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fix: use a dispatchqueue to synchronize setting and getting userConfig #254

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Merged
merged 1 commit into from
Aug 28, 2025
Merged

fix: use a dispatchqueue to synchronize setting and getting userConfig #254

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4 changes: 4 additions & 0 deletions DevCycle.xcodeproj/project.pbxproj
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@
52A48707278C9BE200DABA34 /* Log.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52A48706278C9BE200DABA34 /* Log.swift */; };
52A96990279F3AAA00D3A602 /* PlatformDetails.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52A9698F279F3AAA00D3A602 /* PlatformDetails.swift */; };
52A96A0F27A0A7CF00D3A602 /* EventQueue.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52A96A0E27A0A7CF00D3A602 /* EventQueue.swift */; };
52D342B72E60A47700B86328 /* DVCConfigTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52D342B62E60A47300B86328 /* DVCConfigTests.swift */; };
52E693EA27567E2600B52375 /* DevCycleService.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52E693E927567E2600B52375 /* DevCycleService.swift */; };
52E693ED2756816A00B52375 /* DVCConfig.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52E693EC2756816A00B52375 /* DVCConfig.swift */; };
52E693F62758032500B52375 /* DevCycleServiceTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 52E693F52758032500B52375 /* DevCycleServiceTests.swift */; };
Expand Down Expand Up @@ -125,6 +126,7 @@
52A48706278C9BE200DABA34 /* Log.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Log.swift; sourceTree = "<group>"; };
52A9698F279F3AAA00D3A602 /* PlatformDetails.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PlatformDetails.swift; sourceTree = "<group>"; };
52A96A0E27A0A7CF00D3A602 /* EventQueue.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EventQueue.swift; sourceTree = "<group>"; };
52D342B62E60A47300B86328 /* DVCConfigTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DVCConfigTests.swift; sourceTree = "<group>"; };
52E693E927567E2600B52375 /* DevCycleService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DevCycleService.swift; sourceTree = "<group>"; };
52E693EC2756816A00B52375 /* DVCConfig.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DVCConfig.swift; sourceTree = "<group>"; };
52E693F52758032500B52375 /* DevCycleServiceTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DevCycleServiceTests.swift; sourceTree = "<group>"; };
Expand Down Expand Up @@ -203,6 +205,7 @@
5264A78C2768E87C00FEDB43 /* Models */ = {
isa = PBXGroup;
children = (
52D342B62E60A47300B86328 /* DVCConfigTests.swift */,
52E8C1F02DF87C560044783D /* DevCycleEventTests.swift */,
5268DB68275020D900D17A40 /* DevCycleUserTest.swift */,
524F4E61276D20A500CB9069 /* DVCVariableTests.swift */,
Expand Down Expand Up @@ -480,6 +483,7 @@
52A1139F27AB235C000B8285 /* EventQueueTests.swift in Sources */,
52133B2428DE0FEB0007691D /* GetTestConfig.swift in Sources */,
5256A99A2798716400E749FF /* ObjCDevCycleClientTests.m in Sources */,
52D342B72E60A47700B86328 /* DVCConfigTests.swift in Sources */,
5256A99B2798716400E749FF /* ObjcDevCycleUserTests.m in Sources */,
524F4E62276D20A600CB9069 /* DVCVariableTests.swift in Sources */,
);
Expand Down
24 changes: 12 additions & 12 deletions DevCycle/DevCycleClient.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -158,7 +158,7 @@ public class DevCycleClient {
Log.error("Error getting config: \(error)", tags: ["setup"])

