From df1063b9eb396ebf40c2035fe95ba648bef8701e Mon Sep 17 00:00:00 2001
From: Dulma Churchill <dulmarod@fb.com>
Date: Tue, 22 Aug 2017 07:37:36 -0700
Subject: [PATCH] [linters] Adding example of checking a parameter for empty
 struct

Reviewed By: jvillard

Differential Revision: D5678330

fbshipit-source-id: 3d1891f
---
 .../TestParamterLabelsChecks.mm               |  1 +
 .../objcpp/linters-for-test-only/issues.exp   |  9 +++++----
 .../linters-for-test-only/linters_example.al  | 20 +++++++++++++++++++
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/infer/tests/codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm b/infer/tests/codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm
index d38096964..8ca291856 100644
--- a/infer/tests/codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm
+++ b/infer/tests/codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm
@@ -25,6 +25,7 @@ struct SomeStruct {
 
 SomeButton* buttonComponent(void);
 SomeButton* buttonComponent(void) {
+  // flagging passing empty struct
   return [SomeButton newWithStruct:{} map:{} object:nil number:0];
 };
 
diff --git a/infer/tests/codetoanalyze/objcpp/linters-for-test-only/issues.exp b/infer/tests/codetoanalyze/objcpp/linters-for-test-only/issues.exp
index f5090a1d3..84f328065 100644
--- a/infer/tests/codetoanalyze/objcpp/linters-for-test-only/issues.exp
+++ b/infer/tests/codetoanalyze/objcpp/linters-for-test-only/issues.exp
@@ -4,7 +4,8 @@ codetoanalyze/objcpp/linters-for-test-only/ReferenceTest.mm, ReferenceTest_newWi
 codetoanalyze/objcpp/linters-for-test-only/ReferenceTest.mm, ReferenceTest_newWithActionRef:, 40, TEST_REFERENCE, []
 codetoanalyze/objcpp/linters-for-test-only/ReferenceTest.mm, ReferenceTest_newWithConstAction:, 21, TEST_REFERENCE, []
 codetoanalyze/objcpp/linters-for-test-only/ReferenceTest.mm, ReferenceTest_newWithConstAction:, 36, TEST_REFERENCE, []
-codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, anotherButtonComponent, 33, TEST_PARAMETER_LABEL, []
-codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, anotherButtonComponent, 33, TEST_PARAMETER_LABEL_REGEXP, []
-codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 28, TEST_PARAMETER_LABEL, []
-codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 28, TEST_PARAMETER_LABEL_REGEXP, []
+codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, anotherButtonComponent, 34, TEST_PARAMETER_LABEL, []
+codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, anotherButtonComponent, 34, TEST_PARAMETER_LABEL_REGEXP, []
+codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 29, TEST_PARAMETER_LABEL, []
+codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 29, TEST_PARAMETER_LABEL_EMPTY_STRUCT, []
+codetoanalyze/objcpp/linters-for-test-only/TestParamterLabelsChecks.mm, buttonComponent, 29, TEST_PARAMETER_LABEL_REGEXP, []
diff --git a/infer/tests/codetoanalyze/objcpp/linters-for-test-only/linters_example.al b/infer/tests/codetoanalyze/objcpp/linters-for-test-only/linters_example.al
index d3f291b3c..5f9b11ec9 100644
--- a/infer/tests/codetoanalyze/objcpp/linters-for-test-only/linters_example.al
+++ b/infer/tests/codetoanalyze/objcpp/linters-for-test-only/linters_example.al
@@ -35,3 +35,23 @@ DEFINE-CHECKER TEST_PARAMETER_LABEL_REGEXP = {
       HOLDS-IN-NODE ObjCMessageExpr;
   SET message = "Found method with parameter labeled with `number` and with type `int`";
 };
+
+DEFINE-CHECKER TEST_PARAMETER_LABEL_EMPTY_STRUCT = {
+  LET is_empty_init_list =
+    WHEN ((is_node("ImplicitValueInitExpr")) HOLDS-EVERYWHERE-NEXT)
+     HOLDS-IN-NODE InitListExpr;
+  LET is_empty_struct =
+    WHEN ((is_empty_init_list) HOLDS-EVERYWHERE-NEXT)
+  	 HOLDS-IN-NODE CXXBindTemporaryExpr;
+  LET method_has_parameter_type =
+        WHEN
+          HOLDS-NEXT WITH-TRANSITION ParameterName "newWithStruct"
+            (is_empty_struct)
+          HOLDS-IN-NODE ObjCMessageExpr;
+  SET report_when =
+      WHEN
+         method_has_parameter_type
+         AND call_method(REGEXP("^new.*:$"))
+      HOLDS-IN-NODE ObjCMessageExpr;
+  SET message = "Do not pass empty struct to the parameter `newWithStruct` of method `new...`";
+};