fix-issue-159:修复 Mac 端 PR 与 Git 窗口切换卡顿问题

Sources/Lithe/Application/Features/GitHubFeatureModel.swift

@@ -8,6 +8,12 @@ final class GitHubFeatureModel: ObservableObject {
         static let branchCacheLifetime: TimeInterval = 60
     }
 
+    private struct PullRequestDetails {
+        let request: GitHubPullRequest
+        let files: [GitHubPullRequestFile]
+        let comments: [GitHubComment]
+    }
+
     enum ConnectionState: Equatable {
         case disconnected
         case restoring
@@ -56,6 +62,8 @@ final class GitHubFeatureModel: ObservableObject {
     private var authorizationTask: Task<Void, Never>?
     private var branchLoadTask: (id: UUID, task: Task<[GitHubBranch], Error>)?
     private var branchesLoadedAt: Date?
+    private var refreshGeneration = UUID()
+    private var pullRequestSelectionGeneration = UUID()
 
     init(
         service: GitHubService,
@@ -123,6 +131,8 @@ final class GitHubFeatureModel: ObservableObject {
 
     func disconnect() async {
         authorizationTask?.cancel()
+        refreshGeneration = UUID()
+        pullRequestSelectionGeneration = UUID()
         do {
             try await service.disconnect()
             connectionState = .disconnected
@@ -147,14 +157,20 @@ final class GitHubFeatureModel: ObservableObject {
 
     func refresh(workspaceURL: URL?) async {
         guard case .connected = connectionState else { return }
+        let generation = UUID()
+        refreshGeneration = generation
+        pullRequestSelectionGeneration = UUID()
         contentState = .loading
         do {
             let repository = try await service.resolveRepository(at: workspaceURL)
+            guard !Task.isCancelled, refreshGeneration == generation else { return }
             let branchDefaults = try await service.resolvePullRequestBranchDefaults(at: workspaceURL)
+            guard !Task.isCancelled, refreshGeneration == generation else { return }
             let pullRequests = try await service.listPullRequests(
                 repository: repository,
                 state: listState
             )
+            guard !Task.isCancelled, refreshGeneration == generation else { return }
             if self.repository != repository {
                 branches = []
                 branchContentState = .idle
@@ -166,13 +182,15 @@ final class GitHubFeatureModel: ObservableObject {
             if let selectedNumber = selectedPullRequest?.number,
                pullRequests.contains(where: { $0.number == selectedNumber }) {
                 await selectPullRequest(number: selectedNumber)
+                return
             } else {
                 selectedPullRequest = nil
                 files = []
                 comments = []
             }
             contentState = .ready
         } catch {
+            guard !Task.isCancelled, refreshGeneration == generation else { return }
             contentState = .failed(error.localizedDescription)
         }
     }
@@ -284,21 +302,41 @@ final class GitHubFeatureModel: ObservableObject {
 
     func selectPullRequest(number: UInt64) async {
         guard let repository else { return }
+        let generation = UUID()
+        pullRequestSelectionGeneration = generation
         isCreatingPullRequest = false
         contentState = .loading
         do {
-            async let request = service.pullRequest(repository: repository, number: number)
-            async let files = service.files(repository: repository, number: number)
-            async let comments = service.comments(repository: repository, number: number)
-            selectedPullRequest = try await request
-            self.files = try await files
-            self.comments = try await comments
+            let details = try await pullRequestDetails(repository: repository, number: number)
+            guard !Task.isCancelled,
+                  pullRequestSelectionGeneration == generation,
+                  self.repository == repository else { return }
+            selectedPullRequest = details.request
+            files = details.files
+            comments = details.comments
             contentState = .ready
         } catch {
+            guard !Task.isCancelled,
+                  pullRequestSelectionGeneration == generation,
+                  self.repository == repository else { return }
             contentState = .failed(error.localizedDescription)
         }
     }
 
+    private func pullRequestDetails(
+        repository: GitHubRepository,
+        number: UInt64
+    ) async throws -> PullRequestDetails {
+        async let request = service.pullRequest(repository: repository, number: number)
+        async let files = service.files(repository: repository, number: number)
+        async let comments = service.comments(repository: repository, number: number)
+        return try await PullRequestDetails(
+            request: request,
+            files: files,
+            comments: comments
+        )
+    }
+
     func createPullRequest(
         title: String,
         body: String,

