Improve error handling

RiotSwiftUI/Modules/Room/PollHistory/Service/MatrixSDK/PollHistoryService.swift

@@ -22,7 +22,7 @@ final class PollHistoryService: PollHistoryServiceProtocol {
     private let room: MXRoom
     private let chunkSizeInDays: UInt
     private let pollsSubject: PassthroughSubject<TimelinePollDetails, Never> = .init()
-    private let errorSubject: PassthroughSubject<Error, Never> = .init()
+    private let errorSubject: PassthroughSubject<PollHistoryError, Never> = .init()
     private let isFetchingSubject: PassthroughSubject<Bool, Never> = .init()
     
     private var listner: Any?
@@ -35,7 +35,7 @@ final class PollHistoryService: PollHistoryServiceProtocol {
         pollsSubject.eraseToAnyPublisher()
     }
     
-    var error: AnyPublisher<Error, Never> {
+    var error: AnyPublisher<PollHistoryError, Never> {
         errorSubject.eraseToAnyPublisher()
     }
     
@@ -60,7 +60,7 @@ final class PollHistoryService: PollHistoryServiceProtocol {
                 let self = self,
                 let timeline = timeline
             else {
-                #warning("Handle error")
+                self?.errorSubject.send(.timelineUnavailable)
                 return
             }
             
@@ -122,7 +122,7 @@ private extension PollHistoryService {
                     self.isFetchingSubject.send(false)
                 }
             case .failure(let error):
-                #warning("Handle error")
+                self.errorSubject.send(.paginationFailed(error))
                 self.isFetchingSubject.send(false)
             }
         }
@@ -155,7 +155,7 @@ extension PollHistoryService: PollAggregatorDelegate {
     }
     
     func pollAggregator(_ aggregator: PollAggregator, didFailWithError: Error) {
-        #warning("Handle error")
+        errorSubject.send(.pollAggregationFailed(didFailWithError))
     }
     
     func pollAggregatorDidUpdateData(_ aggregator: PollAggregator) {

RiotSwiftUI/Modules/Room/PollHistory/Service/Mock/MockPollHistoryService.swift

@@ -23,7 +23,7 @@ final class MockPollHistoryService: PollHistoryServiceProtocol {
         polls.eraseToAnyPublisher()
     }
     
-    var error: AnyPublisher<Error, Never> {
+    var error: AnyPublisher<PollHistoryError, Never> {
         Empty().eraseToAnyPublisher()
     }
 

RiotSwiftUI/Modules/Room/PollHistory/Service/PollHistoryServiceProtocol.swift

@@ -22,12 +22,18 @@ protocol PollHistoryServiceProtocol {
     var pollHistory: AnyPublisher<TimelinePollDetails, Never> { get }
     
     /// Publishes whatever errors produced during the sync.
-    var error: AnyPublisher<Error, Never> { get }
+    var error: AnyPublisher<PollHistoryError, Never> { get }
     
     /// Ask to fetch the next batch of polls.
     /// Concrete implementations can decide what a batch is.
     func next()
     
-    /// Inform the whenever a new batch of polls starts or ends.
+    /// Inform whenever the fetch of a new batch of polls starts or ends.
     var isFetching: AnyPublisher<Bool, Never> { get }
 }
+
+enum PollHistoryError: Error {
+    case paginationFailed(Error)
+    case timelineUnavailable
+    case pollAggregationFailed(Error)
+}