Enum Error 

#[non_exhaustive]
pub enum Error {
    LspInitFailed {
        message: String,
    },
    LspServerError {
        code: i32,
        message: String,
        data: Option<Value>,
    },
    McpServer(String),
    DocumentNotFound(PathBuf),
    NoServerForLanguage(String),
    NoServerForTool {
        language_id: String,
        tool: ToolKind,
    },
    ServerInitializing {
        server_id: ServerId,
    },
    WorkspaceServersInitializing,
    NoServerConfigured,
    NoServerForWorkspaceTool {
        tool: ToolKind,
    },
    Config(String),
    ConfigNotFound(PathBuf),
    InvalidConfig(String),
    Io(Error),
    Json(Error),
    TomlDe(Error),
    TomlSer(Error),
    Transport(String),
    Timeout(u64),
    Shutdown,
    ServerSpawnFailed {
        command: String,
        source: Error,
    },
    LspProtocolError(String),
    InvalidUri(String),
    EncodingError(String),
    ServerTerminated,
    ServerUnavailable {
        server_id: ServerId,
        reason: String,
    },
    InvalidToolParams(String),
    FileIo {
        path: PathBuf,
        source: Error,
    },
    PathOutsideWorkspace(PathBuf),
    DocumentLimitExceeded {
        current: usize,
        max: usize,
    },
    FileSizeLimitExceeded {
        size: u64,
        max: u64,
    },
    PartialServerInit {
        failed_count: usize,
        total_count: usize,
        failures: Vec<ServerSpawnFailure>,
    },
    AllServersFailedToInit {
        count: usize,
        failures: Vec<ServerSpawnFailure>,
    },
    NoServersAvailable(String),
    CapabilityNotSupported {
        server_id: ServerId,
        capability: &'static str,
    },
}

The main error type for mcpls-core operations.

This enum is #[non_exhaustive]: downstream crates that match on it must include a wildcard arm. New variants (such as Error::ServerInitializing) can then be added without further breaking changes.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

LspInitFailed

LSP server failed to initialize.

Fields

message: String

Description of the initialization failure.

LspServerError

LSP server returned an error response.

Fields

code: i32

JSON-RPC error code.

message: String

Error message from the server.

data: Option<Value>

Optional additional data from the JSON-RPC error object.

McpServer(String)

MCP server error.

DocumentNotFound(PathBuf)

Document was not found or could not be opened.

NoServerForLanguage(String)

No LSP server configured for the given language.

NoServerForTool

A server is configured for the language, but no server claims this specific tool (either no server lists it in handles and there is no catch-all, or the server that claimed it failed to spawn with no live catch-all to rebind to).

Fields

language_id: String

Language ID the request was for.

tool: ToolKind

Tool that no server claims.

ServerInitializing

LSP server for the language is configured but still initializing.

Fields

server_id: ServerId

Routing identity of the server that has not yet registered.

WorkspaceServersInitializing

A workspace-wide tool (one with no file to resolve a language from, e.g. workspace_symbol_search) could not be routed because at least one expected LSP server has not registered yet. Unlike Error::ServerInitializing, resolution never narrowed down to a single candidate server, so no server_id is available.

NoServerConfigured

No LSP server is currently configured.

NoServerForWorkspaceTool

At least one server is configured somewhere in the workspace, but none of them claims a workspace-wide tool that has no file to resolve a language from (e.g. workspace_symbol_search). The language-less counterpart of Error::NoServerForTool.

Fields

tool: ToolKind

Tool that no server claims anywhere in the workspace.

Config(String)

Configuration error.

ConfigNotFound(PathBuf)

Configuration file not found.

InvalidConfig(String)

Invalid configuration format.

Io(Error)

I/O error.

Json(Error)

JSON serialization/deserialization error.

TomlDe(Error)

TOML deserialization error.

TomlSer(Error)

TOML serialization error.

Transport(String)

LSP client transport error.

Timeout(u64)

Request timeout.

Shutdown

Server shutdown requested.

ServerSpawnFailed

LSP server failed to spawn.

Fields

command: String

Command that failed to spawn.

source: Error

Underlying IO error.

LspProtocolError(String)

LSP protocol error during message parsing.

InvalidUri(String)

Invalid URI format.

EncodingError(String)

Position encoding error.

ServerTerminated

Server process terminated unexpectedly.

ServerUnavailable

A crashed server could not be automatically respawned.

Distinct from Self::ServerTerminated so a caller (or a log reader) can tell “the connection just died” apart from “mcpls tried to bring it back and could not” – e.g. no respawn config was ever registered for it, or it is crash-looping and is being backed off.

Fields

server_id: ServerId

Routing identity of the server that could not be respawned.

reason: String

Human-readable reason the respawn did not proceed.

InvalidToolParams(String)

Invalid tool parameters provided.

FileIo

File I/O error occurred.

Fields

path: PathBuf

Path to the file.

source: Error

Underlying I/O error.

PathOutsideWorkspace(PathBuf)

Path is outside allowed workspace boundaries.

DocumentLimitExceeded

Document limit exceeded.

Fields

current: usize

Current number of documents.

max: usize

Maximum allowed documents.

FileSizeLimitExceeded

File size limit exceeded.

Fields

size: u64

Actual file size.

max: u64

Maximum allowed size.

PartialServerInit

Partial server initialization - some servers failed but at least one succeeded.

Fields

failed_count: usize

Number of servers that failed.

total_count: usize

Total number of configured servers.

failures: Vec<ServerSpawnFailure>

Details of each failure.

AllServersFailedToInit

All configured LSP servers failed to initialize.

Fields

count: usize

Number of servers that were configured.

failures: Vec<ServerSpawnFailure>

Details of each failure.

NoServersAvailable(String)

No LSP servers available (none configured or all failed).

CapabilityNotSupported

The server routed for this request does not advertise support for the requested LSP capability (e.g. no renameProvider in its ServerCapabilities).

Fields

server_id: ServerId

Routing identity of the server that lacks the capability.

capability: &'static str

Name of the missing LSP capability field (e.g. "renameProvider").

Trait Implementations

impl Debug for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Error

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.