Enum ExtismError 

#[non_exhaustive]
pub enum ExtismError {
    InvalidPlugin(String),
    ManifestInvalid(String),
    Instantiate(String),
    CapabilityDenied {
        host_fn: String,
        capability: String,
    },
    OutputDecode(String),
    Ipc(IpcError),
    ResourceLimit(String),
    Internal(String),
}

Errors specific to the Extism loader.

Mirrors uni_plugin_wasm::WasmError in shape so the two loaders surface comparable failure modes despite their different ABIs.

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.

InvalidPlugin(String)

The supplied WASM bytes failed to parse or did not declare the expected Extism plugin shape (manifest export, function exports).

ManifestInvalid(String)

The plugin’s declared manifest did not pass validation (unknown ABI, missing required fields, capability conflict).

Instantiate(String)

Extism plugin instantiation failed.

CapabilityDenied

A capability-gated host function was invoked without the matching grant. Unlike the Component Model path (where the import is absent at the linker level), Extism enforces capability checks at the host-fn body — this variant carries the call that was blocked.

Fields

host_fn: String

Host function the plugin attempted to invoke.

capability: String

The capability the plugin would need.

OutputDecode(String)

The plugin’s output failed to decode under the expected wire format (JSON or MessagePack for control surfaces).

Ipc(IpcError)

Arrow IPC encode / decode failed across the wasm boundary. Distinct from Self::OutputDecode which is JSON / MessagePack for control surfaces.

ResourceLimit(String)

Wall-clock, fuel, or memory limit exceeded.

Internal(String)

Internal / unexpected error.

Trait Implementations

impl Debug for ExtismError

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

Formats the value using the given formatter.

impl Display for ExtismError

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

Formats the value using the given formatter.

impl Error for ExtismError

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<IpcError> for ExtismError

fn from(source: IpcError) -> Self

Converts to this type from the input type.

impl PoolResourceLimit for ExtismError

fn resource_limit(msg: String) -> Self

Construct a “resource limit exceeded” instance from a diagnostic message. Called when the pool’s max_instances is reached.