Retry confirmed private media after reconnect

2026-07-26 08:25:19 +00:00 · 2026-07-25 23:49:41 +02:00
parent 00df1b0e1d
commit ae8a401986
9 changed files with 1806 additions and 13 deletions
@@ -95,10 +95,20 @@ private final class MockChatMediaTransferContext: ChatMediaTransferContext {
        transferId: String
    )] = []
    private(set) var privateFileLegacyAllowances: [Bool] = []
+    private(set) var privateFileReceiptRetryTransferIDs: [String] = []
    private(set) var broadcastFileSends: [String] = []
    private(set) var cancelledTransfers: [String] = []
+    private(set) var privateMediaPolicyResolutionRequests: [PeerID] = []
    var privateMediaPolicy: PrivateMediaSendPolicy = .encrypted
    var resolvedPrivateMediaPolicy: PrivateMediaSendPolicy?
+    var resolvesPrivateMediaPolicyImmediately = true
+    var supportsAuthenticatedPrivateMediaReceipts = false
+    var authenticatedPrivateMediaReceiptGeneration = UUID(
+        uuidString: "00000000-0000-0000-0000-000000000001"
+    )!
+    private var pendingPrivateMediaPolicyResolutions: [
+        @MainActor (PrivateMediaSendPolicy) -> Void
+    ] = []
    private(set) var legacyConsentRequests: [(
        id: UUID,
        peerID: PeerID,
@@ -113,11 +123,40 @@ private final class MockChatMediaTransferContext: ChatMediaTransferContext {
        privateMediaPolicy
    }

+    func authenticatedPrivateMediaReceiptSessionGeneration(
+        to peerID: PeerID
+    ) -> UUID? {
+        supportsAuthenticatedPrivateMediaReceipts
+            ? authenticatedPrivateMediaReceiptGeneration
+            : nil
+    }
+
    func resolvePrivateMediaSendPolicy(
        to peerID: PeerID,
        completion: @escaping @MainActor (PrivateMediaSendPolicy) -> Void
    ) {
-        completion(resolvedPrivateMediaPolicy ?? privateMediaPolicy)
+        privateMediaPolicyResolutionRequests.append(peerID)
+        if resolvesPrivateMediaPolicyImmediately {
+            completion(resolvedPrivateMediaPolicy ?? privateMediaPolicy)
+        } else {
+            pendingPrivateMediaPolicyResolutions.append(completion)
+        }
+    }
+
+    var pendingPrivateMediaPolicyResolutionCount: Int {
+        pendingPrivateMediaPolicyResolutions.count
+    }
+
+    func resolveNextPrivateMediaPolicy(
+        _ policy: PrivateMediaSendPolicy? = nil
+    ) {
+        guard !pendingPrivateMediaPolicyResolutions.isEmpty else { return }
+        let completion = pendingPrivateMediaPolicyResolutions.removeFirst()
+        completion(
+            policy
+                ?? resolvedPrivateMediaPolicy
+                ?? privateMediaPolicy
+        )
    }

    func requestLegacyPrivateMediaConsent(
@@ -162,6 +201,16 @@ private final class MockChatMediaTransferContext: ChatMediaTransferContext {
        privateFileLegacyAllowances.append(allowLegacyFallback)
    }

+    func sendFilePrivateReceiptRetry(
+        _ packet: BitchatFilePacket,
+        to peerID: PeerID,
+        transferId: String
+    ) {
+        privateFileSends.append((packet, peerID, transferId))
+        privateFileLegacyAllowances.append(false)
+        privateFileReceiptRetryTransferIDs.append(transferId)
+    }
+
    func sendFileBroadcast(_ packet: BitchatFilePacket, transferId: String) {
        broadcastFileSends.append(transferId)
    }
@@ -851,6 +900,548 @@ struct ChatMediaTransferCoordinatorContextTests {
        #expect(context.legacyConsentRequests.isEmpty)
        #expect(context.privateFileSends.isEmpty)
    }
+
+    @Test @MainActor
+    func receiptCapableEncryptedMediaRetriesExactPacketAfterReconnect() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "1122334455667788")
+        context.selectedPrivateChatPeer = peerID
+        context.supportsAuthenticatedPrivateMediaReceipts = true
+        let fileName = "voice_0011223344556677.m4a"
+        let preparer = StaticVoiceNotePreparer(fileName: fileName)
+        let transferIDs = DeterministicMediaTransferIDFactory()
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                try preparer.prepare(url)
+            },
+            transferIDFactory: transferIDs.make
+        )
+        let url = try makeCoordinatorVoiceURL(fileName: fileName)
+        defer {
+            try? FileManager.default.removeItem(
+                at: url.deletingLastPathComponent()
