cargo_metadata/errors.rs
1use std::{io, str::Utf8Error, string::FromUtf8Error};
2
3/// Custom result type for `cargo_metadata::Error`
4pub type Result<T> = ::std::result::Result<T, Error>;
5
6/// Error returned when executing/parsing `cargo metadata` fails.
7///
8/// # Note about Backtraces
9///
10/// This error type does not contain backtraces, but each error variant
11/// comes from _one_ specific place, so it's not really needed for the
12/// inside of this crate. If you need a backtrace down to, but not inside
13/// of, a failed call of `cargo_metadata` you can do one of multiple thinks:
14///
15/// 1. Convert it to a `failure::Error` (possible using the `?` operator),
16/// which is similar to a `Box<::std::error::Error + 'static + Send + Sync>`.
17/// 2. Have appropriate variants in your own error type. E.g. you could wrap
18/// a `failure::Context<Error>` or add a `failure::Backtrace` field (which
19/// is empty if `RUST_BACKTRACE` is not set, so it's simple to use).
20/// 3. You still can place a failure based error into a `error_chain` if you
21/// really want to. (Either through foreign_links or by making it a field
22/// value of a `ErrorKind` variant).
23///
24#[derive(Debug, thiserror::Error)]
25pub enum Error {
26 /// Error during execution of `cargo metadata`
27 #[error("`cargo metadata` exited with an error: {stderr}")]
28 CargoMetadata {
29 /// stderr returned by the `cargo metadata` command
30 stderr: String,
31 },
32
33 /// IO Error during execution of `cargo metadata`
34 #[error("failed to start `cargo metadata`: {0}")]
35 Io(#[from] io::Error),
36
37 /// Output of `cargo metadata` was not valid utf8
38 #[error("cannot convert the stdout of `cargo metadata`: {0}")]
39 Utf8(#[from] Utf8Error),
40
41 /// Error output of `cargo metadata` was not valid utf8
42 #[error("cannot convert the stderr of `cargo metadata`: {0}")]
43 ErrUtf8(#[from] FromUtf8Error),
44
45 /// Deserialization error (structure of json did not match expected structure)
46 #[error("failed to interpret `cargo metadata`'s json: {0}")]
47 Json(#[from] ::serde_json::Error),
48
49 /// The output did not contain any json
50 #[error("could not find any json in the output of `cargo metadata`")]
51 NoJson,
52}