Dip
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AliSoftware
Thread safety question
Hi,
enable thread sanitiser in Xcode.
I used the sample app provided and added this code. in application didFinishLaunchingWithOptions after the configure function.
DispatchQueue.global(qos: .userInteractive).async {
_ = try! self.container.resolve() as PersonProviderAPI
}
i am getting the error below
(lldb) thread info -s
thread #1: tid = 0xb5feba, 0x000000010846d210 libclang_rt.tsan_iossim_dynamic.dylib`__tsan_on_report, queue = 'com.apple.main-thread', stop reason = Data race detected
{
"all_addresses_are_same" : true,
"description" : "Data race",
"instrumentation_class" : "ThreadSanitizer",
"is_swift_access_race" : false,
"issue_type" : "data-race",
"location_description" : "Location is a 144-byte heap object at 0x7b24000196b0",
"locs" : [
{
"address" : 0,
"file_descriptor" : 0,
"index" : 0,
"object_type" : "",
"size" : 144,
"start" : 135394549143216,
"suppressable" : 0,
"thread_id" : 1,
"trace" : [
4433745643,
4518380009,
4432193247,
4432193580,
4480071751,
4547030401
],
"type" : "heap"
}
],
"memory_address" : 135394549143240,
"mops" : [
{
"address" : 135394549143240,
"index" : 0,
"is_atomic" : false,
"is_write" : true,
"size" : 8,
"thread_id" : 1,
"trace" : [
4455414645,
4455417239,
4455399549,
4455413244,
4455496011,
4455490104,
4455489180,
4455488196,
4432186403,
4432192140,
4480034918,
4547030401
]
},
{
"address" : 135394549143240,
"index" : 1,
"is_atomic" : false,
"is_write" : false,
"size" : 8,
"thread_id" : 3,
"trace" : [
4455495051,
4455490104,
4455489180,
4455488196,
4432190235,
4432190546,
4432190881,
4433864684,
4546520124
]
}
],
"mutexes" : [
{
"address" : 135360189314752,
"destroyed" : 0,
"index" : 0,
"mutex_id" : 1138,
"trace" : [
4433615524,
4456469052,
4455387904,
4455395834,
4455395015,
4432193247,
4432193580,
4480071751,
4547030401
]
}
],
"report_count" : 0,
"sleep_trace" : [
],
"stacks" : [
],
"stop_description" : "Data race detected",
"summary" : "Data race in closure #1 () throws -> A in Dip.DependencyContainer.inContext<A>(key: Dip.DefinitionKey, injectedInType: Swift.Optional<Any.Type>, injectedInProperty: Swift.Optional<Swift.String>, inCollaboration: Swift.Bool, container: Swift.Optional<Dip.DependencyContainer>, logErrors: Swift.Optional<Swift.Bool>, block: () throws -> A) throws -> A at 0x7b24000196b0",
"tag" : 0,
"threads" : [
{
"index" : 0,
"name" : "",
"parent_thread_id" : 1,
"running" : 1,
"thread_id" : 1,
"thread_os_id" : 11927226,
"trace" : [
]
},
{
"index" : 1,
"name" : "",
"parent_thread_id" : 0,
"running" : 1,
"thread_id" : 3,
"thread_os_id" : 11927348,
"trace" : [
]
}
],
"unique_tids" : [
]
}
file:///Users/or84489/ws/Dip/Sources/Dip.swift: runtime: Threading Issues: Data race in closure #1 () throws -> A in Dip.DependencyContainer.inContext<A>(key: Dip.DefinitionKey, injectedInType: Swift.Optional<Any.Type>, injectedInProperty: Swift.Optional<Swift.String>, inCollaboration: Swift.Bool, container: Swift.Optional<Dip.DependencyContainer>, logErrors: Swift.Optional<Swift.Bool>, block: () throws -> A) throws -> A at 0x7b24000196b0
notice: Threading Issues: Location is a 144-byte heap object at 0x7b24000196b0
Write of size 8 by thread 1
#0 0x0000000109903b75 in closure #1 in DependencyContainer.inContext<A>(key:injectedInType:injectedInProperty:inCollaboration:container:logErrors:block:) at /Users/or84489/ws/Dip/Sources/Dip.swift:233
#1 0x0000000109904597 in partial apply for closure #1 in DependencyContainer.inContext<A>(key:injectedInType:injectedInProperty:inCollaboration:container:logErrors:block:) ()
#2 0x000000010990007d in DependencyContainer.threadSafe<A>(_:) at /Users/or84489/ws/Dip/Sources/Dip.swift:109
#3 0x00000001099035fc in DependencyContainer.inContext<A>(key:injectedInType:injectedInProperty:inCollaboration:container:logErrors:block:) at /Users/or84489/ws/Dip/Sources/Dip.swift:208
#4 0x000000010991794b in DependencyContainer._resolve(type:tag:builder:) at /Users/or84489/ws/Dip/Sources/Resolve.swift:141
#5 0x0000000109916238 in DependencyContainer.resolve(_:tag:builder:) at /Users/or84489/ws/Dip/Sources/Resolve.swift:123