+            )
+        }
+
+        coordinator.sendVoiceNote(at: url)
+        #expect(await TestHelpers.waitUntil(
+            { context.privateFileSends.count == 1 },
+            timeout: TestConstants.longTimeout
+        ))
+        let messageID = try #require(
+            context.privateChats[peerID]?.first?.id
+        )
+        let initial = try #require(
+            context.privateFileSends.first
+        )
+        #expect(PrivateMediaMessageIdentity.isStableID(messageID))
+        #expect(coordinator.retainedReconnectRetryCount == 1)
+
+        coordinator.handleTransferEvent(.completed(
+            id: initial.transferId,
+            totalFragments: 1
+        ))
+        #expect(coordinator.retainedReconnectRetryCount == 1)
+        #expect(context.deliveryStatusUpdates.last?.status == .sent)
+
+        coordinator.peerDidReconnect(peerID)
+        #expect(context.privateFileSends.count == 2)
+        let retry = try #require(context.privateFileSends.last)
+        #expect(retry.packet.encode() == initial.packet.encode())
+        #expect(retry.peerID == peerID)
+        #expect(retry.transferId != initial.transferId)
+        #expect(context.privateFileReceiptRetryTransferIDs == [
+            retry.transferId
+        ])
+        #expect(context.privateFileLegacyAllowances == [false, false])
+
+        coordinator.confirmPrivateMediaDelivery(messageID: messageID)
+        #expect(coordinator.retainedReconnectRetryCount == 0)
+        #expect(context.cancelledTransfers == [retry.transferId])
+        #expect(context.removedMessages.isEmpty)
+        #expect(!context.deliveryStatusUpdates.contains {
+            if case .failed = $0.status { return true }
+            return false
+        })
+
+        // Receipt confirmation removes retry ownership before transport
+        // cancellation, so its late callback cannot delete the delivered row
+        // or re-arm another reconnect retry.
+        coordinator.handleTransferEvent(.cancelled(
+            id: retry.transferId,
+            sentFragments: 1,
+            totalFragments: 2
+        ))
+        coordinator.peerDidReconnect(peerID)
+        #expect(context.privateFileSends.count == 2)
+        #expect(context.removedMessages.isEmpty)
+        #expect(coordinator.messageIDToTransferId[messageID] == nil)
+    }
+
+    @Test @MainActor
+    func bit8OnlyEncryptedMediaNeverRetainsOrAutomaticallyRetries() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "1122334455667788")
+        context.selectedPrivateChatPeer = peerID
+        context.privateMediaPolicy = .encrypted
+        context.supportsAuthenticatedPrivateMediaReceipts = false
+        let fileName = "voice_1111222233334444.m4a"
+        let preparer = StaticVoiceNotePreparer(fileName: fileName)
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                try preparer.prepare(url)
+            }
+        )
+        let url = try makeCoordinatorVoiceURL(fileName: fileName)
+        defer {
+            try? FileManager.default.removeItem(
+                at: url.deletingLastPathComponent()
+            )
+        }
+
+        coordinator.sendVoiceNote(at: url)
+        #expect(await TestHelpers.waitUntil(
+            { context.privateFileSends.count == 1 },
+            timeout: TestConstants.longTimeout
+        ))
+        let initial = try #require(context.privateFileSends.first)
+        coordinator.handleTransferEvent(.completed(
+            id: initial.transferId,
+            totalFragments: 1
+        ))
+        coordinator.peerDidReconnect(peerID)
+        coordinator.peerDidAuthenticate(peerID)
+
+        #expect(coordinator.retainedReconnectRetryCount == 0)
+        #expect(context.privateFileSends.count == 1)
+        #expect(context.privateFileReceiptRetryTransferIDs.isEmpty)
+        #expect(context.privateMediaPolicyResolutionRequests.isEmpty)
+    }
+
+    @Test @MainActor
+    func consentedRawLegacyMediaNeverEntersAutomaticRetry() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "1122334455667788")
+        context.selectedPrivateChatPeer = peerID
+        context.privateMediaPolicy = .legacyRequiresConsent
+        // Even a contradictory stale bit-9 observation must not retain an
+        // invocation that actually selected the explicit raw path.
