Spring Support: Report object declarations in "Final Kotlin class or function with Spring annotation" inspection

#KT-12148 Fixed

ChangeLog.md

@@ -58,6 +58,7 @@ Issues fixed:
 - [KT-12366](https://youtrack.jetbrains.com/issue/KT-12366) Fixed exception on analyzing class declaration upon annotation typing
 - [KT-12122](https://youtrack.jetbrains.com/issue/KT-12122) Fixed line marker popup on functions with @Qualifier-annotated parameters
 - [KT-12363](https://youtrack.jetbrains.com/issue/KT-12363) Fixed "Autowired members defined in invalid Spring bean (Kotlin)" inspection description
+- [KT-12148](https://youtrack.jetbrains.com/issue/KT-12148) Warn about object declarations annotated with Spring `@Configuration`/`@Component`/etc.
 
 #### Debugger
 

ultimate/src/org/jetbrains/kotlin/idea/spring/inspections/KotlinFinalClassOrFunSpringInspection.kt

@@ -54,13 +54,15 @@ class KotlinFinalClassOrFunSpringInspection : AbstractKotlinInspection() {
 
     private fun getMessage(declaration: KtNamedDeclaration): String? {
         when (declaration) {
-            is KtClass -> {
+            is KtClassOrObject -> {
                 val lightClass = declaration.toLightClass() ?: return null
-                when {
+                val annotation = when {
-                    SpringConfiguration.META.getJamElement(lightClass) != null -> return "@Configuration class should be declared open"
+                    SpringConfiguration.META.getJamElement(lightClass) != null -> "@Configuration"
-                    SpringComponent.META.getJamElement(lightClass) != null -> return "@Component class should be declared open"
+                    SpringComponent.META.getJamElement(lightClass) != null -> "@Component"
-                    SpringTransactionalComponent.META.getJamElement(lightClass) != null -> return "@Transactional class should be declared open"
+                    SpringTransactionalComponent.META.getJamElement(lightClass) != null -> "@Transactional"
+                    else -> return null
                 }
+                return if (declaration is KtClass) "$annotation class should be declared open" else "$annotation should not be applied to object declaration "
             }
 
             is KtNamedFunction -> {
@@ -79,17 +81,19 @@ class KotlinFinalClassOrFunSpringInspection : AbstractKotlinInspection() {
             override fun visitNamedDeclaration(declaration: KtNamedDeclaration) {
                 when (declaration) {
                     is KtClass -> if (declaration.isInheritable()) return
+                    is KtObjectDeclaration -> {}
                     is KtNamedFunction -> if (declaration.isOverridable()) return
                     else -> return
                 }
 
                 val message = getMessage(declaration) ?: return
 
+                val fixes = if (declaration !is KtObjectDeclaration) arrayOf(QuickFix(declaration)) else LocalQuickFix.EMPTY_ARRAY
                 holder.registerProblem(
                         declaration.nameIdentifier ?: declaration,
                         message,
                         ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
-                        QuickFix(declaration)
+                        *fixes
                 )
             }
         }

ultimate/testData/inspections/spring/finalSpringAnnotatedDeclaration/inspectionData/expected.xml

@@ -127,4 +127,36 @@
         <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Final Kotlin class or function with Spring annotation</problem_class>
         <description>@Transactional function should be declared open</description>
     </problem>
+    <problem>
+        <file>test.kt</file>
+        <line>106</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Final Kotlin class or function with Spring annotation</problem_class>
+        <description>@Configuration should not be applied to object declaration</description>
+    </problem>
+    <problem>
+        <file>test.kt</file>
+        <line>109</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Final Kotlin class or function with Spring annotation</problem_class>
+        <description>@Configuration should not be applied to object declaration</description>
+    </problem>
+    <problem>
+        <file>test.kt</file>
+        <line>112</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Final Kotlin class or function with Spring annotation</problem_class>
+        <description>@Component should not be applied to object declaration</description>
+    </problem>
+    <problem>
+        <file>test.kt</file>
+        <line>115</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="WARNING_ATTRIBUTES">Final Kotlin class or function with Spring annotation</problem_class>
+        <description>@Transactional should not be applied to object declaration</description>
+    </problem>
 </problems>

ultimate/testData/inspections/spring/finalSpringAnnotatedDeclaration/test.kt

@@ -98,4 +98,18 @@ open class Trans2 {
 
     @MyTransactional
     open fun foo4() = Component4()
-}
+}
+
+// Object declarations
+
+@Configuration
+object Application5
+
+@MyConfiguration
+object Application6
+
+@Component
+object Component3
+
+@Transactional
+object Trans3