From 634a42b61931f8d4c4a9f4acccd52f9ac3f3e769 Mon Sep 17 00:00:00 2001
From: Dulma Churchill <dulmarod@fb.com>
Date: Tue, 3 Mar 2020 10:11:58 -0800
Subject: [PATCH] [SelfInBlock] Take ns_noescape into account when reporting
 captured strong self.

Summary: When reporting CapturedStrongSelf we shouldn't report it when the block is "no escaping", as this won't lead to a retain cycle, so capturing strongSelf is ok.

Reviewed By: jvillard

Differential Revision: D20224359

fbshipit-source-id: c60dae333
---
 infer/src/checkers/SelfInBlock.ml             |  9 +++++---
 .../objc/self-in-block/StrongSelf.m           | 23 ++++++++++++++++++-
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/infer/src/checkers/SelfInBlock.ml b/infer/src/checkers/SelfInBlock.ml
index 1d61f1fe4..383611b95 100644
--- a/infer/src/checkers/SelfInBlock.ml
+++ b/infer/src/checkers/SelfInBlock.ml
@@ -471,9 +471,12 @@ let report_weakself_multiple_issue summary domain (weakSelf1 : DomainData.t)
   Reporting.log_error summary ~ltr ~loc:weakSelf1.loc IssueType.multiple_weakself message
 
 
-let report_captured_strongself_issue domain summary (capturedStrongSelf : DomainData.t)
+let report_captured_strongself_issue domain summary attributes (capturedStrongSelf : DomainData.t)
     report_captured_strongself =
-  if not (Pvar.Set.mem capturedStrongSelf.pvar report_captured_strongself) then (
+  if
+    Option.is_none attributes.ProcAttributes.passed_as_noescape_block_to
+    && not (Pvar.Set.mem capturedStrongSelf.pvar report_captured_strongself)
+  then (
     let report_captured_strongself =
       Pvar.Set.add capturedStrongSelf.pvar report_captured_strongself
     in
@@ -496,7 +499,7 @@ let report_issues summary domain attributes =
     match domain_data.kind with
     | DomainData.CAPTURED_STRONG_SELF ->
         let reported_captured_strong_self =
-          report_captured_strongself_issue domain summary domain_data
+          report_captured_strongself_issue domain summary attributes domain_data
             result.reported_captured_strong_self
         in
         {result with reported_captured_strong_self}
diff --git a/infer/tests/codetoanalyze/objc/self-in-block/StrongSelf.m b/infer/tests/codetoanalyze/objc/self-in-block/StrongSelf.m
index 61b65f7ec..91e4471a0 100644
--- a/infer/tests/codetoanalyze/objc/self-in-block/StrongSelf.m
+++ b/infer/tests/codetoanalyze/objc/self-in-block/StrongSelf.m
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-#include <Foundation/NSObject.h>
+#include <Foundation/Foundation.h>
 
 @class SelfInBlockTest;
 
@@ -31,6 +31,8 @@
 
 - (void)bar;
 
+- (A*)process:(A*)obj;
+
 @end
 
 void m(SelfInBlockTest* obj) {}
@@ -47,6 +49,10 @@ void m2(_Nullable SelfInBlockTest* obj) {}
 - (void)bar {
 }
 
+- (A*)process:(A*)obj {
+  return obj;
+}
+
 - (void)mixSelfWeakSelf_bad {
   __weak __typeof(self) weakSelf = self;
   int (^my_block)() = ^() {
@@ -218,6 +224,21 @@ void m2(_Nullable SelfInBlockTest* obj) {}
   };
 }
 
+- (void)capturedStrongSelf_good:(NSArray<A*>*)allResults {
+  __weak __typeof(self) weakSelf = self;
+  int (^my_block)() = ^() {
+    __strong typeof(self) strongSelf = weakSelf;
+    if (strongSelf) {
+      [allResults
+          enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL* stop) {
+            A* result =
+                [strongSelf process:obj]; // no bug because of NS_NOESCAPE flag
+          }];
+    }
+    return 0;
+  };
+}
+
 - (void)mixSelfWeakSelf_good:(NSArray*)resources {
   __weak __typeof(self) weakSelf = self;
   int (^my_block)() = ^() {