pub struct Error {
    pub profile: Option<Profile>,
    pub metadata: Option<Metadata>,
    pub path: Vec<String, Global>,
    pub kind: Kind,
    /* private fields */
}
Expand description

An error that occured while producing data or extracting a configuration.

Constructing Errors

An Error will generally be constructed indirectly via its implementations of serde’s de::Error and ser::Error, that is, as a result of serialization or deserialization errors. When implementing Provider, however, it may be necessary to construct an Error directly.

Broadly, there are two ways to construct an Error:

  • Via an error message, since Error impls From<String>:

    use figment::Error;
    
    Error::from("whoops, something went wrong!".to_string());
  • Via a Kind, since Error impls From<Kind>:

    use figment::{error::{Error, Kind}, value::Value};
    
    let value = Value::serialize(&100).unwrap();
    if !value.as_str().is_some() {
        let kind = Kind::InvalidType(value.to_actual(), "string".into());
        let error = Error::from(kind);
    }

As always, ? can be used to automatically convert into an Error using the available From implementations:

use std::fs::File;

fn try_read() -> Result<(), figment::Error> {
    let x = File::open("/tmp/foo.boo").map_err(|e| e.to_string())?;
    Ok(())
}

Display

By default, Error uses all of the available information about the error, including the Metadata, path, and profile to display a message that resembles the following, where $ is error. for some error: Error:

$kind: `$metadata.interpolate($path)` in $($metadata.sources())*

Concretely, such an error may look like:

invalid type: found sequence, expected u16: `staging.port` in TOML file Config.toml

Iterator

An Error may contain more than one error. To process all errors, iterate over an Error:

fn with_error(error: figment::Error) {
    for error in error {
        println!("error: {}", error);
    }
}

Fields

profile: Option<Profile>

The profile that was selected when the error occured, if any.

metadata: Option<Metadata>

The metadata for the provider of the value that errored, if known.

path: Vec<String, Global>

The path to the configuration key that errored, if known.

kind: Kind

The error kind.

Implementations

Returns true if the error’s kind is MissingField.

Example
use figment::error::{Error, Kind};

let error = Error::from(Kind::MissingField("path".into()));
assert!(error.missing());

Append the string path to the error’s path.

Example
use figment::Error;

let error = Error::from("an error message".to_string())
    .with_path("some_path");

Returns the number of errors represented by self.

Example
use figment::{Figment, providers::{Format, Toml}};

figment::Jail::expect_with(|jail| {
    jail.create_file("Base.toml", r#"
        cat = [1
    "#)?;

    jail.create_file("Release.toml", r#"
        cat = "
    "#)?;

    let figment = Figment::from(Toml::file("Base.toml"))
        .merge(Toml::file("Release.toml"));

    let error = figment.extract_inner::<String>("cat").unwrap_err();
    assert_eq!(error.count(), 2);

    Ok(())
});

Trait Implementations

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more
Raised when there is general error when deserializing a type. Read more
Raised when a Deserialize receives a type different from what it was expecting. Read more
Raised when a Deserialize receives a value of the right type but that is wrong for some other reason. Read more
Raised when deserializing a sequence or map and the input data contains too many or too few elements. Read more
Raised when a Deserialize enum type received a variant with an unrecognized name. Read more
Raised when a Deserialize struct type received a field with an unrecognized name. Read more
Raised when a Deserialize struct type expected to receive a required field with a particular name but that field was not present in the input. Read more
Raised when a Deserialize struct type received more than one of the same field. Read more
The lower-level source of this error, if any. Read more
👎Deprecated since 1.42.0: use the Display impl or to_string()
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type based access to context intended for error reports. Read more
Used when a Serialize implementation encounters any error while serializing a type. Read more
Converts to this type from the input type.
Converts to this type from the input type.
Converts to this type from the input type.
The type of the elements being iterated over.
Which kind of iterator are we turning this into?
Creates an iterator from a value. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Converts self into a collection.
🔬This is a nightly-only experimental API. (provide_any)
Data providers should implement this method to provide all values they are able to provide by using demand. Read more
Should always be Self
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more