+        context.supportsAuthenticatedPrivateMediaReceipts = true
+        let fileName = "voice_2222333344445555.m4a"
+        let preparer = StaticVoiceNotePreparer(fileName: fileName)
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                try preparer.prepare(url)
+            }
+        )
+        let url = try makeCoordinatorVoiceURL(fileName: fileName)
+        defer {
+            try? FileManager.default.removeItem(
+                at: url.deletingLastPathComponent()
+            )
+        }
+
+        coordinator.sendVoiceNote(at: url)
+        #expect(await TestHelpers.waitUntil(
+            { context.legacyConsentRequests.count == 1 },
+            timeout: TestConstants.longTimeout
+        ))
+        context.resolveNextLegacyConsent(true)
+        let initial = try #require(context.privateFileSends.first)
+        #expect(context.privateFileLegacyAllowances == [true])
+        #expect(coordinator.retainedReconnectRetryCount == 0)
+
+        coordinator.handleTransferEvent(.completed(
+            id: initial.transferId,
+            totalFragments: 1
+        ))
+        context.privateMediaPolicy = .encrypted
+        coordinator.peerDidReconnect(peerID)
+        coordinator.peerDidAuthenticate(peerID)
+
+        #expect(context.privateFileSends.count == 1)
+        #expect(context.privateFileReceiptRetryTransferIDs.isEmpty)
+        #expect(coordinator.retainedReconnectRetryCount == 0)
+    }
+
+    @Test @MainActor
+    func authenticatedGenerationSupersedesStaleReconnectResolution() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "1122334455667788")
+        context.selectedPrivateChatPeer = peerID
+        context.supportsAuthenticatedPrivateMediaReceipts = true
+        context.resolvesPrivateMediaPolicyImmediately = false
+        let oldGeneration = context
+            .authenticatedPrivateMediaReceiptGeneration
+        let newGeneration = UUID(
+            uuidString: "00000000-0000-0000-0000-000000000002"
+        )!
+        let fileName = "voice_3333444455556666.m4a"
+        let preparer = StaticVoiceNotePreparer(fileName: fileName)
+        let transferIDs = DeterministicMediaTransferIDFactory()
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                try preparer.prepare(url)
+            },
+            transferIDFactory: transferIDs.make
+        )
+        let url = try makeCoordinatorVoiceURL(fileName: fileName)
+        defer {
+            try? FileManager.default.removeItem(
+                at: url.deletingLastPathComponent()
+            )
+        }
+
+        coordinator.sendVoiceNote(at: url)
+        #expect(await TestHelpers.waitUntil(
+            { context.privateFileSends.count == 1 },
+            timeout: TestConstants.longTimeout
+        ))
+        let initial = try #require(context.privateFileSends.first)
+        coordinator.peerDidReconnect(peerID)
+        #expect(context.pendingPrivateMediaPolicyResolutionCount == 1)
+
+        context.authenticatedPrivateMediaReceiptGeneration = newGeneration
+        coordinator.peerDidAuthenticate(peerID)
+        #expect(context.pendingPrivateMediaPolicyResolutionCount == 2)
+
+        // The old-generation completion lost ownership and is inert.
