Cap pattern config discovery candidates

DEVELOPER_GUIDE.md

@@ -2048,9 +2048,10 @@ Downstream users can add lightweight language support without rebuilding
   entries;
 - regex-backed symbol patterns are read from `.cdidx/patterns/*.yaml` and
   `~/.config/cdidx/patterns/*.yaml`; sidecars must be regular files under
-  non-symlink pattern directories, each file is capped at 64 KiB / 128 rules,
-  the process loads at most 128 configured rules total, and regex matches use a
-  100 ms timeout;
+  non-symlink pattern directories, discovery accepts at most 128 candidates per
+  pattern directory, each file is capped at 64 KiB / 128 rules, the process
+  loads at most 128 configured rules total, and regex matches use a 100 ms
+  timeout;
 - `cdidx test-extractor --language <lang> --file <path> --json` runs symbol
   extraction without building an index, and `--expect-symbols <json>` compares
   the extracted JSON to a fixture. The source and expectation files are capped
@@ -3632,8 +3633,9 @@ Cloud セッションは開発ループの中で `dotnet build` にフォール
   祖先の `.cdidx-langmap.yaml` から読み込まれ、workspace 側が user 側を上書きします。
 - regex ベースのシンボルパターンは `.cdidx/patterns/*.yaml` と
   `~/.config/cdidx/patterns/*.yaml` から読み込まれます。sidecar は symlink ではない
-  pattern directory 配下の通常ファイルのみが対象で、各ファイルは 64 KiB / 128 ルール、
-  プロセス全体では configured rule 128 件に制限され、regex match には 100 ms の timeout が付きます。
+  pattern directory 配下の通常ファイルのみが対象で、探索候補は pattern directory ごとに
+  128 件まで、各ファイルは 64 KiB / 128 ルール、プロセス全体では configured rule 128 件に制限され、
+  regex match には 100 ms の timeout が付きます。
 - `cdidx test-extractor --language <lang> --file <path> --json` は index を作らずに
   symbol extraction だけを実行し、`--expect-symbols <json>` で fixture JSON と比較できます。
   source と expectation file はそれぞれ 4 MiB に制限されます。

README.md

@@ -81,8 +81,9 @@ Custom language loops can stay out of tree: put extension aliases in
 and run `cdidx test-extractor --language <lang> --file <path> --json` to test
 an extractor fixture without building a full index. `test-extractor` source and
 `--expect-symbols` files are capped at 4 MiB each. Pattern sidecars are
-limited to regular files under non-symlink pattern directories, size/count
-bounded per file and per process, and regex matches are time-limited. See
+limited to regular files under non-symlink pattern directories, discovery is
+capped per directory, size/count is bounded per file and per process, and regex
+matches are time-limited. See
 [Custom Language Extraction](DEVELOPER_GUIDE.md#custom-language-extraction).
 
 After the first command, use these cues and follow-up commands:
@@ -388,7 +389,7 @@ list metadata ごとに grouped されるため usage error で拒否します
 `cdidx test-extractor --language <lang> --file <path> --json` で full index を作らずに
 extractor fixture を確認できます。`test-extractor` の source と `--expect-symbols`
 ファイルはそれぞれ 4 MiB に制限されます。pattern sidecar は symlink ではない pattern directory
-配下の通常ファイルだけが対象で、size / count は file 単位と process 単位で制限され、
+配下の通常ファイルだけが対象で、探索候補数は directory 単位、size / count は file 単位と process 単位で制限され、
 regex match には timeout が付きます。詳細は
 [Custom Language Extraction](DEVELOPER_GUIDE.md#custom-language-extraction) を参照してください。
 

