IDEA-122624 @Contract fails on vararg methods

java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java

@@ -1414,11 +1414,22 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
       return false;
     }
 
+    PsiMethod method = expression.resolveMethod();
+    if (method == null) {
+      return false;
+    }
+
+    final int paramCount = method.getParameterList().getParametersCount();
+    boolean varArgs = method.isVarArgs();
     final PsiExpression[] args = expression.getArgumentList().getExpressions();
+    if (varArgs && args.length < paramCount - 1 || !varArgs && args.length != paramCount) {
+      return false;
+    }
+    
     List<MethodContract> contracts = ContainerUtil.findAll(_contracts, new Condition<MethodContract>() {
       @Override
       public boolean value(MethodContract contract) {
-        return args.length == contract.arguments.length;
+        return paramCount == contract.arguments.length;
       }
     });
     if (contracts.isEmpty()) {
@@ -1428,6 +1439,12 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
     for (PsiExpression arg : args) {
       arg.accept(this);
     }
+    if (varArgs) {
+      for (int i = 0; i < args.length - paramCount + 1; i++) {
+        addInstruction(new PopInstruction());
+      }
+      pushUnknown();
+    }
 
     if (contracts.size() > 1) {
       addInstruction(new DupInstruction(args.length, contracts.size() - 1));

java/java-tests/testData/inspection/dataFlow/fixture/ContractVarargs.java

@@ -0,0 +1,30 @@
+import org.jetbrains.annotations.Contract;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+class Contracts {
+
+  public void simpleFail(@Nullable String message) {
+    notBlank(message);
+    log(message);
+  }
+
+  @Contract("_->fail")
+  private void notBlank(@Nullable Object message) {
+
+  }
+
+  @Contract("_,_,_->fail")
+  private void notBlank(@Nullable Object o, String message, Object... args) {
+
+  }
+
+  public void varargFail(@Nullable String message) {
+    notBlank(message, "Message should not be blank");
+    log(message); // highlighted
+  }
+
+  public void log(@NotNull String message) {
+    System.out.println(message);
+  }
+}

java/java-tests/testSrc/com/intellij/codeInspection/DataFlowInspectionTest.java

@@ -274,6 +274,7 @@ public class DataFlowInspectionTest extends LightCodeInsightFixtureTestCase {
   public void testContractWithNullable() { doTest(); }
   public void testContractPreservesUnknownNullability() { doTest(); }
   public void testContractSeveralClauses() { doTest(); }
+  public void testContractVarargs() { doTest(); }
 
   public void testBoxingImpliesNotNull() { doTest(); }
   public void testLargeIntegersAreNotEqualWhenBoxed() { doTest(); }