+        context.resolveNextPrivateMediaPolicy(.encrypted)
+        #expect(context.privateFileReceiptRetryTransferIDs.isEmpty)
+        #expect(context.cancelledTransfers.isEmpty)
+
+        context.resolveNextPrivateMediaPolicy(.encrypted)
+        #expect(context.cancelledTransfers == [initial.transferId])
+        #expect(context.privateFileReceiptRetryTransferIDs.count == 1)
+        #expect(
+            context.authenticatedPrivateMediaReceiptGeneration
+                == newGeneration
+        )
+        #expect(oldGeneration != newGeneration)
+    }
+
+    @Test @MainActor
+    func panicClearsRetainedRetryPendingResolutionAndExpiry() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "1122334455667788")
+        context.selectedPrivateChatPeer = peerID
+        context.supportsAuthenticatedPrivateMediaReceipts = true
+        context.resolvesPrivateMediaPolicyImmediately = false
+        let fileName = "voice_3333444455556666.m4a"
+        let preparer = StaticVoiceNotePreparer(fileName: fileName)
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                try preparer.prepare(url)
+            },
+            reconnectRetryLimits: PrivateMediaReconnectRetryLimits(
+                maxRetainedPackets: 1,
+                maxRetainedBytes: 1_024,
+                maxRetriesPerMessage: 1,
+                retentionSeconds: 0.1,
+                maxRetriesPerReconnect: 1
+            )
+        )
+        let url = try makeCoordinatorVoiceURL(fileName: fileName)
+        defer {
+            try? FileManager.default.removeItem(
+                at: url.deletingLastPathComponent()
+            )
+        }
+
+        coordinator.sendVoiceNote(at: url)
+        #expect(await TestHelpers.waitUntil(
+            { context.privateFileSends.count == 1 },
+            timeout: TestConstants.longTimeout
+        ))
+        let initial = try #require(context.privateFileSends.first)
+        coordinator.handleTransferEvent(.completed(
+            id: initial.transferId,
+            totalFragments: 1
+        ))
+        #expect(coordinator.retainedReconnectRetryCount == 1)
+
+        coordinator.peerDidReconnect(peerID)
+        #expect(context.pendingPrivateMediaPolicyResolutionCount == 1)
+        let failedBeforePanic = context.deliveryStatusUpdates.filter {
+            if case .failed = $0.status { return true }
+            return false
+        }.count
+
+        coordinator.resetForPanic()
+        context.resolveNextPrivateMediaPolicy(.encrypted)
+        try await Task.sleep(nanoseconds: 250_000_000)
+        coordinator._test_expireReconnectRetries()
+
+        #expect(coordinator.retainedReconnectRetryCount == 0)
+        #expect(coordinator.retainedReconnectRetryBytes == 0)
+        #expect(coordinator.transferIdToMessageIDs.isEmpty)
+        #expect(coordinator.messageIDToTransferId.isEmpty)
+        #expect(context.privateFileSends.count == 1)
+        #expect(context.privateFileReceiptRetryTransferIDs.isEmpty)
+        #expect(context.deliveryStatusUpdates.filter {
+            if case .failed = $0.status { return true }
+            return false
+        }.count == failedBeforePanic)
+    }
+
+    @Test @MainActor
+    func retryCountAndRetentionTimeEndInVisibleFailure() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "1122334455667788")
+        context.selectedPrivateChatPeer = peerID
+        context.supportsAuthenticatedPrivateMediaReceipts = true
+        let clock = MutableMediaRetryClock(
+            Date(timeIntervalSince1970: 4_000)
+        )
+        let limits = PrivateMediaReconnectRetryLimits(
+            maxRetainedPackets: 2,
+            maxRetainedBytes: 1_024,
+            maxRetriesPerMessage: 1,
+            retentionSeconds: 10,
+            maxRetriesPerReconnect: 1
+        )
+        let fileName = "voice_4444555566667777.m4a"
+        let preparer = StaticVoiceNotePreparer(fileName: fileName)
+        let transferIDs = DeterministicMediaTransferIDFactory()
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                try preparer.prepare(url)
+            },
+            reconnectRetryLimits: limits,
+            now: clock.now,
+            transferIDFactory: transferIDs.make
+        )
+        let url = try makeCoordinatorVoiceURL(fileName: fileName)
+        defer {
+            try? FileManager.default.removeItem(
+                at: url.deletingLastPathComponent()
+            )
+        }
+
+        coordinator.sendVoiceNote(at: url)
+        #expect(await TestHelpers.waitUntil(
+            { context.privateFileSends.count == 1 },
+            timeout: TestConstants.longTimeout
+        ))
+        let initial = try #require(context.privateFileSends.first)
+        coordinator.handleTransferEvent(.completed(
+            id: initial.transferId,
+            totalFragments: 1
+        ))
+        coordinator.peerDidReconnect(peerID)
+        let retryID = try #require(
+            context.privateFileReceiptRetryTransferIDs.first
+        )
+        coordinator.handleTransferEvent(.cancelled(
+            id: retryID,
+            sentFragments: 0,
+            totalFragments: 1
+        ))
+
+        #expect(coordinator.retainedReconnectRetryCount == 0)
+        #expect(context.removedMessages.isEmpty)
+        #expect(context.deliveryStatusUpdates.contains {
+            $0.messageID.hasPrefix("media-")
+                && $0.status == .failed(reason: String(
+                    localized: "content.delivery.reason.not_delivered",
+                    defaultValue: "Not delivered",
+                    comment: "Failure reason shown when a private media transfer could not finish"
+                ))
+        })
+
+        // A separate retained row that locally completed but never received a
+        // remote receipt expires to a distinct visible failure.
