#![allow(clippy::wrong_self_convention)]
use std::error::Error as StdError;
use std::fmt;
use std::io::Error as IoError;
use std::net::AddrParseError;
use std::result::Result as StdResult;
use std::str::Utf8Error;
use std::string::String as StdString;
use std::sync::Arc;
/// Error type returned by `mlua` methods.
#[derive(Debug, Clone)]
#[non_exhaustive]
pub enum Error {
/// Syntax error while parsing Lua source code.
SyntaxError {
/// The error message as returned by Lua.
message: StdString,
/// `true` if the error can likely be fixed by appending more input to the source code.
///
/// This is useful for implementing REPLs as they can query the user for more input if this
/// is set.
incomplete_input: bool,
},
/// Lua runtime error, aka `LUA_ERRRUN`.
///
/// The Lua VM returns this error when a builtin operation is performed on incompatible types.
/// Among other things, this includes invoking operators on wrong types (such as calling or
/// indexing a `nil` value).
RuntimeError(StdString),
/// Lua memory error, aka `LUA_ERRMEM`
///
/// The Lua VM returns this error when the allocator does not return the requested memory, aka
/// it is an out-of-memory error.
MemoryError(StdString),
/// Lua garbage collector error, aka `LUA_ERRGCMM`.
///
/// The Lua VM returns this error when there is an error running a `__gc` metamethod.
#[cfg(any(feature = "lua53", feature = "lua52", feature = "lua-factorio", doc))]
#[cfg_attr(docsrs, doc(cfg(any(feature = "lua53", feature = "lua52", feature = "lua-factorio"))))]
GarbageCollectorError(StdString),
/// Potentially unsafe action in safe mode.
SafetyError(StdString),
/// Setting memory limit is not available.
///
/// This error can only happen when Lua state was not created by us and does not have the
/// custom allocator attached.
MemoryLimitNotAvailable,
/// Main thread is not available.
///
/// This error can only happen in Lua5.1/LuaJIT module mode, when module loaded within a coroutine.
/// These Lua versions does not have `LUA_RIDX_MAINTHREAD` registry key.
MainThreadNotAvailable,
/// A mutable callback has triggered Lua code that has called the same mutable callback again.
///
/// This is an error because a mutable callback can only be borrowed mutably once.
RecursiveMutCallback,
/// Either a callback or a userdata method has been called, but the callback or userdata has
/// been destructed.
///
/// This can happen either due to to being destructed in a previous __gc, or due to being
/// destructed from exiting a `Lua::scope` call.
CallbackDestructed,
/// Not enough stack space to place arguments to Lua functions or return values from callbacks.
///
/// Due to the way `mlua` works, it should not be directly possible to run out of stack space
/// during normal use. The only way that this error can be triggered is if a `Function` is
/// called with a huge number of arguments, or a rust callback returns a huge number of return
/// values.
StackError,
/// Too many arguments to `Function::bind`
BindError,
/// A Rust value could not be converted to a Lua value.
ToLuaConversionError {
/// Name of the Rust type that could not be converted.
from: &'static str,
/// Name of the Lua type that could not be created.
to: &'static str,
/// A message indicating why the conversion failed in more detail.
message: Option<StdString>,
},
/// A Lua value could not be converted to the expected Rust type.
FromLuaConversionError {
/// Name of the Lua type that could not be converted.
from: &'static str,
/// Name of the Rust type that could not be created.
to: &'static str,
/// A string containing more detailed error information.
message: Option<StdString>,
},
/// [`Thread::resume`] was called on an inactive coroutine.
///
/// A coroutine is inactive if its main function has returned or if an error has occurred inside
/// the coroutine.
///
/// [`Thread::status`] can be used to check if the coroutine can be resumed without causing this
/// error.
///
/// [`Thread::resume`]: crate::Thread::resume
/// [`Thread::status`]: crate::Thread::status
CoroutineInactive,
/// An [`AnyUserData`] is not the expected type in a borrow.
///
/// This error can only happen when manually using [`AnyUserData`], or when implementing
/// metamethods for binary operators. Refer to the documentation of [`UserDataMethods`] for
/// details.
///
/// [`AnyUserData`]: crate::AnyUserData
/// [`UserDataMethods`]: crate::UserDataMethods
UserDataTypeMismatch,
/// An [`AnyUserData`] borrow failed because it has been destructed.
///
/// This error can happen either due to to being destructed in a previous __gc, or due to being
/// destructed from exiting a `Lua::scope` call.