changelog.d/unreleased/3051.security.md

@@ -0,0 +1,18 @@
+---
+category: security
+issues:
+  - 3051
+affected:
+  - src/CodeIndex/Indexer/Extensibility/ExtractorPluginRegistry.cs
+  - tests/CodeIndex.Tests/SymbolExtractorConfiguredPatternTests.cs
+  - README.md
+  - DEVELOPER_GUIDE.md
+---
+
+## English
+
+- **Pattern config discovery is now streamed and capped per directory (#3051)** — `cdidx` now streams `.yaml` and `.yml` pattern sidecar discovery, accepts at most 128 pattern config candidates per directory, and emits a diagnostic when the directory cap is reached.
+
+## 日本語
+
+- **pattern config の探索を streaming 化し directory ごとの上限を追加しました (#3051)** — `cdidx` は `.yaml` / `.yml` の pattern sidecar 探索を streaming で行い、pattern config 候補を directory ごとに最大 128 件まで受け付け、上限に達した場合は diagnostic を出力します。

src/CodeIndex/Indexer/Extensibility/ExtractorPluginRegistry.cs

@@ -17,6 +17,7 @@ public static class ExtractorPluginRegistry
     internal const int MaxPatternRulesPerConfig = 128;
     internal const int MaxPatternRulesTotal = 128;
     internal const int MaxPatternRegexLength = 4096;
+    internal const int MaxPatternConfigCandidatesPerDirectory = 128;
     internal const int MaxPluginAssemblyCandidatesPerDirectory = 128;
     internal const int MaxPluginAssemblyCandidatesTotal = 256;
     internal const long MaxPluginAssemblyBytes = 64 * 1024 * 1024;
@@ -27,6 +28,7 @@ public static class ExtractorPluginRegistry
     private static readonly Dictionary<string, IReferenceExtractor> ReferenceExtractors = new(StringComparer.Ordinal);
     private static readonly HashSet<string> LoadedPluginAssemblyPaths = new(StringComparer.OrdinalIgnoreCase);
     private static readonly HashSet<string> LoadedPatternConfigPaths = new(StringComparer.OrdinalIgnoreCase);
+    private static readonly IReadOnlyList<string> PatternConfigSearchPatterns = ["*.yaml", "*.yml"];
     private static readonly List<ExtractorRegistryDiagnostic> Diagnostics = [];
     private const int DiagnosticLimit = 20;
     private static int pluginAssemblyCount;
@@ -166,6 +168,9 @@ internal static IReadOnlyList<string> EnumeratePluginAssemblyPathsForTests(strin
     internal static IReadOnlyList<string> EnumeratePluginAssemblyPathsForTests(IReadOnlyList<string> directories)
         => EnumeratePluginAssemblyPaths(directories).ToArray();
 
+    internal static IReadOnlyList<string> EnumeratePatternConfigPathsFromDirectoryForTests(string directory)
+        => EnumeratePatternConfigPathsFromDirectory(directory, workspaceRoot: null).ToArray();
+
     internal static void LoadPluginAssembliesForTests(IReadOnlyList<string> directories)
         => LoadPluginAssemblies(directories);
 
@@ -360,27 +365,58 @@ private static IEnumerable<string> EnumeratePatternConfigPathsFromDirectory(stri
         if (!Directory.Exists(directory) || !PatternDirectoryIsSafe(directory, workspaceRoot))
             yield break;
 
-        foreach (var path in EnumeratePatternFiles(directory, "*.yaml"))
-            yield return path;
-        foreach (var path in EnumeratePatternFiles(directory, "*.yml"))
-            yield return path;
+        var directoryCandidates = 0;
+        foreach (var searchPattern in PatternConfigSearchPatterns)
+        {
+            using var enumerator = TryEnumeratePatternFiles(directory, searchPattern);
+            if (enumerator == null)
+                continue;
+
+            while (TryMoveNextPatternFile(directory, enumerator, out var path))
+            {
+                if (directoryCandidates >= MaxPatternConfigCandidatesPerDirectory)
+                {
+                    ReportPatternDirectorySkipped(
+                        directory,
+                        $"too many pattern config candidates (maximum {MaxPatternConfigCandidatesPerDirectory} per directory)");
+                    yield break;
+                }
+
+                directoryCandidates++;
+                yield return path;
+            }
+        }
     }
 
