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Add sync mechanism to prevent background crashes and fix ndb reopen order

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This adds a sync mechanism in Ndb.swift to coordinate certain usage of
nostrdb.c calls and the need to close nostrdb due to app lifecycle
requirements. Furthermore, it fixes the order of operations when
re-opening NostrDB, to avoid race conditions where a query uses an older
Ndb generation.

This sync mechanism allows multiple queries to happen simultaneously
(from the Swift-side), while preventing ndb from simultaneously closing
during such usages. It also does that while keeping the Ndb interface
sync and nonisolated, which keeps the API easy to use from
Swift/SwiftUI and allows for parallel operations to occur.

If Swift Actors were to be used (e.g. creating an NdbActor), the Ndb.swift
interface would change in such a way that it would propagate the need for
several changes throughout the codebase, including loading logic in
some ViewModels. Furthermore, it would likely decrease performance by
forcing Ndb.swift operations to run sequentially when they could run in
parallel.

Changelog-Fixed: Fixed crashes that happened when the app went into background mode
Closes: https://github.com/damus-io/damus/issues/3245
Signed-off-by: Daniel D’Aquino <daniel@daquino.me>
This commit is contained in:
Daniel D’Aquino
2025-11-12 16:04:47 -08:00
parent 6d9107f662
commit 20dc672dbf
59 changed files with 790 additions and 416 deletions
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1
damusTests/Mocking/MockDamusState.swift
View File

@@ -10,6 +10,7 @@ import Foundation
import EmojiPicker
// Generates a test damus state with configurable mock parameters
@MainActor
func generate_test_damus_state(
mock_profile_info: [Pubkey: Profile]?,
home: HomeModel? = nil,

72
damusTests/NostrNetworkManagerTests/AppLifecycleHandlingTests.swift Normal file
View File

@@ -0,0 +1,72 @@
//
// AppLifecycleHandlingTests.swift
// damus
//
// Created by Daniel D’Aquino on 2025-11-06.
//
import XCTest
@testable import damus
class AppLifecycleHandlingTests: XCTestCase {
func getTestNotesJSONL() -> String {
// Get the path for the test_notes.jsonl file in the same folder as this test file
let testBundle = Bundle(for: type(of: self))
let fileURL = testBundle.url(forResource: "test_notes", withExtension: "jsonl")!
// Load the contents of the file
return try! String(contentsOf: fileURL, encoding: .utf8)
}
/// Tests for some race conditions between the app closing down and streams opening throughout the app
/// See https://github.com/damus-io/damus/issues/3245 for more context.
///
/// **Note:** Time delays are intentionally added because we actually want to provoke possible race conditions,
/// so using proper waiting mechanisms would defeat the purpose of the test.
func testAppLifecycleRaceConditions() async throws {
let damusState = await generate_test_damus_state(mock_profile_info: nil)
let notesJSONL = getTestNotesJSONL()
for noteText in notesJSONL.split(separator: "\n") {
let _ = damusState.ndb.processEvent("[\"EVENT\",\"subid\",\(String(noteText))]")
}
// Give some time ndb some time to fill up
try? await Task.sleep(for: .milliseconds(2000))
// Start measuring the time elapsed for debugging
let startTime = CFAbsoluteTimeGetCurrent()
func getElapsedTimeMiliseconds() -> String {
return "\((CFAbsoluteTimeGetCurrent() - startTime) * 1000) ms"
}
Task.detached {
for i in 0...10000 {
try await Task.sleep(for: .milliseconds(Int.random(in: 0...10)))
print("APP_LIFECYCLE_TEST \(i): About to close Ndb. Elapsed time: \(getElapsedTimeMiliseconds())")
damusState.ndb.close()
print("APP_LIFECYCLE_TEST \(i): Closed Ndb. Elapsed time: \(getElapsedTimeMiliseconds())")
print("APP_LIFECYCLE_TEST \(i): Reopening Ndb. Elapsed time: \(getElapsedTimeMiliseconds())")
_ = damusState.ndb.reopen()
print("APP_LIFECYCLE_TEST \(i): Reopened Ndb. Elapsed time: \(getElapsedTimeMiliseconds())")
}
}
for i in 0...10000 {
do {
try await Task.sleep(for: .milliseconds(Int.random(in: 0...10)))
print("APP_LIFECYCLE_TEST \(i): Starting new query. Elapsed time: \(getElapsedTimeMiliseconds())")
_ = try damusState.ndb.query(filters: [try NdbFilter(from: NostrFilter(kinds: [.text], limit: 1000))], maxResults: 500)
}
catch {
print("APP_LIFECYCLE_TEST \(i): Query error: \(error). Elapsed time: \(getElapsedTimeMiliseconds())")
}
print("APP_LIFECYCLE_TEST \(i): Finished query. Elapsed time: \(getElapsedTimeMiliseconds())")
}
}
}

