From da62a731acf2ae51ade0b5ff3fcd45006eade49d Mon Sep 17 00:00:00 2001
From: Tagir Valeev <tagir.valeev@jetbrains.com>
Date: Mon, 17 Apr 2023 14:43:11 +0200
Subject: [PATCH] [java-dfa] Avoid false-positive NPE warnings inside
 java.lang.System source
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Fixes IDEA-316248 Inspection "Method invocation ‘println’ will produce ‘NullPointerException’" on System.err

GitOrigin-RevId: 0d257c09bff9712299bc749288703d057dfa3fdb
---
 .../dataFlow/java/JavaDfaValueFactory.java           |  2 +-
 .../dataFlow/fixture/SystemOutNullSource.java        | 12 ++++++++++++
 .../java/codeInspection/DataFlowInspectionTest.java  |  3 ++-
 3 files changed, 15 insertions(+), 2 deletions(-)
 create mode 100644 java/java-tests/testData/inspection/dataFlow/fixture/SystemOutNullSource.java

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/java/JavaDfaValueFactory.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/java/JavaDfaValueFactory.java
index ee8584395444..e0107dec460e 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/java/JavaDfaValueFactory.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/java/JavaDfaValueFactory.java
@@ -120,7 +120,7 @@ public final class JavaDfaValueFactory {
   private static DfaValue createReferenceValue(DfaValueFactory factory, @NotNull PsiReferenceExpression refExpr) {
     PsiElement target = refExpr.resolve();
     if (target instanceof PsiVariable variable) {
-      if (!PsiUtil.isAccessedForWriting(refExpr)) {
+      if (!PsiUtil.isAccessedForWriting(refExpr) && !PlainDescriptor.hasInitializationHacks(variable)) {
         DfaValue constValue = getConstantFromVariable(factory, variable);
         if (constValue != null && !maybeUninitializedConstant(constValue, refExpr, variable)) return constValue;
       }
diff --git a/java/java-tests/testData/inspection/dataFlow/fixture/SystemOutNullSource.java b/java/java-tests/testData/inspection/dataFlow/fixture/SystemOutNullSource.java
new file mode 100644
index 000000000000..c80936ede38c
--- /dev/null
+++ b/java/java-tests/testData/inspection/dataFlow/fixture/SystemOutNullSource.java
@@ -0,0 +1,12 @@
+// IDEA-316248
+package java.lang;
+
+import java.io.PrintStream;
+
+class System {
+  public static final PrintStream out = null;
+  
+  void test() {
+    out.println(1);
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspectionTest.java b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspectionTest.java
index 60edd3bb12b0..5c6be66608c0 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspectionTest.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspectionTest.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 2000-2023 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.java.codeInspection;
 
 import com.intellij.JavaTestUtil;
@@ -724,4 +724,5 @@ public class DataFlowInspectionTest extends DataFlowInspectionTestCase {
   public void testTryWithResourcesCloseThrows() { doTest(); }
   public void testBooleanOrEquals() { doTest(); }
   public void testDuplicatedByPointlessBooleanInspection() { doTest(); }
+  public void testSystemOutNullSource() { doTest(); }
 }