+        let ttlFileName = "voice_5555666677778888.m4a"
+        let ttlPreparer = StaticVoiceNotePreparer(
+            fileName: ttlFileName
+        )
+        let ttlCoordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                try ttlPreparer.prepare(url)
+            },
+            reconnectRetryLimits: limits,
+            now: clock.now,
+            transferIDFactory: transferIDs.make
+        )
+        let ttlURL = try makeCoordinatorVoiceURL(
+            fileName: ttlFileName
+        )
+        defer {
+            try? FileManager.default.removeItem(
+                at: ttlURL.deletingLastPathComponent()
+            )
+        }
+        let sendsBeforeTTL = context.privateFileSends.count
+        ttlCoordinator.sendVoiceNote(at: ttlURL)
+        #expect(await TestHelpers.waitUntil(
+            {
+                context.privateFileSends.count
+                    == sendsBeforeTTL + 1
+            },
+            timeout: TestConstants.longTimeout
+        ))
+        let ttlInitial = try #require(context.privateFileSends.last)
+        ttlCoordinator.handleTransferEvent(.completed(
+            id: ttlInitial.transferId,
+            totalFragments: 1
+        ))
+        clock.advance(by: 10)
+        ttlCoordinator._test_expireReconnectRetries()
+
+        #expect(ttlCoordinator.retainedReconnectRetryCount == 0)
+        #expect(context.deliveryStatusUpdates.contains {
+            $0.status == .failed(
+                reason: String(
+                    localized:
+                        "content.delivery.reason.private_media_delivery_unconfirmed",
+                    defaultValue: "Delivery could not be confirmed"
+                )
+            )
+        })
+    }
+
+    @Test @MainActor
+    func retentionAndPerReconnectWorkAreBounded() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "1122334455667788")
+        context.selectedPrivateChatPeer = peerID
+        context.supportsAuthenticatedPrivateMediaReceipts = true
+        let limits = PrivateMediaReconnectRetryLimits(
+            maxRetainedPackets: 2,
+            maxRetainedBytes: 10,
+            maxRetriesPerMessage: 2,
+            retentionSeconds: 120,
+            maxRetriesPerReconnect: 1
+        )
+        let transferIDs = DeterministicMediaTransferIDFactory()
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                let content = Data("voice".utf8)
+                return BitchatFilePacket(
+                    fileName: url.lastPathComponent,
+                    fileSize: UInt64(content.count),
+                    mimeType: "audio/mp4",
+                    content: content
+                )
+            },
+            reconnectRetryLimits: limits,
+            transferIDFactory: transferIDs.make
+        )
+        let fileNames = [
+            "voice_6666777788889999.m4a",
+            "voice_777788889999aaaa.m4a",
+            "voice_88889999aaaabbbb.m4a"
+        ]
+        var roots: [URL] = []
+        defer {
+            for root in roots {
+                try? FileManager.default.removeItem(at: root)
+            }
+        }
+
+        for fileName in fileNames {
+            let url = try makeCoordinatorVoiceURL(
+                fileName: fileName,
+                bytes: Data("voice".utf8)
+            )
+            roots.append(url.deletingLastPathComponent())
+            // The production preparer preserves this stable filename.
