Fix cancellation, heartbeat, and LSP symbol budget issues

changelog.d/unreleased/3658.fixed.md

@@ -0,0 +1,19 @@
+---
+category: fixed
+issues:
+  - 3658
+affected:
+  - src/CodeIndex/Cli/SuggestionStore.cs
+  - src/CodeIndex/Lsp/LspServer.cs
+  - src/CodeIndex/Mcp/McpToolHandlers.cs
+  - tests/CodeIndex.Tests/McpServerTests.cs
+  - tests/CodeIndex.Tests/SuggestionStoreTests.cs
+---
+
+## English
+
+- Route caller cancellation through MCP status update checks, add a cancellable suggestion submission overload, and document compatibility no-token LSP/suggestion wrappers.
+
+## 日本語
+
+- MCP status update check に caller cancellation を渡し、キャンセル可能な suggestion submission overload を追加し、LSP / suggestion の no-token 互換 wrapper を明記しました。

changelog.d/unreleased/3705.fixed.md

@@ -0,0 +1,18 @@
+---
+category: fixed
+issues:
+  - 3705
+affected:
+  - src/CodeIndex/Cli/IndexCommandRunner.FullScan.cs
+  - src/CodeIndex/Cli/IndexCommandRunner.UpdateTargets.cs
+  - src/CodeIndex/Mcp/HttpMcpTransport.cs
+  - tests/CodeIndex.Tests/IndexCommandRunnerHeartbeatTests.cs
+---
+
+## English
+
+- Route JSON index heartbeat tasks and HTTP MCP request-handler tasks through observed background work while keeping expected cancellation quiet and preserving handler-slot cleanup during shutdown.
+
+## 日本語
+
+- JSON index heartbeat タスクと HTTP MCP request-handler タスクを監視対象の background work に通し、期待されるキャンセルでは診断を出さず、shutdown 中も handler slot cleanup を保つようにしました。

changelog.d/unreleased/3743.fixed.md

@@ -0,0 +1,16 @@
+---
+category: fixed
+issues:
+  - 3743
+affected:
+  - src/CodeIndex/Lsp/LspServer.cs
+  - tests/CodeIndex.Tests/LspServerTests.cs
+---
+
+## English
+
+- Avoid repeated full JSON serialization passes while trimming oversized LSP document-symbol responses.
+
+## 日本語
+
+- サイズ超過した LSP document-symbol response を trim する際、root 全体の JSON serialization を繰り返さないようにしました。

changelog.d/unreleased/3758.fixed.md

@@ -0,0 +1,16 @@
+---
+category: fixed
+issues:
+  - 3758
+affected:
+  - src/CodeIndex/Lsp/LspServer.cs
+  - tests/CodeIndex.Tests/LspServerTests.cs
+---
+
+## English
+
+- Cap LSP document-symbol materialization before sorting and emit diagnostics when candidate materialization is truncated.
+
+## 日本語
+
+- LSP document-symbol の候補 materialization を sort 前に制限し、候補が truncation された場合は diagnostics を出すようにしました。

changelog.d/unreleased/3760.fixed.md

@@ -0,0 +1,16 @@
+---
+category: fixed
+issues:
+  - 3760
+affected:
+  - src/CodeIndex/Diagnostics/BackgroundTaskObserver.cs
+  - tests/CodeIndex.Tests/BackgroundTaskObserverTests.cs
+---
+
+## English
+
+- Honor shutdown cancellation when scheduling observed background work.
+
+## 日本語
+
+- 監視対象のバックグラウンド処理をスケジュールする際に shutdown cancellation を反映するようにしました。

src/CodeIndex/Cli/IndexCommandRunner.FullScan.cs

@@ -672,33 +672,12 @@ private static (CancellationTokenSource Cts, Task Task)? StartFullScanJsonPhaseH
         string phase,
         Func<string?>? detailProvider = null)
     {
-        if (!options.Json || options.Quiet)
-            return null;
-
-        var cts = new CancellationTokenSource();
-        var token = cts.Token;
-        var task = Task.Run(async () =>
-        {
-            while (!token.IsCancellationRequested)
-            {
-                try
-                {
-                    await Task.Delay(TimeSpan.FromSeconds(5), token).ConfigureAwait(false);
-                }
-                catch (OperationCanceledException)
-                {
-                    break;
-                }
-
-                if (token.IsCancellationRequested)
-                    break;
-
-                var detail = detailProvider?.Invoke();
-                var suffix = string.IsNullOrWhiteSpace(detail) ? string.Empty : $": {detail}";
-                ConsoleUi.TryWriteErrorLine($"cdidx: still {phase}{suffix}...");
-            }
-        }, token);
-        return (cts, task);
+        return StartObservedJsonPhaseHeartbeat(
+            options.Json && !options.Quiet,
+            "cdidx-index",
+            phase,
+            ConsoleUi.TryWriteErrorLine,
+            detailProvider);
     }
 
     private static void StopFullScanJsonPhaseHeartbeat((CancellationTokenSource Cts, Task Task)? heartbeat)

src/CodeIndex/Cli/IndexCommandRunner.UpdateTargets.cs

@@ -1,4 +1,5 @@
 using System.Text.Json;
+using CodeIndex.Diagnostics;
 
 namespace CodeIndex.Cli;
 
