[linters] Restrict the remove observer check to when target ios sdk version is greater or equal than 9.0

Reviewed By: ddino

Differential Revision: D5670652

fbshipit-source-id: bb26abf

infer/lib/linter_rules/linters.al

@@ -124,7 +124,8 @@ DEFINE-CHECKER REGISTERED_OBSERVER_BEING_DEALLOCATED = {
 
   SET report_when =
 			WHEN
-	    	NOT (eventually_addObserver IMPLIES eventually_removeObserver)
+	    	NOT (eventually_addObserver IMPLIES eventually_removeObserver) AND
+				NOT iphoneos_target_sdk_version_greater_or_equal("9.0") //this is not needed after iOS SDK 9.0
 			HOLDS-IN-NODE ObjCImplementationDecl, ObjCProtocolDecl;
 
 	SET message =

infer/src/clang/cPredicates.ml

@@ -505,6 +505,13 @@ let iphoneos_target_sdk_version_by_path (cxt: CLintersContext.context) =
   | None (* no version by path specified, use default version *)
    -> Config.iphoneos_target_sdk_version
 
+let iphoneos_target_sdk_version_greater_or_equal (cxt: CLintersContext.context) version =
+  match iphoneos_target_sdk_version_by_path cxt with
+  | Some target_version
+   -> Utils.compare_versions target_version version >= 0
+  | None
+   -> false
+
 let decl_unavailable_in_supported_ios_sdk (cxt: CLintersContext.context) an =
   let config_iphoneos_target_sdk_version = iphoneos_target_sdk_version_by_path cxt in
   let allowed_os_versions =

infer/src/clang/cPredicates.mli

@@ -122,4 +122,6 @@ val has_visibility_attribute : Ctl_parser_types.ast_node -> ALVar.alexp -> bool
 
 val has_used_attribute : Ctl_parser_types.ast_node -> bool
 
+val iphoneos_target_sdk_version_greater_or_equal : CLintersContext.context -> string -> bool
+
 val within_available_class_block : CLintersContext.context -> Ctl_parser_types.ast_node -> bool

infer/src/clang/cTL.ml

@@ -830,6 +830,8 @@ let rec eval_Atomic _pred_name args an lcxt =
    -> CPredicates.is_strong_property an
   | "is_unop_with_kind", [kind], an
    -> CPredicates.is_unop_with_kind an kind
+  | "iphoneos_target_sdk_version_greater_or_equal", [version], _
+   -> CPredicates.iphoneos_target_sdk_version_greater_or_equal lcxt (ALVar.alexp_to_string version)
   | "method_return_type", [typ], an
    -> CPredicates.method_return_type an typ
   | "within_responds_to_selector_block", [], an

infer/tests/codetoanalyze/objc/ioslints/Makefile

@@ -19,6 +19,7 @@ ANALYZER = linters
 INFER_OPTIONS = --no-filtering --debug-exceptions --project-root $(TESTS_DIR) \
 --iphoneos-target-sdk-version 8.0 \
 --iphoneos-target-sdk-version-path-regex "codetoanalyze/objc/ioslints/filter_out_unavailable_api\.m:10.0" \
+--iphoneos-target-sdk-version-path-regex "codetoanalyze/objc/ioslints/RemoveObserverInGivenSDKTest\.m:9.0" \
 --no-keep-going
 INFERPRINT_OPTIONS = --issues-tests
 

infer/tests/codetoanalyze/objc/ioslints/RemoveObserverInGivenSDKTest.m

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2016 - 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/Foundation.h>
+
+@interface RemoveObserverInGivenSDKTest2 : NSObject
+
+@property(strong) NSNotificationCenter* nc;
+
+@end
+
+@implementation RemoveObserverInGivenSDKTest2
+
+- (void)foo:(NSMutableDictionary*)dict {
+  self.nc = [NSNotificationCenter defaultCenter];
+  [self.nc addObserver:self selector:@selector(foo:) name:nil object:nil];
+}
+
+@end