#6 0x0000000109915e9c in DependencyContainer._resolve<A>(tag:builder:) at /Users/or84489/ws/Dip/Sources/Resolve.swift:131
#7 0x0000000109915ac4 in DependencyContainer.resolve<A>(tag:) at /Users/or84489/ws/Dip/Sources/Resolve.swift:50
#8 0x00000001082dcc23 in AppDelegate.application(_:didFinishLaunchingWithOptions:) at /Users/or84489/ws/Dip/SampleApp/DipSampleApp/AppDelegate.swift:31
#9 0x00000001082de28c in @objc AppDelegate.application(_:didFinishLaunchingWithOptions:) ()
#10 0x000000010b07e866 in -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] ()
#11 0x000000010f062d81 in start ()
Read of size 8 by thread 3
#0 0x000000010991758b in DependencyContainer._resolve(type:tag:builder:) at /Users/or84489/ws/Dip/Sources/Resolve.swift:141
#1 0x0000000109916238 in DependencyContainer.resolve(_:tag:builder:) at /Users/or84489/ws/Dip/Sources/Resolve.swift:123
#2 0x0000000109915e9c in DependencyContainer._resolve<A>(tag:builder:) at /Users/or84489/ws/Dip/Sources/Resolve.swift:131
#3 0x0000000109915ac4 in DependencyContainer.resolve<A>(tag:) at /Users/or84489/ws/Dip/Sources/Resolve.swift:50
#4 0x00000001082ddb1b in closure #1 in AppDelegate.application(_:didFinishLaunchingWithOptions:) at /Users/or84489/ws/Dip/SampleApp/DipSampleApp/AppDelegate.swift:28
#5 0x00000001082ddc52 in partial apply for closure #1 in AppDelegate.application(_:didFinishLaunchingWithOptions:) ()
#6 0x00000001082ddda1 in thunk for @escaping @callee_guaranteed () -> () ()
#7 0x00000001084767ec in __tsan::invoke_and_release_block(void*) ()
#8 0x000000010efe643c in _dispatch_client_callout ()
Heap block allocated by thread 1
#0 0x00000001084596eb in wrap_malloc ()
#1 0x000000010d5101e9 in swift_slowAlloc ()
#2 0x00000001082de6df in AppDelegate.init() at /Users/or84489/ws/Dip/SampleApp/DipSampleApp/AppDelegate.swift:17
#3 0x00000001082de82c in @objc AppDelegate.init() ()
#4 0x000000010b087847 in _UIApplicationMainPreparations ()
#5 0x000000010f062d81 in start ()
Mutex M1138 created
#0 0x0000000108439aa4 in wrap_pthread_mutex_init ()
#1 0x0000000109a0523c in -[NSRecursiveLock init] ()
#2 0x00000001098fd300 in NSRecursiveLock.__allocating_init() ()
#3 0x00000001098ff1fa in DependencyContainer.init(autoInjectProperties:configBlock:) at /Users/or84489/ws/Dip/Sources/Dip.swift:46
#4 0x00000001098feec7 in DependencyContainer.__allocating_init(autoInjectProperties:configBlock:) ()
#5 0x00000001082de6df in AppDelegate.init() at /Users/or84489/ws/Dip/SampleApp/DipSampleApp/AppDelegate.swift:17
#6 0x00000001082de82c in @objc AppDelegate.init() ()
#7 0x000000010b087847 in _UIApplicationMainPreparations ()
#8 0x000000010f062d81 in start ()
please advise
I've never used Thread Sanitizer before so can't say why it gives such a warning. I'd suggest playing with a minimum code snippet that would use a recursive lock and recursive function calls if you are curious. It might be just a sanitizer not playing well with recursive locks.
i do think there is a race condition here.
the inContext function is protected by the lock, but also setting the context object.
context = Context(
key: key,
injectedInType: injectedInType,
injectedInProperty: injectedInProperty,
inCollaboration: inCollaboration
)
the line at Resolve.swift ~ 141
return try inContext(key:key, injectedInType: context?.resolvingType) {
is not protected by a lock and it is access the context object which is not protected.
i think we need to protect the access to context?.resolvingType
making the change below fix this issue, but i am not sure if this is the correct fix.
| =>git diff
diff --git a/Sources/Resolve.swift b/Sources/Resolve.swift
index 4cf0791..b84e8ca 100644
--- a/Sources/Resolve.swift
+++ b/Sources/Resolve.swift
@@ -46,7 +46,9 @@ extension DependencyContainer {
- seealso: `register(_:type:tag:factory:)`
*/
public func resolve<T>(tag: DependencyTagConvertible? = nil) throws -> T {
- return try _resolve(tag: tag) { (factory: () throws -> T) in try factory() }
+ return try threadSafe {
+ return try _resolve(tag: tag) { (factory: () throws -> T) in try factory() }
+ }
}
/**