From 203a70e40ff260e4510d5a0a7a2069f4ea6f865a Mon Sep 17 00:00:00 2001
From: Tagir Valeev <Tagir.Valeev@jetbrains.com>
Date: Mon, 3 Jun 2019 16:32:40 +0700
Subject: [PATCH] DfaMemoryStateImpl: avoid exponential blow up of canonicalize
 calls

GitOrigin-RevId: 61c65025d6f6626d500a0174a96d129dc124147e
---
 .../dataFlow/DfaMemoryStateImpl.java          | 12 +++-
 .../dataFlow/fixture/ManyNestedOptionals.java | 60 +++++++++++++++++++
 .../DataFlowInspection8Test.java              |  1 +
 3 files changed, 71 insertions(+), 2 deletions(-)
 create mode 100644 java/java-tests/testData/inspection/dataFlow/fixture/ManyNestedOptionals.java

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
index e25386f97319..c3d205e56d8a 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/DfaMemoryStateImpl.java
@@ -1419,8 +1419,16 @@ public class DfaMemoryStateImpl implements DfaMemoryState {
   private DfaVariableValue canonicalize(DfaVariableValue var) {
     DfaVariableValue qualifier = var.getQualifier();
     if (qualifier != null) {
-      EqClass eqClass = getEqClass(qualifier);
-      return var.withQualifier(eqClass == null ? canonicalize(qualifier) : Objects.requireNonNull(eqClass.getCanonicalVariable()));
+      Integer index = myIdToEqClassesIndices.get(qualifier.getID());
+      if (index == null) {
+        qualifier = canonicalize(qualifier);
+        index = myIdToEqClassesIndices.get(qualifier.getID());
+        if (index == null) {
+          return var.withQualifier(qualifier);
+        }
+      }
+
+      return var.withQualifier(Objects.requireNonNull(myEqClasses.get(index).getCanonicalVariable()));
     }
     return var;
   }
diff --git a/java/java-tests/testData/inspection/dataFlow/fixture/ManyNestedOptionals.java b/java/java-tests/testData/inspection/dataFlow/fixture/ManyNestedOptionals.java
new file mode 100644
index 000000000000..363938468a0d
--- /dev/null
+++ b/java/java-tests/testData/inspection/dataFlow/fixture/ManyNestedOptionals.java
@@ -0,0 +1,60 @@
+import java.util.Optional;
+
+class App {
+  public static void main(String[] args) {
+    Optional.of("foo")
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x))
+      .map(x -> Optional.of(x));
+  }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection8Test.java b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection8Test.java
index cfce24858aa6..359e77503c54 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection8Test.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInspection/DataFlowInspection8Test.java
@@ -246,4 +246,5 @@ public class DataFlowInspection8Test extends DataFlowInspectionTestCase {
   }
 
   public void testLambdaWritesArrayInTry() { doTest(); }
+  public void testManyNestedOptionals() { doTest(); }
 }
\ No newline at end of file