Sources/Lithe/Models/AppModel/AppModel.swift

@@ -43,13 +43,21 @@ final class AppModel: ObservableObject, Identifiable {
     @Published private(set) var standaloneFileURL: URL?
     @Published var selectedSidebar: SidebarDestination = .project {
         didSet {
-            if selectedSidebar == .changes, oldValue != .changes {
-                Task { [weak self] in await self?.refreshGit() }
-            }
-            if selectedSidebar == .pullRequests, oldValue != .pullRequests {
-                Task { [weak self] in
-                    guard let self else { return }
+            guard oldValue != selectedSidebar else { return }
+            sidebarRefreshTask?.cancel()
+            sidebarRefreshTask = nil
+            // Sidebar changes can happen faster than Git or GitHub can respond.
+            // Keep only the refresh associated with the currently visible pane.
+            sidebarRefreshTask = Task { @MainActor [weak self] in
+                guard let self else { return }
+                guard !Task.isCancelled else { return }
+                switch self.selectedSidebar {
+                case .changes:
+                    await self.refreshGit()
+                case .pullRequests:
                     await self.githubFeature.refresh(workspaceURL: self.workspaceURL)
+                default:
+                    break
                 }
             }
         }
@@ -136,6 +144,7 @@ final class AppModel: ObservableObject, Identifiable {
     @Published var blameVisibleURL: URL?
     @Published var gitLogSearchQuery = ""
     private var shortcutDetector: (any ShortcutDetector)?
+    private var sidebarRefreshTask: Task<Void, Never>?
     private var shortcutSettingsObservation: AnyCancellable?
     private var shortcutRecordingObservation: AnyCancellable?
     private var isProjectSessionActive = true
@@ -670,6 +679,7 @@ final class AppModel: ObservableObject, Identifiable {
 
     deinit {
         shortcutDetector?.stop()
+        sidebarRefreshTask?.cancel()
     }
 
     func configureProjectSession(

Sources/LitheGitModule/Application/GitFeatureModel.swift

@@ -79,7 +79,10 @@ package final class GitFeatureModel: ObservableObject {
     private var acquireModuleLease: (@MainActor (String) -> ModuleLease)?
     private var gitHistoryLimit = 300
     private var deferredSavedChanges: GitDeferredSavedChanges?
-    private var refreshRequestedWhileRunning = false
+    private var nextRefreshRequestID: UInt64 = 0
+    private var activeRefreshRequestIDs: Set<UInt64> = []
+    private var completedRefreshRequestID: UInt64 = 0
+    private var refreshCompletionWaiters: [UUID: CheckedContinuation<Void, Never>] = [:]
     private var loadingLineChangeURLs: Set<URL> = []
     private var lineChangeHunks: [URL: [String: DiffHunk]] = [:]
 
@@ -169,7 +172,6 @@ package final class GitFeatureModel: ObservableObject {
         gitDiffWhitespaceMode = .doNotIgnore
         isLoadingDiff = false
         isRefreshingGit = false
-        refreshRequestedWhileRunning = false
         pendingDiscardChange = nil
         pendingDiscardHunk = nil
         isCommitting = false
@@ -204,26 +206,79 @@ package final class GitFeatureModel: ObservableObject {
 
     package func refreshGit() async {
         guard let workspaceURLProvider else { return }
+        guard !Task.isCancelled else { return }
+        nextRefreshRequestID &+= 1
+        let requestID = nextRefreshRequestID
+        activeRefreshRequestIDs.insert(requestID)
+        defer { activeRefreshRequestIDs.remove(requestID) }
+        await fulfillGitRefreshRequest(requestID, workspaceURLProvider: workspaceURLProvider)
+    }
+
+    private func fulfillGitRefreshRequest(
+        _ requestID: UInt64,
+        workspaceURLProvider: @MainActor () -> URL?
+    ) async {
         if isRefreshingGit {
-            refreshRequestedWhileRunning = true
+            await waitForCurrentGitRefresh()
+            guard !Task.isCancelled else { return }
+            if completedRefreshRequestID < requestID {
+                await fulfillGitRefreshRequest(requestID, workspaceURLProvider: workspaceURLProvider)
+            }
             return
         }
         guard let workspaceURL = workspaceURLProvider() else {
             reset()
+            completedRefreshRequestID = max(completedRefreshRequestID, requestID)
             return
         }
 
