{"record":{"id":"e8af0e1b739013d6","repo":"oraios/serena","slug":"failed-to-initialize-f-language-server-for-self","errorCode":null,"errorMessage":"Failed to initialize F# language server for {self.repository_root_path}: {e}","messagePattern":"Failed to initialize F# language server for (.+?): (.+?)","errorType":"exception","errorClass":"SolidLSPException","httpStatus":null,"severity":"error","filePath":"src/solidlsp/language_servers/fsharp_language_server.py","lineNumber":422,"sourceCode":"        self.server.on_request(\"window/workDoneProgress/create\", handle_work_done_progress_create)\n\n        log.info(\"Starting FsAutoComplete F# language server process\")\n\n        try:\n            self.server.start()\n        except Exception as e:\n            log.error(f\"Failed to start F# language server process: {e}\")\n            raise SolidLSPException(f\"Failed to start F# language server: {e}\")\n\n        # Send initialization\n        initialize_params = self._create_initialize_params()\n\n        log.info(\"Sending initialize request to F# language server\")\n        try:\n            self.server.send.initialize(initialize_params)\n            log.debug(\"Received initialize response from F# language server\")\n        except Exception as e:\n            raise SolidLSPException(f\"Failed to initialize F# language server for {self.repository_root_path}: {e}\") from e\n\n        # Complete initialization\n        self.server.notify.initialized({})\n\n        log.info(\"F# language server initialized successfully\")\n\n    @override\n    def _get_wait_time_for_cross_file_referencing(self) -> float:\n        \"\"\"\n        F# projects can be large and may need more time for cross-file analysis.\n        \"\"\"\n        return 15.0  # 15 seconds should be sufficient for most F# projects\n","sourceCodeStart":404,"sourceCodeEnd":435,"githubUrl":"https://github.com/oraios/serena/blob/7fcbca7e62555ec2287ddb2f083caee805848ea6/src/solidlsp/language_servers/fsharp_language_server.py#L404-L435","documentation":"SolidLSPException raised when the LSP 'initialize' request sent to the F# language server (fsautocomplete) fails or times out. The library wraps any exception from self.server.send.initialize() to add context about which repository root failed. It indicates the F# server process started but never completed the LSP handshake.","triggerScenarios":"Calling _start_server for an F# project when the fsautocomplete process crashes during startup, the initialize request times out, or the server writes an invalid JSON-RPC response.","commonSituations":"Broken .NET/F# toolchain installation, incompatible fsautocomplete version, corrupted project files (fsproj) that crash the compiler service on startup, or resource exhaustion killing the server process mid-initialize.","solutions":["Run `dotnet tool list -g` / reinstall fsautocomplete (`dotnet tool install --global fsautocomplete`) and verify `fsautocomplete --version` works","Verify the target F# project builds (`dotnet build`) — broken fsproj/sln files crash the server during initialize","Increase the LSP startup timeout in the environment to rule out slow first-run .NET JIT/restore","Reproduce manually by launching fsautocomplete and sending an initialize request; inspect stderr for the underlying exception"],"exampleFix":"// before (no version pin, broken tool)\ndotnet tool install --global fsautocomplete\n// after (reinstall clean and verify)\ndotnet tool uninstall --global fsautocomplete\ndotnet tool install --global fsautocomplete\nfsautocomplete --version","handlingStrategy":"try-catch","validationCode":"import shutil, subprocess\ndef ensure_fsautocomplete_ready():\n    if not shutil.which('fsautocomplete'):\n        raise FileNotFoundError('fsautocomplete not on PATH')\n    subprocess.run(['dotnet', '--version'], check=True, capture_output=True)","typeGuard":"def is_fsharp_project(root: str) -> bool:\n    import os\n    return os.path.isdir(root) and any(f.endswith(('.fsproj', '.sln')) for f in os.listdir(root))","tryCatchPattern":"from solidlsp import SolidLSPException\ntry:\n    ls = FsharpLanguageServer(repo_root, ...)\n    ls.start()\nexcept SolidLSPException as e:\n    log.error(f'F# LS init failed: {e}')  # inspect underlying Exception via e.__cause__","preventionTips":["Verify `dotnet build` succeeds on the target project before starting the LS","Keep fsautocomplete updated to a version matching your .NET SDK","Allow generous startup timeout on first run (NuGet restore + JIT)","Check fsautocomplete can start standalone before integrating"],"tags":["fsharp","lsp","initialization","language-server"],"backgroundTag":"lsp-server-initialization-failed","analyzedSha":"7fcbca7e62555ec2287ddb2f083caee805848ea6","analyzedAt":"2026-08-29T00:04:09.619Z","schemaVersion":2},"datasetVersion":"2026-08-29T02:17:18.158Z"}