+            coordinator.sendVoiceNote(at: url)
+        }
+        #expect(await TestHelpers.waitUntil(
+            { context.privateFileSends.count == 3 },
+            timeout: TestConstants.longTimeout
+        ))
+        #expect(coordinator.retainedReconnectRetryCount == 2)
+        #expect(coordinator.retainedReconnectRetryBytes <= 10)
+
+        for send in context.privateFileSends {
+            coordinator.handleTransferEvent(.completed(
+                id: send.transferId,
+                totalFragments: 1
+            ))
+        }
+        coordinator.peerDidReconnect(peerID)
+        #expect(context.privateFileReceiptRetryTransferIDs.count == 1)
+    }
+
+    @Test @MainActor
+    func userCancellationReleasesRetainedBytesAndIgnoresLateEvent() async throws {
+        let context = MockChatMediaTransferContext()
+        let peerID = PeerID(str: "1122334455667788")
+        context.selectedPrivateChatPeer = peerID
+        context.supportsAuthenticatedPrivateMediaReceipts = true
+        let fileName = "voice_9999aaaabbbbcccc.m4a"
+        let preparer = StaticVoiceNotePreparer(fileName: fileName)
+        let coordinator = ChatMediaTransferCoordinator(
+            context: context,
+            prepareVoiceNotePacket: { url in
+                try preparer.prepare(url)
+            }
+        )
+        let url = try makeCoordinatorVoiceURL(fileName: fileName)
+        defer {
+            try? FileManager.default.removeItem(
+                at: url.deletingLastPathComponent()
+            )
+        }
+
+        coordinator.sendVoiceNote(at: url)
+        #expect(await TestHelpers.waitUntil(
+            { context.privateFileSends.count == 1 },
+            timeout: TestConstants.longTimeout
+        ))
+        let messageID = try #require(
+            context.privateChats[peerID]?.first?.id
+        )
+        let transferID = try #require(
+            context.privateFileSends.first?.transferId
+        )
+
+        coordinator.cancelMediaSend(messageID: messageID)
+        coordinator.handleTransferEvent(.cancelled(
+            id: transferID,
+            sentFragments: 0,
+            totalFragments: 1
+        ))
+
+        #expect(coordinator.retainedReconnectRetryCount == 0)
+        #expect(coordinator.retainedReconnectRetryBytes == 0)
+        #expect(context.cancelledTransfers == [transferID])
+        #expect(context.removedMessages.map(\.messageID) == [
+            messageID
+        ])
+        #expect(!context.deliveryStatusUpdates.contains {
+            if case .failed = $0.status { return true }
+            return false
+        })
+    }
+}
+
+private func makeCoordinatorVoiceURL(
+    fileName: String,
+    bytes: Data = Data("voice".utf8)
+) throws -> URL {
+    let directory = FileManager.default.temporaryDirectory
+        .appendingPathComponent(
+            "media-retry-\(UUID().uuidString)",
+            isDirectory: true
+        )
+    try FileManager.default.createDirectory(
+        at: directory,
+        withIntermediateDirectories: true
+    )
+    let url = directory.appendingPathComponent(fileName)
+    try bytes.write(to: url)
+    return url
 }

 private final class PausedImagePreparer: @unchecked Sendable {
@@ -97,6 +97,7 @@ private final class MockChatVerificationContext: ChatVerificationContext {
    var noiseSessionKeysByPeerID: [PeerID: Data] = [:]
    private(set) var installedCallbacks: (onPeerAuthenticated: (PeerID, String) -> Void, onHandshakeRequired: (PeerID) -> Void)?
    private(set) var triggeredHandshakes: [PeerID] = []
+    private(set) var privateMediaAuthenticatedPeers: [PeerID] = []
    private(set) var sentChallenges: [(peerID: PeerID, noiseKeyHex: String, nonceA: Data)] = []
    private(set) var sentResponses: [(peerID: PeerID, noiseKeyHex: String, nonceA: Data)] = []

@@ -113,6 +114,9 @@ private final class MockChatVerificationContext: ChatVerificationContext {
        establishedNoiseSessions.contains(peerID)
    }
    func triggerHandshake(with peerID: PeerID) { triggeredHandshakes.append(peerID) }
+    func privateMediaPeerDidAuthenticate(_ peerID: PeerID) {
+        privateMediaAuthenticatedPeers.append(peerID)
+    }

    func sendVerifyChallenge(to peerID: PeerID, noiseKeyHex: String, nonceA: Data) {
        sentChallenges.append((peerID, noiseKeyHex, nonceA))
@@ -277,6 +281,7 @@ struct ChatVerificationCoordinatorContextTests {
        #expect(context.encryptionStatuses[peerID] == .noiseVerified)
        #expect(context.stablePeerIDCache[peerID] == PeerID(hexData: noiseKey))
        #expect(context.invalidatedEncryptionCachePeers.contains(peerID))
+        #expect(context.privateMediaAuthenticatedPeers == [peerID])

        // Handshake required -> handshaking status.