// If network failed but we have a cached config, don't return error
if self.config?.userConfig != nil {
if self.config?.getUserConfig() != nil {
Log.info("Using cached config due to network error")
finalError = nil
}
Expand Down Expand Up @@ -245,7 +245,7 @@ public class DevCycleClient {

private func updateUserConfig(_ config: UserConfig) {
let oldSSEURL = self.config?.userConfig?.sse?.url
self.config?.userConfig = config
self.config?.setUserConfig(config: config)

let newSSEURL = config.sse?.url
if newSSEURL != nil && oldSSEURL != newSSEURL {
Expand All @@ -260,7 +260,7 @@ public class DevCycleClient {
return
}

guard let sseURL = self.config?.userConfig?.sse?.url else {
guard let sseURL = self.config?.getUserConfig()?.sse?.url else {
Log.error("No SSE URL in config")
return
}
Expand All @@ -275,7 +275,7 @@ public class DevCycleClient {
self.sseConnection = nil
}

if let inactivityDelay = self.config?.userConfig?.sse?.inactivityDelay {
if let inactivityDelay = self.config?.getUserConfig()?.sse?.inactivityDelay {
self.inactivityDelayMS = Double(inactivityDelay)
}
self.sseConnection = SSEConnection(
Expand All @@ -297,7 +297,7 @@ public class DevCycleClient {
}
let sseMessage = try SSEMessage(from: messageDictionary)
if sseMessage.data.type == nil || sseMessage.data.type == "refetchConfig" {
if self?.config?.userConfig?.etag == nil
if self?.config?.getUserConfig()?.etag == nil
|| sseMessage.data.etag != self?.config?.userConfig?.etag
{
self?.refetchConfig(
Expand Down Expand Up @@ -395,7 +395,7 @@ public class DevCycleClient {
{
variable = variableFromDictionary
} else {
if let config = self.config?.userConfig,
if let config = self.config?.getUserConfig(),
let variableFromApi = config.variables[key]
{
variable = DVCVariable(from: variableFromApi, defaultValue: defaultValue)
Expand Down Expand Up @@ -462,12 +462,12 @@ public class DevCycleClient {

// Try to use cached config for the new user
// If we have a cached config, proceed without error
if self.useCachedConfigForUser(user: updateUser), self.config?.userConfig != nil {
if self.useCachedConfigForUser(user: updateUser), self.config?.getUserConfig() != nil {
Log.info(
"Using cached config for identifyUser due to network error: \(error)",
tags: ["identify"])
self.user = user
callback?(nil, self.config?.userConfig?.variables)
callback?(nil, self.config?.getUserConfig()?.variables)
return
} else {
// No cached config available, return error and don't change client state
Expand All @@ -482,7 +482,7 @@ public class DevCycleClient {
Log.debug("IdentifyUser config: \(config)", tags: ["identify"])
self.updateUserConfig(config)
self.user = user
callback?(nil, self.config?.userConfig?.variables)
callback?(nil, self.config?.getUserConfig()?.variables)
} else {
Log.error("No config returned for identifyUser", tags: ["identify"])
callback?(ClientError.ConfigFetchFailed, nil)
Expand Down Expand Up @@ -564,11 +564,11 @@ public class DevCycleClient {
}

public func allFeatures() -> [String: Feature] {
return self.config?.userConfig?.features ?? [:]
return self.config?.getUserConfig()?.features ?? [:]
}

public func allVariables() -> [String: Variable] {
return self.config?.userConfig?.variables ?? [:]
return self.config?.getUserConfig()?.variables ?? [:]
}

public func track(_ event: DevCycleEvent) {
Expand Down Expand Up @@ -738,7 +738,7 @@ public class DevCycleClient {
if options?.disableConfigCache != true,
let cachedConfig = cacheService.getConfig(user: user)
{
self.config?.userConfig = cachedConfig
self.config?.setUserConfig(config: cachedConfig)
Log.debug("Loaded config from cache for user_id \(String(describing: user.userId))")
return true
}
Expand Down
33 changes: 25 additions & 8 deletions DevCycle/Models/DVCConfig.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -9,9 +9,31 @@ import Foundation
public class DVCConfig {
var sdkKey: String
var user: DevCycleUser
var userConfig: UserConfig? {
didSet {
if let userConfig = self.userConfig {
private let userConfigQueue = DispatchQueue(label: "com.devcycle.userConfigQueue")
var userConfig: UserConfig?

