[java-inspections] OptionalAssignedToNull: avoid warning when Optional is received from Map.get (IDEA-292883)

GitOrigin-RevId: f41b21fa9d6588247aff0b3b4c8335ddfe74e7e9

java/java-impl-inspections/src/com/intellij/codeInspection/OptionalAssignedToNullInspection.java

@@ -2,6 +2,7 @@
 package com.intellij.codeInspection;
 
 import com.intellij.codeInsight.PsiEquivalenceUtil;
+import com.intellij.codeInspection.dataFlow.DfaUtil;
 import com.intellij.codeInspection.ui.SingleCheckboxOptionsPanel;
 import com.intellij.codeInspection.util.OptionalUtil;
 import com.intellij.java.JavaBundle;
@@ -13,6 +14,8 @@ import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.psi.util.PsiTypesUtil;
 import com.intellij.psi.util.PsiUtil;
 import com.intellij.util.ObjectUtils;
+import com.intellij.util.containers.ContainerUtil;
+import com.siyeh.ig.callMatcher.CallMatcher;
 import com.siyeh.ig.psiutils.*;
 import one.util.streamex.StreamEx;
 import org.jetbrains.annotations.Nls;
@@ -22,6 +25,9 @@ import org.jetbrains.annotations.Nullable;
 import javax.swing.*;
 
 public class OptionalAssignedToNullInspection extends AbstractBaseJavaLocalInspectionTool {
+  private static final CallMatcher MAP_GET = CallMatcher.instanceCall(CommonClassNames.JAVA_UTIL_MAP, "get").parameterTypes(
+    CommonClassNames.JAVA_LANG_OBJECT);
+
   public boolean WARN_ON_COMPARISON = true;
 
   @Nullable
@@ -88,7 +94,8 @@ public class OptionalAssignedToNullInspection extends AbstractBaseJavaLocalInspe
         PsiExpression value = ExpressionUtils.getValueComparedWithNull(binOp);
         if (value != null &&
             TypeUtils.isOptional(value.getType()) &&
-            !hasSubsequentIsPresentCall(value, binOp, JavaTokenType.EQEQ.equals(binOp.getOperationTokenType()))) {
+            !hasSubsequentIsPresentCall(value, binOp, JavaTokenType.EQEQ.equals(binOp.getOperationTokenType())) &&
+            !comesFromMapGet(value)) {
           boolean useIsEmpty =
             binOp.getOperationTokenType().equals(JavaTokenType.EQEQ) &&
             PsiUtil.isLanguageLevel11OrHigher(binOp);
@@ -100,6 +107,17 @@ public class OptionalAssignedToNullInspection extends AbstractBaseJavaLocalInspe
         }
       }
 
+      private boolean comesFromMapGet(PsiExpression value) {
+        PsiLocalVariable local = ExpressionUtils.resolveLocalVariable(value);
+        if (local != null) {
+          PsiExpression initializer = ContainerUtil.getOnlyItem(DfaUtil.getVariableValues(local, value));
+          if (initializer != null) {
+            value = initializer;
+          }
+        }
+        return MAP_GET.matches(ExpressionUtils.resolveExpression(value));
+      }
+
       private boolean hasSubsequentIsPresentCall(@NotNull PsiExpression optionalExpression,
                                                  @NotNull PsiExpression previousExpression,
                                                  boolean negated) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/optionalNull/afterOptionalComparison.java

@@ -1,5 +1,6 @@
 // "Fix all 'Null value for Optional type' problems in file" "true"
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.OptionalInt;
 
@@ -38,4 +39,11 @@ public class Test {
     }
   }
 
+  void test6(Map<String, Optional<String>> map) {
+    Optional<String> result = map.get("key");
+    if (result == null) {
+      return;
+    }
+    System.out.println(result);
+  }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/optionalNull/beforeOptionalComparison.java

@@ -1,5 +1,6 @@
 // "Fix all 'Null value for Optional type' problems in file" "true"
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.OptionalInt;
 
@@ -37,4 +38,11 @@ public class Test {
     }
   }
 
+  void test6(Map<String, Optional<String>> map) {
+    Optional<String> result = map.get("key");
+    if (result == null) {
+      return;
+    }
+    System.out.println(result);
+  }
 }