///
/// [`AnyUserData`]: crate::AnyUserData
UserDataDestructed,
/// An [`AnyUserData`] immutable borrow failed because it is already borrowed mutably.
///
/// This error can occur when a method on a [`UserData`] type calls back into Lua, which then
/// tries to call a method on the same [`UserData`] type. Consider restructuring your API to
/// prevent these errors.
///
/// [`AnyUserData`]: crate::AnyUserData
/// [`UserData`]: crate::UserData
UserDataBorrowError,
/// An [`AnyUserData`] mutable borrow failed because it is already borrowed.
///
/// This error can occur when a method on a [`UserData`] type calls back into Lua, which then
/// tries to call a method on the same [`UserData`] type. Consider restructuring your API to
/// prevent these errors.
///
/// [`AnyUserData`]: crate::AnyUserData
/// [`UserData`]: crate::UserData
UserDataBorrowMutError,
/// A [`MetaMethod`] operation is restricted (typically for `__gc` or `__metatable`).
///
/// [`MetaMethod`]: crate::MetaMethod
MetaMethodRestricted(StdString),
/// A [`MetaMethod`] (eg. `__index` or `__newindex`) has invalid type.
///
/// [`MetaMethod`]: crate::MetaMethod
MetaMethodTypeError {
method: StdString,
type_name: &'static str,
message: Option<StdString>,
},
/// A [`RegistryKey`] produced from a different Lua state was used.
///
/// [`RegistryKey`]: crate::RegistryKey
MismatchedRegistryKey,
/// A Rust callback returned `Err`, raising the contained `Error` as a Lua error.
CallbackError {
/// Lua call stack backtrace.
traceback: StdString,
/// Original error returned by the Rust code.
cause: Arc<Error>,
},
/// A Rust panic that was previously resumed, returned again.
///
/// This error can occur only when a Rust panic resumed previously was recovered
/// and returned again.
PreviouslyResumedPanic,
/// Serialization error.
#[cfg(feature = "serialize")]
#[cfg_attr(docsrs, doc(cfg(feature = "serialize")))]
SerializeError(StdString),
/// Deserialization error.
#[cfg(feature = "serialize")]
#[cfg_attr(docsrs, doc(cfg(feature = "serialize")))]
DeserializeError(StdString),
/// A custom error.
///
/// This can be used for returning user-defined errors from callbacks.
///
/// Returning `Err(ExternalError(...))` from a Rust callback will raise the error as a Lua
/// error. The Rust code that originally invoked the Lua code then receives a `CallbackError`,
/// from which the original error (and a stack traceback) can be recovered.
ExternalError(Arc<dyn StdError + Send + Sync>),
}
/// A specialized `Result` type used by `mlua`'s API.
pub type Result<T> = StdResult<T, Error>;
#[cfg(not(tarpaulin_include))]
impl fmt::Display for Error {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
match *self {
Error::SyntaxError { ref message, .. } => write!(fmt, "syntax error: {}", message),
Error::RuntimeError(ref msg) => write!(fmt, "runtime error: {}", msg),
Error::MemoryError(ref msg) => {
write!(fmt, "memory error: {}", msg)
}
#[cfg(any(feature = "lua53", feature = "lua52", feature = "lua-factorio"))]
Error::GarbageCollectorError(ref msg) => {
write!(fmt, "garbage collector error: {}", msg)
}
Error::SafetyError(ref msg) => {
write!(fmt, "safety error: {}", msg)
},
Error::MemoryLimitNotAvailable => {
write!(fmt, "setting memory limit is not available")
}
Error::MainThreadNotAvailable => {
write!(fmt, "main thread is not available in Lua 5.1")
}
Error::RecursiveMutCallback => write!(fmt, "mutable callback called recursively"),
Error::CallbackDestructed => write!(
fmt,
"a destructed callback or destructed userdata method was called"
),
Error::StackError => write!(
fmt,
"out of Lua stack, too many arguments to a Lua function or too many return values from a callback"
),
Error::BindError => write!(
fmt,
"too many arguments to Function::bind"
),
Error::ToLuaConversionError { from, to, ref message } => {
write!(fmt, "error converting {} to Lua {}", from, to)?;
match *message {
None => Ok(()),
Some(ref message) => write!(fmt, " ({})", message),
}
}
