can be final: fix batch inspection false positives (IDEA-225311)

GitOrigin-RevId: 8c10b7b77c4362f106ee4dcb450ea9fce4631e25

java/java-analysis-impl/src/com/intellij/codeInspection/canBeFinal/CanBeFinalAnnotator.java

@@ -90,7 +90,6 @@ class CanBeFinalAnnotator extends RefGraphAnnotatorEx {
     }
   }
 
-
   @Override
   public void onMarkReferenced(RefElement refWhat,
                                RefElement refFrom,
@@ -98,18 +97,24 @@ class CanBeFinalAnnotator extends RefGraphAnnotatorEx {
                                boolean forReading,
                                boolean forWriting,
                                PsiElement referenceElement) {
+    if (!forWriting) return;
     if (!(refWhat instanceof RefField)) return;
-    if (!(refFrom instanceof RefMethod) ||
-        !((RefMethod)refFrom).isConstructor() ||
-        ((RefField)refWhat).getUastElement().getUastInitializer() != null ||
-        ((RefMethod)refFrom).getOwnerClass() != ((RefField)refWhat).getOwnerClass() ||
-        ((RefField)refWhat).isStatic()) {
-      if (forWriting &&
-          !(referencedFromClassInitializer && PsiTreeUtil.getParentOfType(referenceElement, PsiLambdaExpression.class, true) == null)) {
+    final RefField refField = (RefField)refWhat;
+    if (refFrom instanceof RefClass && refField.getOwnerClass() != refFrom) {
+      ((RefFieldImpl)refWhat).setFlag(false, CAN_BE_FINAL_MASK);
+    }
+    else if (refField.getUastElement().getUastInitializer() != null) {
+      ((RefFieldImpl)refWhat).setFlag(false, CAN_BE_FINAL_MASK);
+    }
+    else if (!(refFrom instanceof RefMethod) ||
+             !((RefMethod)refFrom).isConstructor() ||
+             ((RefMethod)refFrom).getOwnerClass() != refField.getOwnerClass() ||
+             refField.isStatic()) {
+      if (!referencedFromClassInitializer || PsiTreeUtil.getParentOfType(referenceElement, PsiLambdaExpression.class, true) != null) {
         ((RefFieldImpl)refWhat).setFlag(false, CAN_BE_FINAL_MASK);
       }
     }
-    else if (forWriting && PsiTreeUtil.getParentOfType(referenceElement, PsiLambdaExpression.class, true) != null) {
+    else if (PsiTreeUtil.getParentOfType(referenceElement, PsiLambdaExpression.class, true) != null) {
       ((RefFieldImpl)refWhat).setFlag(false, CAN_BE_FINAL_MASK);
     }
   }

java/java-tests/testData/inspection/canBeFinal/FieldAssignedFromOtherClass/expected.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+
+</problems>

java/java-tests/testData/inspection/canBeFinal/FieldAssignedFromOtherClass/src/X.java

@@ -0,0 +1,10 @@
+public final class X {
+
+  private static int blabla;
+
+  final class Other {
+    {
+      blabla = 2;
+    }
+  }
+}

java/java-tests/testData/inspection/canBeFinal/FieldAssignedInClassInitializer/expected.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+
+</problems>

java/java-tests/testData/inspection/canBeFinal/FieldAssignedInClassInitializer/src/Test.java

@@ -0,0 +1,7 @@
+public final class Test {
+
+  protected static String prefix = "";
+  static {
+    prefix = "../";
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInspection/CanBeFinalInspectionTest.java

@@ -1,4 +1,4 @@
-// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2021 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 
 package com.intellij.java.codeInspection;
 
@@ -41,6 +41,14 @@ public class CanBeFinalInspectionTest extends JavaInspectionTestCase {
     doTest();
   }
 
+  public void testFieldAssignedInClassInitializer() {
+    doTest();
+  }
+
+  public void testFieldAssignedFromOtherClass() {
+    doTest();
+  }
+
   public void testsimpleClassInheritance() {
     doTest();
   }