Use response files to index files if argument list exceeds maximum number of arguments

Sources/BuildSystemIntegration/BuildSettingsLogger.swift

@@ -48,7 +48,9 @@ package actor BuildSettingsLogger {
       """
 
     let chunks = splitLongMultilineMessage(message: log)
-    for (index, chunk) in chunks.enumerated() {
+    // Only print the first 100 chunks. If the argument list gets any longer, we don't want to spam the log too much.
+    // In practice, 100 chunks should be sufficient.
+    for (index, chunk) in chunks.enumerated().prefix(100) {
       logger.log(
         level: level,
         """

Sources/SKTestSupport/BuildServerTestProject.swift

@@ -65,6 +65,7 @@ package class BuildServerTestProject: MultiFileTestProject {
     buildServerConfigLocation: RelativeFileLocation = ".bsp/sourcekit-lsp.json",
     buildServer: String,
     options: SourceKitLSPOptions? = nil,
+    enableBackgroundIndexing: Bool = false,
     testName: String = #function
   ) async throws {
     var files = files
@@ -92,6 +93,7 @@ package class BuildServerTestProject: MultiFileTestProject {
     try await super.init(
       files: files,
       options: options,
+      enableBackgroundIndexing: enableBackgroundIndexing,
       testName: testName
     )
   }

Sources/SKTestSupport/INPUTS/AbstractBuildServer.py

@@ -70,6 +70,8 @@ def handle_message(self, message: Dict[str, object]) -> Optional[Dict[str, objec
             return self.initialized(params)
         elif method == "build/shutdown":
             return self.shutdown(params)
+        elif method == "buildTarget/prepare":
+            return self.buildtarget_prepare(params)
         elif method == "buildTarget/sources":
             return self.buildtarget_sources(params)
         elif method == "textDocument/registerForChanges":
@@ -80,6 +82,8 @@ def handle_message(self, message: Dict[str, object]) -> Optional[Dict[str, objec
             return self.workspace_did_change_watched_files(params)
         elif method == "workspace/buildTargets":
             return self.workspace_build_targets(params)
+        elif method == "workspace/waitForBuildSystemUpdates":
+            return self.workspace_waitForBuildSystemUpdates(params)
 
         # ignore other notifications
         if "id" in message:
@@ -120,10 +124,8 @@ def initialize(self, request: Dict[str, object]) -> Dict[str, object]:
             "version": "0.1",
             "bspVersion": "2.0",
             "rootUri": "blah",
-            "capabilities": {"languageIds": ["a", "b"]},
+            "capabilities": {"languageIds": ["swift", "c", "cpp", "objective-c", "objective-c"]},
             "data": {
-                "indexDatabasePath": "some/index/db/path",
-                "indexStorePath": "some/index/store/path",
                 "sourceKitOptionsProvider": True,
             },
         }
@@ -144,6 +146,11 @@ def textdocument_sourcekitoptions(
     def shutdown(self, request: Dict[str, object]) -> Dict[str, object]:
         return {}
 
+    def buildtarget_prepare(self, request: Dict[str, object]) -> Dict[str, object]:
+        raise RequestError(
+            code=-32601, message=f"'buildTarget/prepare' not implemented"
+        )
+
     def buildtarget_sources(self, request: Dict[str, object]) -> Dict[str, object]:
         raise RequestError(
             code=-32601, message=f"'buildTarget/sources' not implemented"
@@ -157,6 +164,9 @@ def workspace_build_targets(self, request: Dict[str, object]) -> Dict[str, objec
             code=-32601, message=f"'workspace/buildTargets' not implemented"
         )
 
+    def workspace_waitForBuildSystemUpdates(self, request: Dict[str, object]) -> Dict[str, object]:
+        return {}
+
 
 class LegacyBuildServer(AbstractBuildServer):
     def send_sourcekit_options_changed(self, uri: str, options: List[str]):

Sources/SemanticIndex/UpdateIndexStoreTaskDescription.swift

@@ -24,6 +24,7 @@ import TSCExtensions
 import struct TSCBasic.AbsolutePath
 import class TSCBasic.Process
 import struct TSCBasic.ProcessResult
+import enum TSCBasic.SystemError
 #else
 import BuildServerProtocol
 import BuildSystemIntegration
@@ -38,6 +39,11 @@ import TSCExtensions
 import struct TSCBasic.AbsolutePath
 import class TSCBasic.Process
 import struct TSCBasic.ProcessResult
+import enum TSCBasic.SystemError
+#endif
+
+#if os(Windows)
+import WinSDK
 #endif
 
