From 4ba3bce5f4399b4951001f9d8dc34dec3515ec37 Mon Sep 17 00:00:00 2001
From: Tagir Valeev <Tagir.Valeev@jetbrains.com>
Date: Fri, 27 Sep 2019 10:23:02 +0700
Subject: [PATCH] HardcodedContracts: support Deque#getFirst, getLast;
 Queue#element

Fixes IDEA-223629 'Method invocation may produce NullPointerException' false positive for ArrayDeque.pollFirst()

GitOrigin-RevId: e1284cb51c0a1f5a12683a57c58b085de6e5b705
---
 .../codeInspection/dataFlow/HardcodedContracts.java        | 5 ++++-
 .../testData/inspection/dataFlow/fixture/QueuePeek.java    | 7 +++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/HardcodedContracts.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/HardcodedContracts.java
index 5d18c48f5338..f9987dfdcce3 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/HardcodedContracts.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/HardcodedContracts.java
@@ -109,7 +109,10 @@ public class HardcodedContracts {
                 ContractValue.qualifier().specialField(SpecialField.COLLECTION_SIZE), RelationType.EQ, ContractValue.zero(), returnFalse())))
     .register(instanceCall(JAVA_UTIL_LIST, "get").parameterTypes("int"),
               ContractProvider.of(specialFieldRangeContract(0, RelationType.LT, SpecialField.COLLECTION_SIZE)))
-    .register(instanceCall("java.util.SortedSet", "first", "last").parameterCount(0),
+    .register(anyOf(
+      instanceCall("java.util.SortedSet", "first", "last").parameterCount(0),
+      instanceCall("java.util.Deque", "getFirst", "getLast").parameterCount(0),
+      instanceCall("java.util.Queue", "element").parameterCount(0)),
               ContractProvider.of(singleConditionContract(
                 ContractValue.qualifier().specialField(SpecialField.COLLECTION_SIZE), RelationType.EQ,
                 ContractValue.zero(), fail())))
diff --git a/java/java-tests/testData/inspection/dataFlow/fixture/QueuePeek.java b/java/java-tests/testData/inspection/dataFlow/fixture/QueuePeek.java
index f3e29161d0b2..ac78beddab7d 100644
--- a/java/java-tests/testData/inspection/dataFlow/fixture/QueuePeek.java
+++ b/java/java-tests/testData/inspection/dataFlow/fixture/QueuePeek.java
@@ -26,4 +26,11 @@ class ThisAsVariable {
   void notCheck(Queue<String> queue) {
     System.out.println(queue.peek().<warning descr="Method invocation 'trim' may produce 'NullPointerException'">trim</warning>());
   }
+
+  void checkGetFirstPollFirst(Deque<String> queue) {
+    if ("bar".equals(queue.getFirst())) {
+      String first = queue.pollFirst();
+      System.out.println(first.toString());
+    }
+  }
 }