init(sdkKey: String, user: DevCycleUser) {
self.sdkKey = sdkKey
self.user = user
}

func getUserConfig() -> UserConfig? {
return userConfigQueue.sync {
return self.userConfig
}
}

func setUserConfig(config: UserConfig?) {
var configToNotify: UserConfig?

userConfigQueue.sync {
self.userConfig = config
configToNotify = config
}

// Post notification outside of the lock to avoid potential deadlocks
if let userConfig = configToNotify {
DispatchQueue.main.async {
NotificationCenter.default.post(
name: Notification.Name(NotificationNames.NewUserConfig),
object: self,
Expand All @@ -20,9 +42,4 @@ public class DVCConfig {
}
}
}

init(sdkKey: String, user: DevCycleUser) {
self.sdkKey = sdkKey
self.user = user
}
}
197 changes: 197 additions & 0 deletions DevCycleTests/Models/DVCConfigTests.swift
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Original file line number Diff line number Diff line change
@@ -0,0 +1,197 @@
//
// DVCConfigTests.swift
// DevCycleTests
//
//

import XCTest
@testable import DevCycle

final class DVCConfigTests: XCTestCase {

var mockUser: DevCycleUser!

override func setUp() {
super.setUp()
mockUser = try! DevCycleUser.builder()
.userId("test-user")
.isAnonymous(false)
.build()
}

override func tearDown() {
mockUser = nil
super.tearDown()
}

func getMockUserConfig(config: String = "test_config_eval_reason") throws -> UserConfig {
let data = getConfigData(name: config)
let dictionary = try JSONSerialization.jsonObject(with: data, options: .fragmentsAllowed) as! [String:Any]
return try UserConfig(from: dictionary)
}

func testConcurrentConfigAccess() throws {
let testConfig = DVCConfig(sdkKey: "test-sdk-key", user: mockUser)

let expectation = XCTestExpectation(description: "Concurrent config access completed")
expectation.expectedFulfillmentCount = 100 // 50 reads + 50 writes

let concurrentQueue = DispatchQueue(label: "test.concurrent", attributes: .concurrent)

// Test concurrent reads
for _ in 0..<50 {
concurrentQueue.async {
let _ = testConfig.getUserConfig()
expectation.fulfill()
}
}

let evalConfig = try self.getMockUserConfig(config: "test_config_eval_reason")

// Test concurrent writes
for _ in 0..<50 {
concurrentQueue.async {
testConfig.setUserConfig(config: evalConfig)
expectation.fulfill()
}
}

wait(for: [expectation], timeout: 10.0)

// Verify the final state is consistent
let finalConfig = testConfig.getUserConfig()
XCTAssertNotNil(finalConfig)
}

func testConcurrentConfigAccessWithVariables() throws {
let testConfig = DVCConfig(sdkKey: "test-sdk-key", user: mockUser)
let mockUserConfig = try getMockUserConfig()
testConfig.setUserConfig(config: mockUserConfig)

let expectation = XCTestExpectation(description: "Concurrent variable access completed")
expectation.expectedFulfillmentCount = 200 // 100 reads + 100 writes

let concurrentQueue = DispatchQueue(label: "test.concurrent.variables", attributes: .concurrent)

// Test concurrent reads of variables
for _ in 0..<100 {
concurrentQueue.async {
let variables = testConfig.getUserConfig()?.variables
XCTAssertNotNil(variables)
expectation.fulfill()
}
}
let evalConfig = try self.getMockUserConfig(config: "test_config_eval_reason")

// Test concurrent writes with new configs
for _ in 0..<100 {
concurrentQueue.async {
testConfig.setUserConfig(config: evalConfig)
expectation.fulfill()
}
}

wait(for: [expectation], timeout: 10.0)

