 @@ enum class KaptFlag(val description: String) {
     USE_LIGHT_ANALYSIS("Use light analysis"),
     CORRECT_ERROR_TYPES("Correct error types"),
     MAP_DIAGNOSTIC_LOCATIONS("Map diagnostic locations"),
-    STRICT("Strict mode");
+    STRICT("Strict mode"),
+    INCLUDE_COMPILE_CLASSPATH("Detect annotation processors in compile classpath");
 }
 
 interface KaptSelector {

plugins/kapt3/kapt3-base/src/org/jetbrains/kotlin/kapt3/base/ProcessorLoader.kt

@@ -5,10 +5,12 @@
 
 package org.jetbrains.kotlin.kapt3.base
 
+import org.jetbrains.kotlin.base.kapt3.KaptFlag
 import org.jetbrains.kotlin.base.kapt3.KaptOptions
 import org.jetbrains.kotlin.kapt3.base.util.KaptLogger
 import org.jetbrains.kotlin.kapt3.base.util.info
 import java.io.Closeable
+import java.io.File
 import java.lang.reflect.Field
 import java.lang.reflect.Modifier
 import java.net.URLClassLoader
@@ -23,7 +25,12 @@ open class ProcessorLoader(private val options: KaptOptions, private val logger:
     fun loadProcessors(parentClassLoader: ClassLoader = ClassLoader.getSystemClassLoader()): LoadedProcessors {
         clearJarURLCache()
 
-        val classpath = (options.processingClasspath + options.compileClasspath).distinct()
+        val classpath = LinkedHashSet<File>().apply {
+            addAll(options.processingClasspath)
+            if (options[KaptFlag.INCLUDE_COMPILE_CLASSPATH]) {
+                addAll(options.compileClasspath)
+            }
+        }
         val classLoader = URLClassLoader(classpath.map { it.toURI().toURL() }.toTypedArray(), parentClassLoader)
         this.annotationProcessingClassLoader = classLoader
 

plugins/kapt3/kapt3-cli/src/KaptCliOption.kt

@@ -149,6 +149,11 @@ enum class KaptCliOption(
     ),
 
     DETECT_MEMORY_LEAKS_OPTION("detectMemoryLeaks", "true | false", "Detect memory leaks in annotation processors"),
+    INCLUDE_COMPILE_CLASSPATH(
+        "includeCompileClasspath",
+        "true | false",
+        "Discover annotation processors in compile classpath"
+    ),
 
     INFO_AS_WARNINGS_OPTION("infoAsWarnings", "true | false", "Show information messages as warnings"),
 

plugins/kapt3/kapt3-compiler/src/org/jetbrains/kotlin/kapt3/Kapt3Plugin.kt

@@ -109,6 +109,7 @@ class Kapt3CommandLineProcessor : CommandLineProcessor {
             INFO_AS_WARNINGS_OPTION -> setFlag(KaptFlag.INFO_AS_WARNINGS, value)
             STRICT_MODE_OPTION -> setFlag(KaptFlag.STRICT, value)
             SHOW_PROCESSOR_TIMINGS -> setFlag(KaptFlag.SHOW_PROCESSOR_TIMINGS, value)
+            INCLUDE_COMPILE_CLASSPATH -> setFlag(KaptFlag.INCLUDE_COMPILE_CLASSPATH, value)
 
             DETECT_MEMORY_LEAKS_OPTION -> setSelector(enumValues<DetectMemoryLeaksMode>(), value) { detectMemoryLeaks = it }
             APT_MODE_OPTION -> setSelector(enumValues<AptMode>(), value) { mode = it }