[infer][nullable checker] add tests for the early return

Reviewed By: sblackshear

Differential Revision: D6891113

fbshipit-source-id: a614641

infer/tests/codetoanalyze/cpp/nullable/issues.exp

@@ -20,6 +20,8 @@ codetoanalyze/cpp/nullable/method.cpp, methodAlwaysCheckedForNullOkay, 1, NULL_T
 codetoanalyze/cpp/nullable/method.cpp, methodAlwaysCheckedForNullOkay, 2, NULL_DEREFERENCE, [start of procedure methodAlwaysCheckedForNullOkay(),Condition is true,start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject,Condition is true,start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject]
 codetoanalyze/cpp/nullable/method.cpp, methodCallOnFieldOfNullableObjectBad, 2, NULLABLE_DEREFERENCE, [dereference of &p,assignment of the nullable value,definition of mayReturnNullObject]
 codetoanalyze/cpp/nullable/method.cpp, methodCallOnFieldOfNullableObjectBad, 2, NULL_DEREFERENCE, [start of procedure methodCallOnFieldOfNullableObjectBad(),start of procedure mayReturnNullObject,Condition is true,return from a call to T_mayReturnNullObject]
+codetoanalyze/cpp/nullable/method.cpp, methodCheckedForNullAndReturnOkay, 1, NULL_TEST_AFTER_DEREFERENCE, [start of procedure methodCheckedForNullAndReturnOkay(),start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject,Condition is false]
+codetoanalyze/cpp/nullable/method.cpp, methodCheckedForNullAndReturnOkay, 4, NULL_DEREFERENCE, [start of procedure methodCheckedForNullAndReturnOkay(),start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject,Condition is false,start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject]
 codetoanalyze/cpp/nullable/method.cpp, methodCheckedForNullOkay, 1, NULL_TEST_AFTER_DEREFERENCE, [start of procedure methodCheckedForNullOkay(),start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject,Condition is false]
 codetoanalyze/cpp/nullable/method.cpp, methodCheckedForNullOkay, 2, NULL_DEREFERENCE, [start of procedure methodCheckedForNullOkay(),start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject,Condition is true,start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject]
 codetoanalyze/cpp/nullable/method.cpp, methodNotAlwaysCheckedForNullBad, 1, NULL_TEST_AFTER_DEREFERENCE, [start of procedure methodNotAlwaysCheckedForNullBad(),Condition is false,start of procedure mayReturnNullObject,Condition is false,return from a call to T_mayReturnNullObject,Condition is false]

infer/tests/codetoanalyze/cpp/nullable/method.cpp

@@ -97,6 +97,13 @@ void methodCheckedForNullOkay(T* t) {
   }
 }
 
+void methodCheckedForNullAndReturnOkay(T* t) {
+  if (t->mayReturnNullObject() == nullptr) {
+    return;
+  }
+  t->mayReturnNullObject()->doSomething(); // does not report here
+}
+
 void reportsViolationOutsideOfNullCheckBad(T* t) {
   if (t->mayReturnNullObject() != nullptr) {
     t->mayReturnNullObject()->doSomething(); // does not report here

infer/tests/codetoanalyze/java/checkers/NullableViolation.java

@@ -43,6 +43,13 @@ public class NullableViolation {
     }
   }
 
+  void nullableMethodCheckedForNullAndReturnOkay() {
+    if (returnsNullable() == null) {
+        return;
+    }
+    returnsNullable().doSomething(); // does not report here
+  }
+
   void dereferenceNullableMethodIncorrectlyCheckedForNullBad() {
     if (returnsNullable() == null) {
       returnsNullable().doSomething(); // reports here

infer/tests/codetoanalyze/objc/nullable/Examples.m

@@ -129,6 +129,16 @@ typedef struct s_ {
   return array;
 }
 
+- (NSArray*)nullableMethodCheckedForNullAndReturnOkay {
+  NSObject* nullableObject = [self nullableMethod];
+  NSArray* array;
+  if (nullableObject == nil) {
+    return array;
+  }
+  array = @[ nullableObject ]; // does not report here
+  return array;
+}
+
 - (NSArray*)secondElementNullableObjectInNSArrayBad {
   NSObject* allocatedObject = [NSObject alloc];
   NSObject* nullableObject = [self nullableMethod];