Reject malformed LSP request envelopes and symbol query types

DEVELOPER_GUIDE.md

@@ -910,6 +910,14 @@ across live-text eviction and are cleared by `didClose`, so an evicted newer
 version cannot be replaced by a stale change. Other providers return empty
 arrays or null when the database cannot answer safely instead of inventing
 language-server analysis.
+Every inbound message must first be an object whose `jsonrpc` member is exactly
+the string `"2.0"`. Missing, null, non-string, or other-version envelope values
+return `-32600` (`Invalid Request`) with a valid request ID preserved; validation
+runs before receive-time lifecycle reservation, cancellation fast paths, method
+dispatch, state mutation, or database access. `workspace/symbol` separately
+requires `params.query` to be a JSON string. Missing, null, or non-string query
+values return `-32602` (`Invalid params`) before query-snapshot refresh or symbol
+search, while the valid empty string remains a supported workspace-wide query.
 Before URI/path resolution, live-document access, or query-snapshot refresh,
 one shared coordinate validator checks every supported position/range-bearing
 method. `definition`, `declaration`, `references`, `hover`, `completion`, and
@@ -5127,6 +5135,14 @@ indexed symbol に fallback する。numeric document-version tombstone は live
 後も上限付きで保持し、`didClose` で消去するため、evict 済みの新しい version を stale change が
 置き換えることはない。それ以外の provider は database が安全に答えられない場合、
 language-server analysis を作り上げず、空配列または null を返す。
+すべての inbound message は、まず object であり、その `jsonrpc` member が文字列 `"2.0"` と
+完全一致しなければならない。欠落、null、文字列以外、または別 version の envelope 値には、
+有効な request ID を維持して `-32600`（`Invalid Request`）を返す。この検証は receive-time の
+lifecycle reservation、cancellation fast path、method dispatch、state mutation、database access
+より前に行う。`workspace/symbol` では、これとは別に `params.query` を JSON string として必須に
+する。query が欠落、null、または文字列以外なら query snapshot の refresh や symbol search より
+前に `-32602`（`Invalid params`）を返す一方、正当な空文字列は workspace-wide query として
+引き続き対応する。
 URI / path 解決、live document へのアクセス、query snapshot の refresh より前に、1つの共通
 coordinate validator ですべての対応済み position / range method を検証する。
 `definition`、`declaration`、`references`、`hover`、`completion`、