3
damusTests/NostrNetworkManagerTests/NostrNetworkManagerTests.swift
View File

@@ -9,6 +9,7 @@ import XCTest
@testable import damus
@MainActor
class NostrNetworkManagerTests: XCTestCase {
var damusState: DamusState? = nil
@@ -137,7 +138,7 @@ class NostrNetworkManagerTests: XCTestCase {
switch item {
case .event(let noteKey):
// Lookup the note to verify it exists
if let note = ndb.lookup_note_by_key_and_copy(noteKey) {
if let note = try? ndb.lookup_note_by_key_and_copy(noteKey) {
count += 1
receivedIds.insert(note.id)
}

4
damusTests/NostrNetworkManagerTests/ProfilesManagerTests.swift
View File

@@ -42,7 +42,7 @@ class ProfilesManagerTests: XCTestCase {
try await Task.sleep(for: .milliseconds(100))
// Verify profile is in NDB
let cachedProfile = ndb.lookup_profile_and_copy(profilePubkey)
let cachedProfile = try? ndb.lookup_profile_and_copy(profilePubkey)
XCTAssertNotNil(cachedProfile, "Profile should be cached in NDB")
XCTAssertEqual(cachedProfile?.name, "testuser")
@@ -109,7 +109,7 @@ class ProfilesManagerTests: XCTestCase {
try await Task.sleep(for: .milliseconds(100))
// Verify profile is in NDB
let cachedProfile = ndb.lookup_profile_and_copy(profilePubkey)
let cachedProfile = try? ndb.lookup_profile_and_copy(profilePubkey)
XCTAssertNotNil(cachedProfile, "Profile should be cached in NDB")
// Create ProfilesManager

17
damusTests/NostrNetworkManagerTests/ThreadModelTests.swift
View File

@@ -9,6 +9,7 @@
import XCTest
@testable import damus
@MainActor
final class ThreadModelTests: XCTestCase {
var damusState: DamusState? = nil
@@ -39,8 +40,12 @@ final class ThreadModelTests: XCTestCase {
/// Tests loading up a thread and checking if the repost count loads as expected.
func testActionBarModel() async throws {
try! await damusState?.nostrNetwork.userRelayList.set(userRelayList: NIP65.RelayList())
await damusState?.nostrNetwork.connect()
guard let damusState else {
XCTFail("DamusState is nil, test is misconfigured")
return
}
try! await damusState.nostrNetwork.userRelayList.set(userRelayList: NIP65.RelayList())
await damusState.nostrNetwork.connect()
let testNoteJson = """
{"content":"https://smartflowsocial.s3.us-east-1.amazonaws.com/clients/cm7kdrwdk0000qyu6fwtd96ui/0cab65a9-0142-48e3-abd7-94d20e30d3b2.jpg\n\n","pubkey":"71ecabd8b6b33548e075ff01b31568ffda19d0ac2788067d99328c6de4885975","tags":[["t","meme"],["t","memes"],["t","memestr"],["t","plebchain"]],"created_at":1755694800,"id":"64b26d0a587f5f894470e1e4783756b4d8ba971226de975ee30ac1b69970d5a1","kind":1,"sig":"c000794da8c4f7549b546630b16ed17f6edc0af0269b8c46ce14f5b1937431e7575b78351bc152007ebab5720028e5fe4b738f99e8887f273d35dd2217d1cc3d"}
@@ -48,12 +53,12 @@ final class ThreadModelTests: XCTestCase {
let testShouldComplete = XCTestExpectation(description: "Test should complete")
Task {
let note = NostrEvent.owned_from_json(json: testNoteJson)!
let threadModel = await ThreadModel(event: note, damus_state: damusState!)
await threadModel.subscribe()
let actionBarModel = make_actionbar_model(ev: note.id, damus: damusState!)
let threadModel = ThreadModel(event: note, damus_state: damusState)
threadModel.subscribe()
let actionBarModel = make_actionbar_model(ev: note.id, damus: damusState)
while true {
try await Task.sleep(nanoseconds: 500_000_000)
await actionBarModel.update(damus: damusState!, evid: note.id)
await actionBarModel.update(damus: damusState, evid: note.id)
if actionBarModel.boosts >= 5 {
break
}