@@ -122,33 +123,64 @@ private static (CancellationTokenSource Cts, Task Task)? StartIndexJsonPhaseHear
         string phase,
         Func<string?>? detailProvider = null)
     {
-        if (!options.Json || options.Quiet)
+        return StartObservedJsonPhaseHeartbeat(
+            options.Json && !options.Quiet,
+            "cdidx-index",
+            phase,
+            ConsoleUi.TryWriteErrorLine,
+            detailProvider);
+    }
+
+    internal static (CancellationTokenSource Cts, Task Task)? StartObservedJsonPhaseHeartbeat(
+        bool enabled,
+        string component,
+        string phase,
+        Action<string> messageWriter,
+        Func<string?>? detailProvider = null,
+        TimeSpan? interval = null,
+        Action<string>? warningWriter = null)
+    {
+        if (!enabled)
             return null;
 
+        ArgumentNullException.ThrowIfNull(messageWriter);
+
         var cts = new CancellationTokenSource();
-        var token = cts.Token;
-        var task = Task.Run(async () =>
+        var heartbeatInterval = interval ?? TimeSpan.FromSeconds(5);
+        var task = BackgroundTaskObserver.Run(
+            token => RunObservedJsonPhaseHeartbeatLoop(phase, messageWriter, detailProvider, heartbeatInterval, token),
+            component,
+            $"{phase} heartbeat",
+            cts.Token,
+            warningWriter);
+        return (cts, task);
+    }
+
+    private static async Task RunObservedJsonPhaseHeartbeatLoop(
+        string phase,
+        Action<string> messageWriter,
+        Func<string?>? detailProvider,
+        TimeSpan interval,
+        CancellationToken token)
+    {
+        while (!token.IsCancellationRequested)
         {
-            while (!token.IsCancellationRequested)
+            try
             {
-                try
-                {
-                    await Task.Delay(TimeSpan.FromSeconds(5), token).ConfigureAwait(false);
-                }
-                catch (OperationCanceledException)
-                {
-                    break;
-                }
+                await Task.Delay(interval, token).ConfigureAwait(false);
+            }
+            catch (OperationCanceledException) when (token.IsCancellationRequested)
+            {
+                break;
+            }
 
-                if (token.IsCancellationRequested)
-                    break;
+            if (token.IsCancellationRequested)
+                break;
 
-                var detail = detailProvider?.Invoke();
-                var suffix = string.IsNullOrWhiteSpace(detail) ? string.Empty : $": {detail}";
-                CommandErrorWriter.WriteStderr($"cdidx: still {phase}{suffix}...");
-            }
-        }, token);
-        return (cts, task);
+            var detail = detailProvider?.Invoke();
+            var suffix = string.IsNullOrWhiteSpace(detail) ? string.Empty : $": {detail}";
+            messageWriter($"cdidx: still {phase}{suffix}...");
+        }
     }
 
     private static void StopIndexJsonPhaseHeartbeat((CancellationTokenSource Cts, Task Task)? heartbeat)

src/CodeIndex/Cli/SuggestionStore.cs

@@ -206,9 +206,14 @@ public record SubmitAttemptResult(string? IssueUrl, string? Error, DateTime? Nex
     /// Add a suggestion under the file lock, then attempt GitHub submission outside the lock.
     /// The store reserves the attempt before releasing the lock so concurrent callers do not
     /// also submit the same unsubmitted duplicate while the remote API is slow.
+    /// This compatibility wrapper has no caller cancellation; use the overload that accepts
+    /// <see cref="CancellationToken"/> when cancellation should be observed.
     /// 提案をファイルロック内で追加し、その後 GitHub 送信はロック外で試行する。
     /// remote API が遅い間に並行呼び出しが同じ未送信重複を送信しないよう、
     /// ロック解放前に送信試行を予約する。
+    /// この互換 wrapper は caller cancellation を持たない。キャンセルを監視する場合は
+    /// <see cref="TryAddAndSubmit(SuggestionRecord, Func{SuggestionRecord, SubmitAttemptResult}?, CancellationToken)"/>
+    /// を使う。
     /// </summary>
     /// <param name="record">The suggestion to add / 追加する提案</param>
     /// <param name="submitToGitHub">
@@ -218,13 +223,19 @@ public record SubmitAttemptResult(string? IssueUrl, string? Error, DateTime? Nex
     /// 未送信の重複）にのみロック外で呼ばれる。成功時は Issue URL を返す。
     /// </param>
     public AddAndSubmitResult TryAddAndSubmit(SuggestionRecord record, Func<SuggestionRecord, SubmitAttemptResult>? submitToGitHub)
+        => TryAddAndSubmit(record, submitToGitHub, CancellationToken.None);
+
+    public AddAndSubmitResult TryAddAndSubmit(
+        SuggestionRecord record,
+        Func<SuggestionRecord, SubmitAttemptResult>? submitToGitHub,
+        CancellationToken cancellationToken)
     {
         return TryAddAndSubmitAsync(
             record,
             submitToGitHub == null
                 ? null
                 : (r, _) => Task.FromResult(submitToGitHub(r)),
-            CancellationToken.None).GetAwaiter().GetResult();
+            cancellationToken).GetAwaiter().GetResult();
     }
 
     public async Task<AddAndSubmitResult> TryAddAndSubmitAsync(

src/CodeIndex/Diagnostics/BackgroundTaskObserver.cs

@@ -15,7 +15,7 @@ internal static Task Run(
     {
         ArgumentNullException.ThrowIfNull(action);
 
-        return Observe(Task.Run(action, CancellationToken.None), component, operation, warningWriter);
+        return Run(_ => action(), component, operation, CancellationToken.None, warningWriter);
     }
 
     internal static Task Run(
@@ -27,7 +27,7 @@ internal static Task Run(
     {
         ArgumentNullException.ThrowIfNull(action);
 
-        return Observe(Task.Run(() => action(cancellationToken), CancellationToken.None), component, operation, warningWriter);
+        return Observe(Task.Run(() => action(cancellationToken), cancellationToken), component, operation, warningWriter);
     }
 
     internal static Task Observe(