         isRefreshingGit = true
+        defer { finishCurrentGitRefresh() }
         repeat {
-            refreshRequestedWhileRunning = false
+            guard !Task.isCancelled else { return }
+            let processingRequestID = activeRefreshRequestIDs.max() ?? requestID
             await refreshGitState(at: workspaceURL)
-        } while refreshRequestedWhileRunning && workspaceURLProvider() == workspaceURL
+            guard !Task.isCancelled else { return }
+            completedRefreshRequestID = max(completedRefreshRequestID, processingRequestID)
+        } while activeRefreshRequestIDs.contains(where: { $0 > completedRefreshRequestID })
+            && workspaceURLProvider() == workspaceURL
+    }
+
+    private func waitForCurrentGitRefresh() async {
+        let waiterID = UUID()
+        await withTaskCancellationHandler {
+            await withCheckedContinuation { continuation in
+                guard isRefreshingGit, !Task.isCancelled else {
+                    continuation.resume()
+                    return
+                }
+                refreshCompletionWaiters[waiterID] = continuation
+            }
+        } onCancel: {
+            Task { @MainActor [weak self] in
+                self?.resumeGitRefreshWaiter(waiterID)
+            }
+        }
+    }
+
+    private func finishCurrentGitRefresh() {
         isRefreshingGit = false
+        let waiters = Array(refreshCompletionWaiters.values)
+        refreshCompletionWaiters.removeAll()
+        for waiter in waiters {
+            waiter.resume()
+        }
+    }
+
+    private func resumeGitRefreshWaiter(_ waiterID: UUID) {
+        refreshCompletionWaiters.removeValue(forKey: waiterID)?.resume()
     }
 
     private func refreshGitState(at workspaceURL: URL) async {
+        guard !Task.isCancelled else { return }
         var didChange = false
         if let snapshot = await snapshotProvider(workspaceURL) {
+            guard !Task.isCancelled else { return }
             let changesChanged = gitChanges != snapshot.changes
             if gitRepositoryRoot != snapshot.repositoryRoot {
                 gitRepositoryRoot = snapshot.repositoryRoot
@@ -246,16 +301,19 @@ package final class GitFeatureModel: ObservableObject {
                 didChange = didChange || previousFilter != gitConflictFilterPaths
             }
             let stashes = await stashesProvider(snapshot.repositoryRoot)
+            guard !Task.isCancelled else { return }
             if gitStashes != stashes {
                 gitStashes = stashes
                 didChange = true
             }
             let shelves = await shelveService?.entries(for: snapshot.repositoryRoot) ?? []
+            guard !Task.isCancelled else { return }
             if gitShelves != shelves {
                 gitShelves = shelves
                 didChange = true
             }
             let operationState = await operationStateProvider(snapshot.repositoryRoot)
+            guard !Task.isCancelled else { return }
             if gitOperationState != operationState {
                 gitOperationState = operationState
                 didChange = true
@@ -275,6 +333,7 @@ package final class GitFeatureModel: ObservableObject {
                     didChange = true
                 }
                 let document = await diffDocumentProvider(updated, gitDiffWhitespaceMode)
+                guard !Task.isCancelled else { return }
                 if selectedDiffPatch != document.patch {
                     selectedDiffPatch = document.patch
                     diffRows = document.rows
@@ -304,9 +363,11 @@ package final class GitFeatureModel: ObservableObject {
         }
 
         if didChange && isGitLogVisibleProvider?() == true {
+            guard !Task.isCancelled else { return }
             await refreshGitHistory()
         }
         if didChange {
+            guard !Task.isCancelled else { return }
             await onStateRefreshed?()
         }
     }