 private let updateIndexStoreIDForLogging = AtomicUInt32(initialValue: 1)
@@ -415,7 +421,7 @@ package struct UpdateIndexStoreTaskDescription: IndexTaskDescription {
     let result: ProcessResult
     do {
       result = try await withTimeout(timeout) {
-        try await Process.run(
+        try await Process.runUsingResponseFileIfTooManyArguments(
           arguments: processArguments,
           workingDirectory: workingDirectory,
           outputRedirection: .stream(
@@ -464,3 +470,66 @@ package struct UpdateIndexStoreTaskDescription: IndexTaskDescription {
     }
   }
 }
+
+fileprivate extension Process {
+  /// Run a process with the given arguments. If the number of arguments exceeds the maximum number of arguments allows,
+  /// create a response file and use it to pass the arguments.
+  static func runUsingResponseFileIfTooManyArguments(
+    arguments: [String],
+    workingDirectory: AbsolutePath?,
+    outputRedirection: OutputRedirection = .collect(redirectStderr: false)
+  ) async throws -> ProcessResult {
+    do {
+      return try await Process.run(
+        arguments: arguments,
+        workingDirectory: workingDirectory,
+        outputRedirection: outputRedirection
+      )
+    } catch {
+      let argumentListTooLong: Bool
+      #if os(Windows)
+      if let error = error as? CocoaError {
+        argumentListTooLong =
+          error.underlyingErrors.contains(where: {
+            return ($0 as NSError).domain == "org.swift.Foundation.WindowsError"
+              && ($0 as NSError).code == ERROR_FILENAME_EXCED_RANGE
+          })
+      } else {
+        argumentListTooLong = false
+      }
+      #else
+      if case SystemError.posix_spawn(E2BIG, _) = error {
+        argumentListTooLong = true
+      } else {
+        argumentListTooLong = false
+      }
+      #endif
+
+      guard argumentListTooLong else {
+        throw error
+      }
+
+      logger.debug("Argument list is too long. Using response file.")
+      let responseFile = FileManager.default.temporaryDirectory.appendingPathComponent(
+        "index-response-file-\(UUID()).txt"
+      )
+      defer {
+        orLog("Failed to remove temporary response file") {
+          try FileManager.default.removeItem(at: responseFile)
+        }
+      }
+      FileManager.default.createFile(atPath: try responseFile.filePath, contents: nil)
+      let handle = try FileHandle(forWritingTo: responseFile)
+      for argument in arguments.dropFirst() {
+        handle.write(Data((argument.spm_shellEscaped() + "\n").utf8))
+      }
+      try handle.close()
+
+      return try await Process.run(
+        arguments: arguments.prefix(1) + ["@\(responseFile.filePath)"],
+        workingDirectory: workingDirectory,
+        outputRedirection: outputRedirection
+      )
+    }
+  }
+}

Sources/SourceKitLSP/Swift/DocumentFormatting.swift

@@ -23,7 +23,6 @@ import TSCExtensions
 
 import struct TSCBasic.AbsolutePath
 import class TSCBasic.Process
-import func TSCBasic.withTemporaryFile
 #else
 import Foundation
 import LanguageServerProtocol
@@ -37,7 +36,6 @@ import TSCExtensions
 
 import struct TSCBasic.AbsolutePath
 import class TSCBasic.Process
-import func TSCBasic.withTemporaryFile
 #endif
 
 fileprivate extension String {

Tests/SourceKitLSPTests/BackgroundIndexingTests.swift

@@ -2040,6 +2040,88 @@ final class BackgroundIndexingTests: XCTestCase {
       return hoverAfterAddingDependencyDeclaration != nil
     }
   }
+
+  func testUseResponseFileIfTooManyArguments() async throws {
+    // The build system returns too many arguments to fit them into a command line invocation, so we need to use a
+    // response file to invoke the indexer.
+
+    let project = try await BuildServerTestProject(
+      files: [
+        // File name contains a space to ensure we escape it in the response file.
+        "Test File.swift": """
+        func 1️⃣myTestFunc() {}
+        """
+      ],
+      buildServer: """
+        class BuildServer(AbstractBuildServer):
+
+          def initialize(self, request: Dict[str, object]) -> Dict[str, object]:
+            return {
+              "displayName": "test server",
+              "version": "0.1",
+              "bspVersion": "2.0",
+              "rootUri": "blah",
+              "capabilities": {"languageIds": ["swift", "c", "cpp", "objective-c", "objective-c"]},
+              "data": {
+                "indexDatabasePath": r"$TEST_DIR/index-db",
+                "indexStorePath": r"$TEST_DIR/index",
+                "prepareProvider": True,
+                "sourceKitOptionsProvider": True,
+              },
+            }
+
+          def workspace_build_targets(self, request: Dict[str, object]) -> Dict[str, object]:
+            return {
+              "targets": [
+                {
+                  "id": {"uri": "bsp://dummy"},
+                  "tags": [],
+                  "languageIds": [],
+                  "dependencies": [],
+                  "capabilities": {},
+                }
+              ]
+            }
+
+          def buildtarget_sources(self, request: Dict[str, object]) -> Dict[str, object]:
+            return {
+              "items": [
+                {
+                  "target": {"uri": "bsp://dummy"},
+                  "sources": [
+                    {"uri": "$TEST_DIR_URL/Test.swift", "kind": 1, "generated": False}
+                  ],
+                }
+              ]
+            }
+
+          def textdocument_sourcekitoptions(self, request: Dict[str, object]) -> Dict[str, object]:
+            return {
+              "compilerArguments": [r"$TEST_DIR/Test File.swift", "-DDEBUG", $SDK_ARGS] + \
+                [f"-DTHIS_IS_AN_OPTION_THAT_CONTAINS_MANY_BYTES_{i}" for i in range(0, 50_000)]
+            }
+
+          def buildtarget_prepare(self, request: Dict[str, object]) -> Dict[str, object]:
+            return {}
+        """,
+      enableBackgroundIndexing: true
+    )
+    try await project.testClient.send(PollIndexRequest())
+
+    let symbols = try await project.testClient.send(WorkspaceSymbolsRequest(query: "myTestFunc"))
+    XCTAssertEqual(
+      symbols,
+      [
+        .symbolInformation(
+          SymbolInformation(
+            name: "myTestFunc()",
+            kind: .function,
+            location: try project.location(from: "1️⃣", to: "1️⃣", in: "Test File.swift")
+          )
+        )
+      ]
+    )
+  }
 }
 
 extension HoverResponseContents {