TESTING_GUIDE.md

@@ -692,6 +692,7 @@ Candidate-ordered parallel-index recovery tests must prove that the fatal result
 - `LspServerTests.cs`
   LSP JSON-RPC behavior and indexed editor semantics. Reference parity coverage must compare LSP locations with the matching CLI candidate bundle, including overload identity and both `includeDeclaration` states. Keep document/workspace identifier ranges and explicit-versus-inferred inlay hints in one source-semantics fixture so persisted-column anchoring, source confirmation, and hint suppression cannot drift independently.
   Lifecycle transport coverage must stage initialization before sending shutdown/exit, use a caller-owned stream whose read after the exit frame cannot be interrupted by cancellation, and assert the shutdown response, success versus exit-before-shutdown status, and absence of any post-exit read. Keep finite EOF, malformed-frame, and caller-cancellation coverage alongside it so early transport completion cannot weaken those paths.
+  Issue-5231 request-boundary coverage uses framed transcripts to prove that an invalid-version initialize cannot mutate lifecycle state before a valid initialize, then sends every missing/null/non-string/wrong-version `jsonrpc` and missing/null/non-string `workspace/symbol.query` case after initialization. Keep valid empty and non-empty query controls in the same seeded fixture, preserve typed response IDs and stable error codes, and assert that rejected frames never reach receive-time reservation, method dispatch, symbol search, or `lsp.request` activity. Separately stage an invalid-version cancellation while a symbol request is active, prove it remains active until a valid cancellation arrives, and pin malformed-envelope/invalid-query error precedence over the overload response.
   The issue-4870 kind-mapping matrix seeds every registered built-in internal kind plus semantic constructor and enum-member rows, then asserts decoded document-symbol, workspace-symbol, and completion responses. It also feeds real TypeScript, Kotlin, Solidity, Java, Swift, Dart, Visual Basic, Pascal, C#, and Shell extractor output through the shared mapper so keyword, compact, named, dedicated-name, and verbatim-identifier constructors; same-name, return-typed, object/static, and shell non-constructors; decorated, escaped, indirect, and comma-grouped enum entries; and nested enums cannot invert classification. It separately pins the conservative parameter and unknown/plugin fallback. Keep all three protocol surfaces in that one fixture so constructor/import handling and deliberate fallback mappings cannot drift.
   Coordinate-validation coverage keeps every supported position provider in one negative/malformed/overflow matrix, with missing-document precedence and missing/reversed inlay ranges in the same read-only fixture. Keep UTF-16 and EOF success controls together, but retain invalid ranged-`didChange` as a separate mutable-state fixture so a rejected notification cannot replace accepted live text (#4869).
   C# semantic-token coverage decodes LSP delta coordinates and pairs the same keyword/modifier, namespace/type, method/property/event/enum-member, parameter/variable/field, generic/record-struct, explicit-interface-member, attribute, using-declaration, accessor-local, numeric member-access, escaped/contextual-identifier, interpolation, comma-separated declaration, and declaration-kind fixture with `QueryCommandRunnerTests.RunExcerpt_JsonCSharpSemanticKindsMatchLspClassifier_Issue4852`. Keep both surfaces on the shared source classifier, retain ordering/non-overlap assertions, preserve the narrow excerpt check whose parameter/type-parameter declarations are outside the returned range, and retain `RunExcerpt_JsonCSharpSemanticTokensUseVisibleRangeBudget_Issue4852` so earlier tokens cannot empty a late excerpt while indexed-source reconstruction remains line/character bounded. `HandleMessage_SemanticTokens_FallsBackToIndexedCSharpSymbolsWhenSourceReadFails_Issue4852` keeps indexed declaration tokens available when bounded source loading fails.
@@ -1849,6 +1850,7 @@ dotnet test --filter "FullyQualifiedName~GitHelperTests"
 - `LspServerTests.cs`
   LSP の JSON-RPC 挙動と indexed editor semantics のテスト。reference parity coverage では、overload identity と `includeDeclaration` の両状態を含め、LSP location と対応する CLI candidate bundle を比較してください。document/workspace の identifier range と explicit/inferred inlay hint は 1 つの source-semantics fixture にまとめ、保存済み column の anchoring、source 上の確認、hint 抑制が別々に drift しないようにします。
   lifecycle transport coverage では、shutdown/exit の送信前に initialization を stage し、exit frame 後の read が cancellation では中断されない caller-owned stream を使い、shutdown response、success と shutdown 前 exit の status の違い、post-exit read が一度も始まらないことを検証してください。早期 transport completion によって他経路が弱まらないよう、finite EOF、malformed frame、caller cancellation の coverage も並行して維持します。
+  issue-5231 の request boundary coverage は framed transcript を使い、不正 version の initialize が lifecycle state を変更せず、その後の正当な initialize が成功することを検証します。続いて initialization 後に、`jsonrpc` の欠落・null・文字列以外・別 version と、`workspace/symbol.query` の欠落・null・文字列以外をすべて送ります。同じ seed 済み fixture に空文字列と非空文字列の正当な query control を保ち、型付き response ID と安定した error code を維持し、拒否 frame が receive-time reservation、method dispatch、symbol search、`lsp.request` activity のいずれにも到達しないことを確認してください。別途、symbol request の実行中に不正 version の cancellation を stage し、正当な cancellation が届くまで request が active のままであること、および malformed envelope / invalid query の error が overload response より優先されることを固定してください。
   issue-4870 の kind-mapping matrix は、登録済みの全 built-in internal kind に加えて semantic な constructor と enum-member の row を seed し、decode 済みの document-symbol、workspace-symbol、completion response を検証します。また、実際の TypeScript、Kotlin、Solidity、Java、Swift、Dart、Visual Basic、Pascal、C#、Shell extractor 出力を shared mapper に通し、keyword / compact / named / 専用名 / 逐語識別子 constructor、同名 / 戻り値型付き / object・static / shell の非 constructor、annotation 付き / escape 済み / indirect / comma-grouped enum entry、nested enum の分類が逆転しないようにします。保守的な parameter および未知/plugin fallback は別途固定します。constructor/import の処理と意図的な fallback mapping がずれないよう、3つの protocol surface を同じ fixture に維持してください。
   coordinate validation coverage は、対応済みの全 position provider を1つの負数 / malformed / overflow matrix にまとめ、missing document より検証を優先することと、inlay range の欠落 / 逆順も同じ read-only fixture で検証します。UTF-16 と EOF の成功 control は一緒に維持し、不正な range 付き `didChange` は mutable state の独立 fixture として残して、拒否された notification が受理済み live text を置き換えられないことを検証してください（#4869）。
   C# semantic-token coverage は LSP の delta 座標を decode し、同じ keyword/modifier、namespace/type、method/property/event/enum-member、parameter/variable/field、generic/record struct、explicit interface member、attribute、using declaration、accessor local、numeric member access、escaped/contextual identifier、interpolation、comma-separated declaration、declaration kind の fixture を `QueryCommandRunnerTests.RunExcerpt_JsonCSharpSemanticKindsMatchLspClassifier_Issue4852` と対にします。両 surface が shared source classifier を使い続け、順序と非 overlap の assertion、parameter / type-parameter の declaration が返却範囲外にある narrow excerpt の検証、および indexed-source reconstruction を line / character 上限内に保ちながら手前の token によって file 後半の excerpt が空にならないことを保証する `RunExcerpt_JsonCSharpSemanticTokensUseVisibleRangeBudget_Issue4852` を維持してください。`HandleMessage_SemanticTokens_FallsBackToIndexedCSharpSymbolsWhenSourceReadFails_Issue4852` は bounded source loading が失敗しても indexed declaration token を利用できる状態を維持します。