-    private static IEnumerable<string> EnumeratePatternFiles(string directory, string searchPattern)
+    private static IEnumerator<string>? TryEnumeratePatternFiles(string directory, string searchPattern)
     {
-        string[] paths;
         try
         {
-            paths = Directory.GetFiles(directory, searchPattern, SearchOption.TopDirectoryOnly);
+            return Directory.EnumerateFiles(directory, searchPattern, SearchOption.TopDirectoryOnly).GetEnumerator();
         }
         catch (Exception ex) when (ex is IOException or UnauthorizedAccessException)
         {
             ReportPatternDirectoryRejected(directory, "could not enumerate pattern directory");
-            yield break;
+            return null;
         }
+    }
 
-        foreach (var path in paths)
-            yield return path;
+    private static bool TryMoveNextPatternFile(string directory, IEnumerator<string> enumerator, out string patternPath)
+    {
+        patternPath = string.Empty;
+        try
+        {
+            if (!enumerator.MoveNext())
+                return false;
+
+            patternPath = enumerator.Current;
+            return true;
+        }
+        catch (Exception ex) when (ex is IOException or UnauthorizedAccessException)
+        {
+            ReportPatternDirectoryRejected(directory, "could not enumerate pattern directory");
+            return false;
+        }
     }
 
     private static bool PatternDirectoryIsSafe(string directory, string? workspaceRoot)
@@ -547,6 +583,18 @@ private static void ReportPatternDirectoryRejected(string path, string reason)
             countsAsSkippedFile: false);
     }
 
+    private static void ReportPatternDirectorySkipped(string path, string reason)
+    {
+        Console.Error.WriteLine($"[cdidx] Skipped pattern directory '{DiagnosticSanitizer.ForPath(path)}': {DiagnosticSanitizer.ForMessage(reason)}.");
+        RecordDiagnostic(
+            "pattern_directory",
+            path,
+            typeName: null,
+            severity: "skipped",
+            $"Pattern directory skipped: {reason}.",
+            countsAsSkippedFile: false);
+    }
+
     private static void ReportPluginDirectorySkipped(string path, string reason)
     {
         RecordDiagnostic(

tests/CodeIndex.Tests/SymbolExtractorConfiguredPatternTests.cs

@@ -53,6 +53,41 @@ public void EnumeratePluginAssemblyPaths_UsesExplicitProjectRootForWorkspacePlug
         }
     }
 
+    [Fact]
+    public void EnumeratePatternConfigPathsFromDirectory_CapsCandidatesAcrossExtensionsWithDiagnostic()
+    {
+        lock (TestConsoleLock.Gate)
+        {
+            var tempDir = Path.Combine(Path.GetTempPath(), $"cdidx_patterns_candidate_cap_{Guid.NewGuid():N}");
+            try
+            {
+                var patternDir = Path.Combine(tempDir, ".cdidx", "patterns");
+                Directory.CreateDirectory(patternDir);
+                for (var i = 0; i < ExtractorPluginRegistry.MaxPatternConfigCandidatesPerDirectory; i++)
+                    File.WriteAllText(Path.Combine(patternDir, $"candidate{i:D3}.yaml"), string.Empty);
+                File.WriteAllText(Path.Combine(patternDir, "overflow.yml"), string.Empty);
+                ExtractorPluginRegistry.ResetForTests();
+
+                IReadOnlyList<string> paths = Array.Empty<string>();
+                var stderr = ConsoleCapture.CaptureError(() =>
+                {
+                    paths = ExtractorPluginRegistry.EnumeratePatternConfigPathsFromDirectoryForTests(patternDir);
+                });
+
+                Assert.Equal(ExtractorPluginRegistry.MaxPatternConfigCandidatesPerDirectory, paths.Count);
+                Assert.DoesNotContain(paths, path => Path.GetFileName(path) == "overflow.yml");
+                Assert.Contains("Skipped pattern directory", stderr, StringComparison.Ordinal);
+                Assert.Contains("too many pattern config candidates", stderr, StringComparison.Ordinal);
+            }
+            finally
+            {
+                ExtractorPluginRegistry.ResetForTests();
+                if (Directory.Exists(tempDir))
+                    Directory.Delete(tempDir, recursive: true);
+            }
+        }
+    }
+
     [Fact]
     public void Extract_ConfiguredPatternYaml_RejectsInvalidRegexWithDiagnostic()
     {