[Gradle, JS] Add diagnostic messages for js targets

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinProjectExtension.kt

@@ -98,7 +98,8 @@ open class KotlinJsProjectExtension :
     // target is public property
     // Users can write kotlin.target and it should work
     // So call of target should init default canfiguration
-    private var _target: KotlinJsTargetDsl? = null
+    internal var _target: KotlinJsTargetDsl? = null
+        private set
 
     override var target: KotlinJsTargetDsl
         get() {

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsPlugin.kt

@@ -39,6 +39,23 @@ open class KotlinJsPlugin(
             defaultJsCompilerType = PropertiesProvider(project).jsCompiler
         }
 
+        project.afterEvaluate {
+            checkNotNull(kotlinExtension._target) {
+                """
+                    Need to initialize js target.
+                    Use 
+                    kotlin {
+                        js {
+                            // Choose sub target (or both), for which js is necessary
+                            // Affect in which tests are executed and final dist (in browser is only one bundle file)
+                            browser()
+                            nodejs()
+                        }
+                    }
+                """.trimIndent()
+            }
+        }
+
         // Explicitly create configurations for main and test
         // It is because in single platform we want to declare dependencies with methods not with strings in Kotlin DSL
         // implementation("foo") instead of "implementation"("foo")

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsTarget.kt

@@ -107,7 +107,8 @@ constructor(
 
     override val browser by browserLazyDelegate
 
-    override val isBrowserConfigured: Boolean = browserLazyDelegate.isInitialized()
+    override val isBrowserConfigured: Boolean
+        get() = browserLazyDelegate.isInitialized()
 
     override fun browser(body: KotlinJsBrowserDsl.() -> Unit) {
         body(browser)
@@ -129,7 +130,8 @@ constructor(
 
     override val nodejs by nodejsLazyDelegate
 
-    override val isNodejsConfigured: Boolean = nodejsLazyDelegate.isInitialized()
+    override val isNodejsConfigured: Boolean
+        get() = nodejsLazyDelegate.isInitialized()
 
     override fun nodejs(body: KotlinJsNodeDsl.() -> Unit) {
         body(nodejs)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/KotlinJsTargetPreset.kt

@@ -12,6 +12,7 @@ import org.gradle.api.Project
 import org.jetbrains.kotlin.gradle.plugin.KotlinJsCompilerType
 import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
 import org.jetbrains.kotlin.gradle.plugin.removeJsCompilerSuffix
+import org.jetbrains.kotlin.gradle.plugin.whenEvaluated
 import org.jetbrains.kotlin.gradle.targets.js.KotlinJsTarget
 import org.jetbrains.kotlin.gradle.targets.js.KotlinJsTargetConfigurator
 import org.jetbrains.kotlin.gradle.targets.js.ir.KotlinJsIrTargetPreset
@@ -39,6 +40,25 @@ open class KotlinJsTargetPreset(
             this.irTarget = irPreset?.createTarget(
                 lowerCamelCaseName(name.removeJsCompilerSuffix(KotlinJsCompilerType.legacy), KotlinJsCompilerType.ir.name)
             )
+
+            project.whenEvaluated {
+                if (!isBrowserConfigured && !isNodejsConfigured) {
+                    project.logger.warn(
+                        """
+                            Choose sub target (or both), for which js is necessary
+                            In next releases it will be error
+                            Use
+                            kotlin {
+                                js {
+                                    // Affect in which tests are executed and final dist (in browser is only one bundle file)
+                                    browser()
+                                    nodejs()
+                                }
+                            }
+                        """.trimIndent()
+                    )
+                }
+            }
         }
     }
 

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/ir/KotlinJsIrTarget.kt

@@ -61,7 +61,8 @@ constructor(
 
     override val browser by browserLazyDelegate
 
-    override val isBrowserConfigured: Boolean = browserLazyDelegate.isInitialized()
+    override val isBrowserConfigured: Boolean
+        get() = browserLazyDelegate.isInitialized()
 
     override fun browser(body: KotlinJsBrowserDsl.() -> Unit) {
         body(browser)
@@ -82,7 +83,8 @@ constructor(
 
     override val nodejs by nodejsLazyDelegate
 
-    override val isNodejsConfigured: Boolean = nodejsLazyDelegate.isInitialized()
+    override val isNodejsConfigured: Boolean
+        get() = nodejsLazyDelegate.isInitialized()
 
     override fun nodejs(body: KotlinJsNodeDsl.() -> Unit) {
         body(nodejs)

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/ir/KotlinJsIrTargetPreset.kt

@@ -6,13 +6,10 @@
 package org.jetbrains.kotlin.gradle.targets.js.ir
 
 import org.gradle.api.Project
-import org.jetbrains.kotlin.gradle.plugin.KotlinJsCompilerType
+import org.jetbrains.kotlin.gradle.plugin.*
-import org.jetbrains.kotlin.gradle.plugin.KotlinOnlyTargetConfigurator
-import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinCompilationFactory
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinOnlyTarget
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinOnlyTargetPreset
-import org.jetbrains.kotlin.gradle.plugin.removeJsCompilerSuffix
 import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
 
 open class KotlinJsIrTargetPreset(
@@ -28,7 +25,28 @@ open class KotlinJsIrTargetPreset(
         get() = KotlinPlatformType.js
 
     override fun instantiateTarget(name: String): KotlinJsIrTarget {
-        return project.objects.newInstance(KotlinJsIrTarget::class.java, project, platformType, mixedMode)
+        return project.objects.newInstance(KotlinJsIrTarget::class.java, project, platformType, mixedMode).apply {
+            if (!mixedMode) {
+                project.whenEvaluated {
+                    if (!isBrowserConfigured && !isNodejsConfigured) {
+                        project.logger.warn(
+                            """
+                                Choose sub target (or both), for which js is necessary
+                                In next releases it will be error
+                                Use
+                                kotlin {
+                                    js {
+                                        // Affect in which tests are executed and final dist (in browser is only one bundle file)
+                                        browser()
+                                        nodejs()
+                                    }
+                                }
+                            """.trimIndent()
+                        )
+                    }
+                }
+            }
+        }
     }
 
     override fun createKotlinTargetConfigurator(): KotlinOnlyTargetConfigurator<KotlinJsIrCompilation, KotlinJsIrTarget> =