USER_GUIDE.md

@@ -3297,10 +3297,16 @@ message bodies, so Ctrl-C / host cancellation can interrupt pending frame reads
 instead of waiting for another complete request.
 Unknown-method diagnostics echo at most 240 method-name characters with `...`
 when the method name is longer. Request IDs must be bounded JSON-RPC scalar
-values: strings are capped at 256
+values. Every inbound LSP message must be an object whose `jsonrpc` member is
+exactly the string `"2.0"`; missing, null, non-string, or other-version values
+return `-32600` (`Invalid Request`) before lifecycle reservation, cancellation,
+dispatch, state mutation, or database access, while preserving a valid request
+ID. Request-ID strings are capped at 256
 characters, integer IDs must fit in `Int64`, and non-scalar IDs are rejected as
-invalid requests before response IDs are cloned. `workspace/symbol` query
-strings are capped at 1000 characters before symbol search runs.
+invalid requests before response IDs are cloned. `workspace/symbol.params.query`
+is a required JSON string; missing, null, or non-string values return `-32602`
+(`Invalid params`) before symbol search, while the empty string remains valid.
+Query strings are capped at 1000 characters before symbol search runs.
 `workspace/symbol` accepts optional numeric `limit` / `maxResults` parameters
 and clamps them to 1000 results. `textDocument/documentSymbol` returns
 hierarchical `DocumentSymbol` children when container metadata is available,
@@ -6929,10 +6935,16 @@ stdio loop は header / message body 読み取り中も CLI cancellation token 
 Ctrl-C や host cancellation が次の完全な request を待たずに pending frame read を中断できます。
 method-not-found diagnostic で echo する method name は最大 240 文字に制限され、
 長い場合は `...` を付けて切り詰めます。
+すべての受信 LSP message は object であり、`jsonrpc` member が文字列 `"2.0"` と完全一致する
+必要があります。欠落、null、文字列以外、または別 version の値には、有効な request ID を
+維持して `-32600`（`Invalid Request`）を返します。この検証は lifecycle reservation、
+cancellation、dispatch、state mutation、database access より前に行います。
 request ID は bounded な JSON-RPC scalar value に限定され、string は 256 文字まで、
 integer ID は `Int64` に収まるものだけを受理し、non-scalar ID は response ID を複製する前に
 invalid request として拒否します。
-`workspace/symbol` の query string は symbol search を実行する前に 1000 文字で上限をかけます。
+`workspace/symbol.params.query` は必須の JSON string です。欠落、null、文字列以外の値には
+symbol search より前に `-32602`（`Invalid params`）を返す一方、空文字列は引き続き有効です。
+query string は symbol search を実行する前に 1000 文字で上限をかけます。
 `workspace/symbol` は任意の numeric `limit` / `maxResults` parameter を受け取り、1000 件までに
 clamp します。`textDocument/documentSymbol` は container metadata がある場合に階層化された
 `DocumentSymbol` children を返し、最後に受理した live buffer または index から最大 1000 件の

