[retain cycles] Fix false positives to do with not finding weak attribute in the tenv

Reviewed By: mbouaziz

Differential Revision: D7067081

fbshipit-source-id: 2722867

infer/src/backend/RetainCycles.ml

@@ -63,11 +63,11 @@ let edge_is_strong tenv obj_edge =
             let find fields =
               List.find ~f:equal_fn fields |> Option.value_map ~f:trd3 ~default:[]
             in
-            find fields @ find statics
+            Some (find fields @ find statics)
         | None ->
-            [] )
+            None )
     | _ ->
-        []
+        None
   in
   let has_weak_or_unretained_or_assign params =
     List.exists
@@ -76,14 +76,18 @@ let edge_is_strong tenv obj_edge =
         || String.equal Config.assign att )
       params
   in
-  let ia = get_item_annotation obj_edge.rc_from.rc_node_typ obj_edge.rc_field.rc_field_name in
   let weak_edge =
+    match get_item_annotation obj_edge.rc_from.rc_node_typ obj_edge.rc_field.rc_field_name with
+    | Some ia ->
         List.exists
           ~f:(fun ((ann: Annot.t), _) ->
             ( String.equal ann.class_name Config.property_attributes
             || String.equal ann.class_name Config.ivar_attributes )
             && has_weak_or_unretained_or_assign ann.parameters )
           ia
+    | None ->
+        true
+    (* Assume the edge is weak if the type cannot be found in the tenv, to avoid FPs *)
   in
   not weak_edge
 

infer/tests/build_systems/codetoanalyze/objc_retain_cycles/Caller.m

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2018 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#import "ViewController.h"
+#import <Foundation/NSObject.h>
+
+int main() {
+  ViewController* controller = [ViewController new];
+  return 0;
+}

infer/tests/build_systems/codetoanalyze/objc_retain_cycles/View.h

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2018 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#import <Foundation/NSObject.h>
+
+@interface View : NSObject
+
+@property(nonatomic, weak) id delegate;
+
+@end

infer/tests/build_systems/codetoanalyze/objc_retain_cycles/View.m

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2018 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#import "View.h"
+
+@implementation View
+
+@end

infer/tests/build_systems/codetoanalyze/objc_retain_cycles/ViewController.h

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2018 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#import <Foundation/NSObject.h>
+
+@interface ViewController : NSObject
+
+@end

infer/tests/build_systems/codetoanalyze/objc_retain_cycles/ViewController.m

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2018 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#import "ViewController.h"
+
+@implementation ViewController {
+  View* _hostingView;
+}
+
+- (instancetype)init {
+  if (self = [super init]) {
+    _hostingView = [[View alloc] init];
+    _hostingView.delegate = self;
+  }
+
+  return self;
+}
+
+@end

infer/tests/build_systems/objc_retain_cycles/Makefile

@@ -0,0 +1,23 @@
+# Copyright (c) 2017 - present Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+TESTS_DIR = ../..
+ROOT_DIR = $(TESTS_DIR)/../..
+CODETOANALYZE_DIR = ../codetoanalyze/objc_retain_cycles
+
+ANALYZER = checkers
+SOURCES = $(CODETOANALYZE_DIR)/View.m $(CODETOANALYZE_DIR)/ViewController.m $(CODETOANALYZE_DIR)/Caller.m
+OBJECTS = $(CODETOANALYZE_DIR)/View.o $(CODETOANALYZE_DIR)/ViewController.o $(CODETOANALYZE_DIR)/Caller.o
+INFER_OPTIONS = --biabduction-only --report-custom-error --developer-mode --project-root $(TESTS_DIR)
+INFERPRINT_OPTIONS = --project-root $(TESTS_DIR) --issues-tests
+
+include $(TESTS_DIR)/infer.make
+
+infer-out/report.json: $(CLANG_DEPS) $(SOURCES) $(MAKEFILE_LIST)
+	$(QUIET)$(REMOVE_DIR) buck-out && \
+	$(call silent_on_success,Testing analysis with Objective-C getters and setters,\
+	$(INFER_BIN) $(INFER_OPTIONS) --results-dir $(CURDIR)/infer-out -- clang -c  -fobjc-arc $(SOURCES))