Kotlin Facet: Avoid reparse of additional arguments during analysis

idea/idea-analysis/src/org/jetbrains/kotlin/idea/project/Platform.kt

@@ -25,7 +25,6 @@ import com.intellij.openapi.roots.ProjectFileIndex
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.cli.common.arguments.Argument
 import org.jetbrains.kotlin.cli.common.arguments.CommonCompilerArguments
-import org.jetbrains.kotlin.cli.common.arguments.parseCommandLineArguments
 import org.jetbrains.kotlin.config.*
 import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
 import org.jetbrains.kotlin.idea.compiler.configuration.Kotlin2JvmCompilerArgumentsHolder
@@ -111,17 +110,10 @@ val Module.languageVersionSettings: LanguageVersionSettings
                 this
         )
 
-        val arguments = facetSettings.compilerArguments
-        if (arguments != null) {
-            facetSettings.compilerSettings?.let { compilerSettings ->
-                parseCommandLineArguments(compilerSettings.additionalArgumentsAsList, arguments)
-            }
-        }
-
         return LanguageVersionSettingsImpl(
                 languageVersion,
                 ApiVersion.createByLanguageVersion(apiVersion),
-                arguments?.configureAnalysisFlags().orEmpty(),
+                facetSettings.mergedCompilerArguments?.configureAnalysisFlags().orEmpty(),
                 extraLanguageFeatures
         )
     }

idea/idea-jps-common/src/org/jetbrains/kotlin/config/KotlinFacetSettings.kt

@@ -19,10 +19,7 @@ package org.jetbrains.kotlin.config
 import com.intellij.openapi.components.ServiceManager
 import com.intellij.openapi.module.Module
 import com.intellij.openapi.project.Project
-import org.jetbrains.kotlin.cli.common.arguments.CommonCompilerArguments
+import org.jetbrains.kotlin.cli.common.arguments.*
-import org.jetbrains.kotlin.cli.common.arguments.K2JSCompilerArguments
-import org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments
-import org.jetbrains.kotlin.cli.common.arguments.K2MetadataCompilerArguments
 import org.jetbrains.kotlin.utils.DescriptionAware
 
 sealed class TargetPlatformKind<out Version : TargetPlatformVersion>(
@@ -83,13 +80,35 @@ class KotlinFacetSettings {
     var version = CURRENT_VERSION
     var useProjectSettings: Boolean = true
 
+    var mergedCompilerArguments: CommonCompilerArguments? = null
+        private set
+
+    // TODO: Workaround for unwanted facet settings modification on code analysis
+    // To be replaced with proper API for settings update (see BaseKotlinCompilerSettings as an example)
+    fun updateMergedArguments() {
+        val compilerArguments = compilerArguments
+        val compilerSettings = compilerSettings
+
+        mergedCompilerArguments = if (compilerArguments != null) {
+            copyBean(compilerArguments).apply {
+                if (compilerSettings != null) {
+                    parseCommandLineArguments(compilerSettings.additionalArgumentsAsList, this)
+                }
+            }
+        }
+        else null
+    }
+
     var compilerArguments: CommonCompilerArguments? = null
         set(value) {
             field = value?.unfrozen() as CommonCompilerArguments?
+            updateMergedArguments()
         }
+
     var compilerSettings: CompilerSettings? = null
         set(value) {
             field = value?.unfrozen() as CompilerSettings?
+            updateMergedArguments()
         }
 
     var languageLevel: LanguageVersion?

idea/src/org/jetbrains/kotlin/idea/facet/KotlinFacetEditorGeneralTab.kt

@@ -316,6 +316,7 @@ class KotlinFacetEditorGeneralTab(
                         }
                     }
                 }
+                updateMergedArguments()
             }
         }
     }

idea/src/org/jetbrains/kotlin/idea/facet/facetUtils.kt

@@ -238,5 +238,7 @@ fun parseCompilerArgumentsToFacet(
         with(compilerArguments::class.java.newInstance()) {
             copyFieldsSatisfying(this, compilerArguments) { exposeAsAdditionalArgument(it) || it.name in ignoredFields }
         }
+
+        updateMergedArguments()
     }
 }