[devkit] Simplifiable service retrieving: fix false positives

The inspection must not suggest replacing service retrieving calls with a `getInstance` call if a `getInstance` method has a nullable return type.

GitOrigin-RevId: cd8a36698f0c1efb4c6af27962554ae36ba7266a

plugins/devkit/devkit-core/src/inspections/SimplifiableServiceRetrievingInspection.kt

@@ -8,6 +8,7 @@ import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.text.StringUtil
 import com.intellij.psi.PsiElementVisitor
 import com.intellij.uast.UastHintedVisitorAdapter
+import org.jetbrains.annotations.Nullable
 import org.jetbrains.idea.devkit.DevKitBundle
 import org.jetbrains.uast.*
 import org.jetbrains.uast.generate.UastCodeGenerationPlugin
@@ -73,9 +74,7 @@ internal class SimplifiableServiceRetrievingInspection : ServiceRetrievingInspec
   }
 
   private fun isGetInstanceProjectLevel(method: UMethod): Boolean {
-    if (!(method.isStaticOrJvmStatic && method.visibility == UastVisibility.PUBLIC && method.uastParameters.size == 1)) {
-      return false
-    }
+    if (!isApplicableForGetInstance(method) || method.uastParameters.size != 1) return false
     val param = method.uastParameters[0]
     if (param.type.canonicalText != Project::class.java.canonicalName) return false
     val qualifiedRef = getReturnExpression(method)?.returnExpression as? UQualifiedReferenceExpression ?: return false
@@ -84,9 +83,7 @@ internal class SimplifiableServiceRetrievingInspection : ServiceRetrievingInspec
   }
 
   private fun isGetInstanceApplicationLevel(method: UMethod): Boolean {
-    if (!(method.isStaticOrJvmStatic && method.visibility == UastVisibility.PUBLIC && method.uastParameters.isEmpty())) {
-      return false
-    }
+    if (!isApplicableForGetInstance(method) || method.uastParameters.isNotEmpty()) return false
     return when (val returnExpression = getReturnExpression(method)?.returnExpression) {
       is UQualifiedReferenceExpression -> {
         (componentManagerGetServiceMethods.uCallMatches(returnExpression.selector as? UCallExpression)
@@ -97,6 +94,12 @@ internal class SimplifiableServiceRetrievingInspection : ServiceRetrievingInspec
     }
   }
 
+  private fun isApplicableForGetInstance(method: UMethod): Boolean {
+    return method.isStaticOrJvmStatic &&
+           method.visibility == UastVisibility.PUBLIC &&
+           !method.javaPsi.hasAnnotation(Nullable::class.java.canonicalName)
+  }
+
   private val UMethod.isStaticOrJvmStatic: Boolean
     get() = this.isStatic || this.findAnnotation(JvmStatic::class.java.canonicalName) != null
 

plugins/devkit/devkit-java-tests/testData/inspections/simplifiableServiceRetrieving/NullableGetInstanceMethod.java

@@ -0,0 +1,25 @@
+import com.intellij.openapi.application.ApplicationManager;
+import com.intellij.openapi.components.Service;
+import org.jetbrains.annotations.Nullable;
+
+@Service
+final class MyAppService {
+  public static @Nullable MyAppService getInstance() {
+    return ApplicationManager.getApplication().getService(MyAppService.class);
+  }
+
+  void foo() {
+    MyAppService service = ApplicationManager.getApplication().getService(MyAppService.class);
+  }
+}
+
+@Service(Service.Level.PROJECT)
+final class MyProjectService {
+  public static @Nullable MyProjectService getInstance() {
+    return ApplicationManager.getApplication().getService(MyProjectService.class);
+  }
+
+  void foo() {
+    MyProjectService service = ApplicationManager.getApplication().getService(MyProjectService.class);
+  }
+}

plugins/devkit/devkit-java-tests/testSrc/org/jetbrains/idea/devkit/inspections/quickfix/SimplifiableServiceRetrievingInspectionTest.kt

@@ -23,4 +23,8 @@ internal class SimplifiableServiceRetrievingInspectionTest : SimplifiableService
   fun testTooGenericGetInstanceReturnType() {
     doTest()
   }
+
+  fun testNullableGetInstanceMethod() {
+    doTest()
+  }
 }

plugins/devkit/devkit-kotlin-tests/testData/inspections/simplifiableServiceRetrieving/NullableGetInstanceMethod.kt

@@ -0,0 +1,26 @@
+@file:Suppress("NO_REFLECTION_IN_CLASS_PATH")
+
+import com.intellij.openapi.application.ApplicationManager
+import com.intellij.openapi.components.Service
+import com.intellij.openapi.project.Project
+
+@Service
+class MyAppService {
+  companion object {
+    @JvmStatic
+    fun getInstance(): MyAppService? = ApplicationManager.getApplication().getService(MyAppService::class.java)
+  }
+}
+
+@Service(Service.Level.PROJECT)
+class MyProjectService {
+  companion object {
+    @JvmStatic
+    fun getInstance(project: Project): MyProjectService? = project.getService(MyProjectService::class.java)
+  }
+}
+
+fun test(project: Project) {
+  ApplicationManager.getApplication().getService(MyAppService::class.java)
+  project.getService(MyProjectService::class.java)
+}

plugins/devkit/devkit-kotlin-tests/testSrc/org/jetbrains/idea/devkit/kotlin/inspections/quickfix/KtSimplifiableServiceRetrievingInspectionTest.kt

@@ -56,6 +56,10 @@ internal class KtSimplifiableServiceRetrievingInspectionTest : SimplifiableServi
     doTest()
   }
 
+  fun testNullableGetInstanceMethod() {
+    doTest()
+  }
+
   fun testReturnTypeHasTypeParam() {
     doTest(DevKitBundle.message("inspection.simplifiable.service.retrieving.replace.with", "MyAppService", "getInstance"))
   }