Error::FromLuaConversionError { from, to, ref message } => {
write!(fmt, "error converting Lua {} to {}", from, to)?;
match *message {
None => Ok(()),
Some(ref message) => write!(fmt, " ({})", message),
}
}
Error::CoroutineInactive => write!(fmt, "cannot resume inactive coroutine"),
Error::UserDataTypeMismatch => write!(fmt, "userdata is not expected type"),
Error::UserDataDestructed => write!(fmt, "userdata has been destructed"),
Error::UserDataBorrowError => write!(fmt, "userdata already mutably borrowed"),
Error::UserDataBorrowMutError => write!(fmt, "userdata already borrowed"),
Error::MetaMethodRestricted(ref method) => write!(fmt, "metamethod {} is restricted", method),
Error::MetaMethodTypeError { ref method, type_name, ref message } => {
write!(fmt, "metamethod {} has unsupported type {}", method, type_name)?;
match *message {
None => Ok(()),
Some(ref message) => write!(fmt, " ({})", message),
}
}
Error::MismatchedRegistryKey => {
write!(fmt, "RegistryKey used from different Lua state")
}
Error::CallbackError { ref cause, ref traceback } => {
writeln!(fmt, "callback error")?;
// Trace errors down to the root
let (mut cause, mut full_traceback) = (cause, None);
while let Error::CallbackError { cause: ref cause2, traceback: ref traceback2 } = **cause {
cause = cause2;
full_traceback = Some(traceback2);
}
if let Some(full_traceback) = full_traceback {
let traceback = traceback.trim_start_matches("stack traceback:");
let traceback = traceback.trim_start().trim_end();
// Try to find local traceback within the full traceback
if let Some(pos) = full_traceback.find(traceback) {
write!(fmt, "{}", &full_traceback[..pos])?;
writeln!(fmt, ">{}", &full_traceback[pos..].trim_end())?;
} else {
writeln!(fmt, "{}", full_traceback.trim_end())?;
}
} else {
writeln!(fmt, "{}", traceback.trim_end())?;
}
write!(fmt, "caused by: {}", cause)
}
Error::PreviouslyResumedPanic => {
write!(fmt, "previously resumed panic returned again")
}
#[cfg(feature = "serialize")]
Error::SerializeError(ref err) => {
write!(fmt, "serialize error: {}", err)
},
#[cfg(feature = "serialize")]
Error::DeserializeError(ref err) => {
write!(fmt, "deserialize error: {}", err)
},
Error::ExternalError(ref err) => write!(fmt, "{}", err),
}
}
}
impl StdError for Error {
fn source(&self) -> Option<&(dyn StdError + 'static)> {
match *self {
// An error type with a source error should either return that error via source or
// include that source's error message in its own Display output, but never both.
// https://blog.rust-lang.org/inside-rust/2021/07/01/What-the-error-handling-project-group-is-working-towards.html
// Given that we include source to fmt::Display implementation for `CallbackError`, this call returns nothing.
Error::CallbackError { .. } => None,
Error::ExternalError(ref err) => err.source(),
_ => None,
}
}
}
impl Error {
pub fn external<T: Into<Box<dyn StdError + Send + Sync>>>(err: T) -> Error {
Error::ExternalError(err.into().into())
}
}
pub trait ExternalError {
fn to_lua_err(self) -> Error;
}
impl<E: Into<Box<dyn StdError + Send + Sync>>> ExternalError for E {
fn to_lua_err(self) -> Error {
Error::external(self)
}
}
pub trait ExternalResult<T> {
fn to_lua_err(self) -> Result<T>;
}
impl<T, E> ExternalResult<T> for StdResult<T, E>
where
E: ExternalError,
{
fn to_lua_err(self) -> Result<T> {
self.map_err(|e| e.to_lua_err())
}
}
impl std::convert::From<AddrParseError> for Error {
fn from(err: AddrParseError) -> Self {
Error::external(err)
}
}
impl std::convert::From<IoError> for Error {
fn from(err: IoError) -> Self {
Error::external(err)
}
}
impl std::convert::From<Utf8Error> for Error {
fn from(err: Utf8Error) -> Self {
Error::external(err)
}
}
#[cfg(feature = "serialize")]
impl serde::ser::Error for Error {
fn custom<T: fmt::Display>(msg: T) -> Self {
Self::SerializeError(msg.to_string())
}
}
#[cfg(feature = "serialize")]
impl serde::de::Error for Error {
fn custom<T: fmt::Display>(msg: T) -> Self {
Self::DeserializeError(msg.to_string())
}
}