From 7a434adea83a4dbd74a8a832b4bfd4eac6aa4f6d Mon Sep 17 00:00:00 2001
From: Ryan Rhee <ryanrhee@fb.com>
Date: Mon, 26 Sep 2016 08:39:35 -0700
Subject: [PATCH] [componentkit][const] Whitelist certain classes

Reviewed By: martinoluca

Differential Revision: D3911399

fbshipit-source-id: c523779
---
 infer/src/clang/ComponentKit.ml                 | 17 ++++++++++++++++-
 .../componentkit/FakeComponentKitHeader.h       | 15 +++++++++++++++
 .../objcpp/linters/componentkit/Test.mm         |  7 +++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/infer/src/clang/ComponentKit.ml b/infer/src/clang/ComponentKit.ml
index 05ac2d16e..42c96b10f 100644
--- a/infer/src/clang/ComponentKit.ml
+++ b/infer/src/clang/ComponentKit.ml
@@ -74,6 +74,20 @@ and contains_ck_impl decl_list =
     const NSString *y;
     ``` *)
 let mutable_local_vars_advice context decl =
+  let rec get_referenced_type (qual_type: Clang_ast_t.qual_type) : Clang_ast_t.decl option =
+    let typ_opt = Ast_utils.get_desugared_type qual_type.qt_type_ptr in
+    match (typ_opt : Clang_ast_t.c_type option) with
+    | Some RecordType (_, decl_ptr) -> Ast_utils.get_decl decl_ptr
+    | Some LValueReferenceType (_, inner_qual_type) -> get_referenced_type inner_qual_type
+    | _ -> None in
+
+  let is_of_whitelisted_type qual_type =
+    let whitelist = ["CKComponentScope"; "FBTrackingNodeScope"; "FBTrackingCodeScope"] in
+    match get_referenced_type qual_type with
+    | Some CXXRecordDecl (_, ndi, _, _, _, _, _, _) ->
+        IList.mem string_equal ndi.ni_name whitelist
+    | _ -> false in
+
   match decl with
   | Clang_ast_t.VarDecl(decl_info, _, qual_type, _) ->
       let is_const_ref = match Ast_utils.get_type qual_type.qt_type_ptr with
@@ -85,7 +99,8 @@ let mutable_local_vars_advice context decl =
                       && Ast_utils.is_in_main_file decl
                       && General_utils.is_objc_extension
                       && (not (Ast_utils.is_syntactically_global_var decl))
-                      && (not is_const) in
+                      && (not is_const)
+                      && not (is_of_whitelisted_type qual_type) in
       if condition then
         Some {
           CIssue.issue = CIssue.Mutable_local_variable_in_component_file;
diff --git a/infer/tests/codetoanalyze/objcpp/linters/componentkit/FakeComponentKitHeader.h b/infer/tests/codetoanalyze/objcpp/linters/componentkit/FakeComponentKitHeader.h
index e43200079..9785cd334 100644
--- a/infer/tests/codetoanalyze/objcpp/linters/componentkit/FakeComponentKitHeader.h
+++ b/infer/tests/codetoanalyze/objcpp/linters/componentkit/FakeComponentKitHeader.h
@@ -24,3 +24,18 @@ typedef struct { NSString* string; } LabelAttributes;
 typedef struct { int thisStructIsEmpty; } ViewAttributes;
 
 typedef struct { int thisStructIsEmpty; } CKSize;
+
+// Mimic importing CKComponentScope
+
+class CKComponentScope {
+ public:
+  CKComponentScope(Class __unsafe_unretained componentClass,
+                   id identifier = nil,
+                   id (^initialStateCreator)(void) = nil);
+  ~CKComponentScope();
+  int a;
+
+ private:
+  CKComponentScope(const CKComponentScope&) = delete;
+  CKComponentScope& operator=(const CKComponentScope&) = delete;
+};
diff --git a/infer/tests/codetoanalyze/objcpp/linters/componentkit/Test.mm b/infer/tests/codetoanalyze/objcpp/linters/componentkit/Test.mm
index b6d021afe..98d602e03 100644
--- a/infer/tests/codetoanalyze/objcpp/linters/componentkit/Test.mm
+++ b/infer/tests/codetoanalyze/objcpp/linters/componentkit/Test.mm
@@ -86,5 +86,12 @@ class BarClass {
   const BarClass& s2 = s1; // no error
   BarClass& s3 = s1; // error
   const BarClass s4 = {.a = 3}; // no error
+
+  // Whitelisted C++ class
+  CKComponentScope w1(self); // no error
+  const CKComponentScope& w2 = w1; // no error
+  CKComponentScope& w3 = w1; // no error
+  // const CKComponentScope w4 = {.a = 3}; // Can't, lacks default ctor
+  const CKComponentScope w4(self); // no error
 }
 @end