// Verify final state
let finalConfig = testConfig.getUserConfig()
XCTAssertNotNil(finalConfig)
XCTAssertNotNil(finalConfig?.variables)
}

func testRapidConfigUpdates() throws {
let testConfig = DVCConfig(sdkKey: "test-sdk-key", user: mockUser)

let expectation = XCTestExpectation(description: "Rapid config updates completed")
expectation.expectedFulfillmentCount = 1000

let concurrentQueue = DispatchQueue(label: "test.rapid", attributes: .concurrent)
let evalConfig = try self.getMockUserConfig(config: "test_config_eval_reason")

// Rapidly update config from multiple threads
for _ in 0..<1000 {
concurrentQueue.async {
testConfig.setUserConfig(config: evalConfig)
expectation.fulfill()
}
}

wait(for: [expectation], timeout: 10.0)

// Verify no crashes occurred
let finalConfig = testConfig.getUserConfig()
XCTAssertNotNil(finalConfig)
}

func testConfigAccessDuringUpdates() throws {

let testConfig = DVCConfig(sdkKey: "test-sdk-key", user: mockUser)
testConfig.setUserConfig(config: try self.getMockUserConfig())

let expectation = XCTestExpectation(description: "Config access during updates completed")
expectation.expectedFulfillmentCount = 500 // 250 updates + 250 reads

let updateQueue = DispatchQueue(label: "test.updates", attributes: .concurrent)
let readQueue = DispatchQueue(label: "test.reads", attributes: .concurrent)

let evalConfig = try self.getMockUserConfig(config: "test_config_eval_reason")

// Continuously update config
for _ in 0..<250 {
updateQueue.async {
testConfig.setUserConfig(config: evalConfig)
expectation.fulfill()
}
}

// Continuously read config while updates are happening
for _ in 0..<250 {
readQueue.async {
let config = testConfig.getUserConfig()
_ = config?.variables
_ = config?.features
XCTAssertNotNil(config)
expectation.fulfill()
}
}

wait(for: [expectation], timeout: 10.0)

// Verify final state
let finalConfig = testConfig.getUserConfig()
XCTAssertNotNil(finalConfig)
}

func testSetConfigNil() throws {
let testNilConfig = DVCConfig(sdkKey: "test-sdk-key", user: mockUser)
testNilConfig.setUserConfig(config: try self.getMockUserConfig())

let expectation = XCTestExpectation(description: "Config access during setting config to nil completed")
expectation.expectedFulfillmentCount = 500 // 250 updates + 250 reads

let updateQueue = DispatchQueue(label: "test.updates", attributes: .concurrent)
let readQueue = DispatchQueue(label: "test.reads", attributes: .concurrent)

let evalConfig = try self.getMockUserConfig(config: "test_config_eval_reason")

// Continuously update config
for i in 0..<250 {
updateQueue.async {
testNilConfig.setUserConfig(config: i % 2 == 0 ? evalConfig : nil)
expectation.fulfill()
}
}

// Continuously read config while updates are happening
for _ in 0..<250 {
readQueue.async {
let config = testNilConfig.getUserConfig()
_ = config?.variables
_ = config?.features
expectation.fulfill()
}
}

wait(for: [expectation], timeout: 10.0)
}
}
2 changes: 1 addition & 1 deletion DevCycleTests/Models/DevCycleClientTests.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -165,7 +165,7 @@ class DevCycleClientTest: XCTestCase {
client.close(callback: nil)
}

func testFlushEventsWithEvalReasons() throws{
func testFlushEventsWithEvalReasons() throws {
let data = getConfigData(name: "test_config_eval_reason")
let dictionary = try JSONSerialization.jsonObject(with: data, options: .fragmentsAllowed) as! [String:Any]
let evalReasonConfig = try UserConfig(from: dictionary)
Expand Down
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