        callbacks?.onHandshakeRequired(peerID)
@@ -364,6 +364,217 @@ struct PrivateMediaEndToEndTests {
        #expect(alice.privateMediaSendPolicy(to: bob.myPeerID) == .legacyRequiresConsent)
    }

+    @Test
+    func privateMediaRetryRequiresExactAuthenticatedBit9Proof() async throws {
+        let root = FileManager.default.temporaryDirectory
+            .appendingPathComponent(
+                "private-media-receipt-proof-\(UUID().uuidString)",
+                isDirectory: true
+            )
+        defer { try? FileManager.default.removeItem(at: root) }
+        let alice = makeService(
+            baseDirectory: root.appendingPathComponent(
+                "alice",
+                isDirectory: true
+            )
+        )
+        let bob = makeService(
+            baseDirectory: root.appendingPathComponent(
+                "bob",
+                isDirectory: true
+            )
+        )
+        let bothCapabilities: PeerCapabilities = [
+            .privateMedia,
+            .privateMediaReceipts
+        ]
+
+        // A public bit-9 announce is discovery only.
+        alice._test_seedConnectedPeer(
+            bob.myPeerID,
+            nickname: "Bob",
+            capabilities: bothCapabilities,
+            noisePublicKey: bob.noiseStaticPublicKeyData()
+        )
+        #expect(
+            alice.authenticatedPrivateMediaReceiptSessionGeneration(
+                to: bob.myPeerID
+            ) == nil
+        )
+
+        let proofs = try await establishSessionCapturingPeerState(
+            alice: alice,
+            bob: bob
+        )
+        #expect(
+            alice.authenticatedPrivateMediaReceiptSessionGeneration(
+                to: bob.myPeerID
+            ) == nil
+        )
+
+        // Bit 8 alone preserves encrypted transfer compatibility but cannot
+        // authorize automatic resend.
+        let privateMediaOnly = try authenticatedPeerStatePacket(
+            from: bob,
+            to: alice,
+            capabilities: .privateMedia
+        )
+        alice._test_handlePacket(
+            privateMediaOnly,
+            fromPeerID: bob.myPeerID
+        )
+        #expect(await TestHelpers.waitUntil(
+            {
+                alice.privateMediaSendPolicy(to: bob.myPeerID)
+                    == .encrypted
+            },
+            timeout: TestConstants.longTimeout
+        ))
+        #expect(
+            alice.authenticatedPrivateMediaReceiptSessionGeneration(
+                to: bob.myPeerID
+            ) == nil
+        )
+
+        let receiptCapable = try authenticatedPeerStatePacket(
+            from: bob,
+            to: alice,
+            capabilities: bothCapabilities
+        )
+        alice._test_handlePacket(
+            receiptCapable,
+            fromPeerID: bob.myPeerID
+        )
+        #expect(await TestHelpers.waitUntil(
+            {
+                alice.authenticatedPrivateMediaReceiptSessionGeneration(
+                    to: bob.myPeerID
+                ) != nil
+            },
+            timeout: TestConstants.longTimeout
+        ))
+
+        bob._test_handlePacket(
+            proofs.alice,
+            fromPeerID: alice.myPeerID
+        )
+        alice._test_onOutboundPacket = nil
+        bob._test_onOutboundPacket = nil
+    }
+
+    @Test
+    func receiptRetryRechecksBit9AtDeferredTransportBoundary() async throws {
+        let root = FileManager.default.temporaryDirectory
+            .appendingPathComponent(
+                "private-media-retry-proof-race-\(UUID().uuidString)",
+                isDirectory: true
+            )
+        defer { try? FileManager.default.removeItem(at: root) }
+        let alice = makeService(
+            baseDirectory: root.appendingPathComponent(
+                "alice",
+                isDirectory: true
+            )
+        )
+        let bob = makeService(
+            baseDirectory: root.appendingPathComponent(
+                "bob",
+                isDirectory: true
+            )
+        )
+        let receiptCapabilities: PeerCapabilities = [