changelog.d/unreleased/5231.fixed.md

@@ -0,0 +1,21 @@
+---
+category: fixed
+issues:
+  - 5231
+affected:
+  - src/CodeIndex/Lsp/LspServer.cs
+  - src/CodeIndex/Lsp/LspServer.Protocol.cs
+  - src/CodeIndex/Lsp/LspServer.SymbolRequests.cs
+  - tests/CodeIndex.Tests/LspServerTests.cs
+  - DEVELOPER_GUIDE.md
+  - TESTING_GUIDE.md
+  - USER_GUIDE.md
+---
+
+## English
+
+- **LSP now rejects malformed JSON-RPC envelopes and invalid workspace-symbol query types (#5231)** — extending the protocol-boundary hardening from #4336, #4869, and #3128, the server now requires `jsonrpc: "2.0"` and a string `workspace/symbol.params.query` before lifecycle reservation, dispatch, or database access, while preserving valid empty queries.
+
+## 日本語
+
+- **LSP が不正な JSON-RPC envelope と workspace symbol query の型を拒否するようになりました (#5231)** — #4336、#4869、#3128 の protocol boundary hardening を拡張し、server は lifecycle reservation、dispatch、database access より前に `jsonrpc: "2.0"` と文字列の `workspace/symbol.params.query` を必須にしつつ、正当な空 query は引き続き受け付けます。

src/CodeIndex/Lsp/LspServer.Protocol.cs

@@ -149,13 +149,18 @@ private static string GetTextDocumentUri(JsonElement root)
         return uri;
     }
 
-    private static string? GetString(JsonElement root, params string[] path)
+    private static string GetRequiredString(JsonElement root, params string[] path)
     {
         if (!TryGet(root, out var value, path) || value.ValueKind != JsonValueKind.String)
-            return null;
-        return value.GetString();
+            throw new ArgumentException("A required string parameter is missing or invalid.");
+        return value.GetString()!;
     }
 
+    private static bool HasValidJsonRpcEnvelope(JsonElement root) =>
+        root.TryGetProperty("jsonrpc", out var jsonRpc)
+        && jsonRpc.ValueKind == JsonValueKind.String
+        && string.Equals(jsonRpc.GetString(), "2.0", StringComparison.Ordinal);
+
     private static bool? GetBool(JsonElement root, params string[] path)
     {
         if (!TryGet(root, out var value, path))

src/CodeIndex/Lsp/LspServer.SymbolRequests.cs

@@ -93,9 +93,7 @@ private SymbolResponse CreateWorkspaceSymbolResponse(
         bool createPartialItems,
         CancellationToken cancellationToken)
     {
-        var query = GetString(root, "params", "query");
-        if (query != null && query.Length > QueryLimits.MaxQueryLength)
-            throw new ArgumentException(QueryLimits.FormatQueryTooLongError());
+        var query = GetWorkspaceSymbolQuery(root);
 
         var limit = GetLimit(root, DefaultLimit, MaxWorkspaceSymbols, "params", "limit")
             ?? GetLimit(root, DefaultLimit, MaxWorkspaceSymbols, "params", "maxResults")
@@ -141,6 +139,14 @@ private SymbolResponse CreateWorkspaceSymbolResponse(
         return new SymbolResponse(array, [], array.Count, truncated);
     }
 
+    private static string GetWorkspaceSymbolQuery(JsonElement root)
+    {
+        var query = GetRequiredString(root, "params", "query");
+        if (query.Length > QueryLimits.MaxQueryLength)
+            throw new ArgumentException(QueryLimits.FormatQueryTooLongError());
+        return query;
+    }
+
     private IEnumerable<JsonNode> EnumerateWorkspaceSymbolItems(
         IReadOnlyList<SymbolResult> symbols,
         CancellationToken cancellationToken)