From a813ef19b54be2cd264c738632d8168f232de9d4 Mon Sep 17 00:00:00 2001
From: Tagir Valeev <Tagir.Valeev@jetbrains.com>
Date: Wed, 13 Oct 2021 16:14:38 +0700
Subject: [PATCH] [java-dfa] FieldChecker: correctly find parent method if we
 are inside static analyzer

DfaPsiUtil.getBlockNotNullFields may run DFA for static initializer block. If it happens to be a local/anonymous class inside a method, that outer method was incorrectly used as a context. This caused wrong state of FieldChecker and might eventually lead to StackOverflowError.

GitOrigin-RevId: a96b4527cb03d77160be3579935e47d79bfca48c
---
 .../dataFlow/jvm/FieldChecker.java               |  3 ++-
 .../dataFlow/fixture/StaticFieldInAnonymous.java | 16 ++++++++++++++++
 .../codeInspection/DataFlowInspection16Test.java |  1 +
 3 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 java/java-tests/testData/inspection/dataFlow/fixture/StaticFieldInAnonymous.java

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/jvm/FieldChecker.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/jvm/FieldChecker.java
index bbff36b44aba..d0cec80f8c8a 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/jvm/FieldChecker.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/jvm/FieldChecker.java
@@ -8,6 +8,7 @@ import com.intellij.psi.util.CachedValuesManager;
 import com.intellij.psi.util.InheritanceUtil;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.psi.util.PsiUtil;
+import com.intellij.util.ObjectUtils;
 import com.siyeh.ig.callMatcher.CallMatcher;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -19,7 +20,7 @@ public class FieldChecker {
   private final PsiClass myClass;
 
   private FieldChecker(PsiElement context) {
-    PsiMethod method = context instanceof PsiClass ? null : PsiTreeUtil.getParentOfType(context, PsiMethod.class);
+    PsiMethod method = ObjectUtils.tryCast(PsiTreeUtil.getNonStrictParentOfType(context, PsiMember.class), PsiMethod.class);
     PsiClass contextClass = method != null ? method.getContainingClass() : context instanceof PsiClass ? (PsiClass)context : null;
     myClass = contextClass;
     if (method == null || myClass == null) {
diff --git a/java/java-tests/testData/inspection/dataFlow/fixture/StaticFieldInAnonymous.java b/java/java-tests/testData/inspection/dataFlow/fixture/StaticFieldInAnonymous.java
new file mode 100644
index 000000000000..3625f8db1107
--- /dev/null
+++ b/java/java-tests/testData/inspection/dataFlow/fixture/StaticFieldInAnonymous.java
@@ -0,0 +1,16 @@
+public class StaticFieldInAnonymous {
+  void test() {
+    Runnable r = new Runnable() {
+      private static final String s;
+
+      static {
+        s = "foo";
+      }
+
+      @Override
+      public void run() {
+        if (<warning descr="Condition 's == null' is always 'false'">s == null</warning>) {}
+      }
+    };
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection16Test.java b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection16Test.java
index 41b42128b349..9ef2c01a8fc8 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection16Test.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection16Test.java
@@ -38,4 +38,5 @@ public class DataFlowInspection16Test extends DataFlowInspectionTestCase {
                        "public @interface NonnullByDefault {}");
     doTest(); 
   }
+  public void testStaticFieldInAnonymous() { doTest(); }
 }
\ No newline at end of file