+            .privateMedia,
+            .privateMediaReceipts
+        ]
+        alice._test_seedConnectedPeer(
+            bob.myPeerID,
+            nickname: "Bob",
+            capabilities: receiptCapabilities,
+            noisePublicKey: bob.noiseStaticPublicKeyData()
+        )
+        bob._test_seedConnectedPeer(
+            alice.myPeerID,
+            nickname: "Alice",
+            capabilities: receiptCapabilities,
+            noisePublicKey: alice.noiseStaticPublicKeyData()
+        )
+        try await establishSession(alice: alice, bob: bob)
+        #expect(
+            alice.authenticatedPrivateMediaReceiptSessionGeneration(
+                to: bob.myPeerID
+            ) != nil
+        )
+
+        let privateMediaOnly = try authenticatedPeerStatePacket(
+            from: bob,
+            to: alice,
+            capabilities: .privateMedia
+        )
+        let transferID =
+            "receipt-proof-race-\(UUID().uuidString)"
+        let tap = PacketTap()
+        let boundaryProofs = ReceiptCapabilityRecorder()
+        let rejections = TransferCancellationRecorder()
+        let cancellable = TransferProgressManager.shared.publisher.sink {
+            rejections.record($0)
+        }
+        alice._test_onOutboundPacket = tap.record
+        alice._test_beforePrivateMediaDeferredSend = { id in
+            guard id == transferID else { return }
+            boundaryProofs.record(
+                alice
+                    .authenticatedPrivateMediaReceiptSessionGeneration(
+                        to: bob.myPeerID
+                    ) != nil
+            )
+        }
+        defer {
+            alice._test_beforePrivateMediaDeferredSend = nil
+            alice._test_onOutboundPacket = nil
+        }
+
+        // Rotate authenticated state before the deferred retry reaches its
+        // admission boundary.
+        alice._test_handlePacket(
+            privateMediaOnly,
+            fromPeerID: bob.myPeerID
+        )
+        let content = Data("%PDF-1.7\nreceipt-proof-race".utf8)
+        alice.sendFilePrivateReceiptRetry(
+            BitchatFilePacket(
+                fileName: "receipt-proof-race.pdf",
+                fileSize: UInt64(content.count),
+                mimeType: "application/pdf",
+                content: content
+            ),
+            to: bob.myPeerID,
+            transferId: transferID
+        )
+        #expect(await TestHelpers.waitUntil(
+            { boundaryProofs.snapshot() == [false] },
+            timeout: TestConstants.longTimeout
+        ))
+        await alice._test_drainPrivateMediaSendPipeline()
+
+        #expect(await TestHelpers.waitUntil(
+            { rejections.contains(transferID) },
+            timeout: TestConstants.longTimeout
+        ))
+        #expect(tap.snapshot().allSatisfy {
+            $0.type != MessageType.fileTransfer.rawValue
+                && !(
+                    $0.type == MessageType.noiseEncrypted.rawValue
+                        && $0.version == 2
+                )
+        })
+        let state = alice._test_privateMediaTransferState(
+            transferId: transferID
+        )
+        #expect(!state.admissionActive)
+        #expect(!state.pendingNoise)
+        _ = cancellable
+    }
+
    @Test
    func capabilityAnnounceCannotPoisonPinWithoutMatchingNoiseAuthentication() async throws {
        let root = FileManager.default.temporaryDirectory
@@ -1397,6 +1608,23 @@ private final class PrivateMediaPolicyRecorder: @unchecked Sendable {
    }
 }

+private final class ReceiptCapabilityRecorder: @unchecked Sendable {
+    private let lock = NSLock()
+    private var values: [Bool] = []
+
+    func record(_ value: Bool) {
+        lock.lock()
+        values.append(value)
+        lock.unlock()
+    }
+
+    func snapshot() -> [Bool] {
+        lock.lock()
+        defer { lock.unlock() }
+        return values
+    }
+}
+
 private final class MessageCaptureDelegate: BitchatDelegate, @unchecked Sendable {
    private let lock = NSLock()
    private var messages: [BitchatMessage] = []