xref: /aosp_15_r20/external/rust/android-crates-io/crates/miette/src/lib.rs

#![deny(missing_docs, missing_debug_implementations, nonstandard_style)]
#![warn(unreachable_pub, rust_2018_idioms)]
//! You run miette? You run her code like the software? Oh. Oh! Error code for
//! coder! Error code for One Thousand Lines!
//!
//! ## About
//!
//! `miette` is a diagnostic library for Rust. It includes a series of
//! traits/protocols that allow you to hook into its error reporting facilities,
//! and even write your own error reports! It lets you define error types that
//! can print out like this (or in any format you like!):
//!
//! <img src="https://raw.githubusercontent.com/zkat/miette/main/images/serde_json.png" alt="Hi! miette also includes a screen-reader-oriented diagnostic printer that's enabled in various situations, such as when you use NO_COLOR or CLICOLOR settings, or on CI. This behavior is also fully configurable and customizable. For example, this is what this particular diagnostic will look like when the narrated printer is enabled:
//! \
//! Error: Received some bad JSON from the source. Unable to parse.
//!     Caused by: missing field `foo` at line 1 column 1700
//! \
//! Begin snippet for https://api.nuget.org/v3/registration5-gz-semver2/json.net/index.json starting
//! at line 1, column 1659
//! \
//! snippet line 1: gs&quot;:[&quot;json&quot;],&quot;title&quot;:&quot;&quot;,&quot;version&quot;:&quot;1.0.0&quot;},&quot;packageContent&quot;:&quot;https://api.nuget.o
//!     highlight starting at line 1, column 1699: last parsing location
//! \
//! diagnostic help: This is a bug. It might be in ruget, or it might be in the
//! source you're using, but it's definitely a bug and should be reported.
//! diagnostic error code: ruget::api::bad_json
//! " />
//!
//! > **NOTE: You must enable the `"fancy"` crate feature to get fancy report
//! output like in the screenshots above.** You should only do this in your
//! toplevel crate, as the fancy feature pulls in a number of dependencies that
//! libraries and such might not want.
//!
//! ## Table of Contents <!-- omit in toc -->
//!
//! - [About](#about)
//! - [Features](#features)
//! - [Installing](#installing)
//! - [Example](#example)
//! - [Using](#using)
//!   - [... in libraries](#-in-libraries)
//!   - [... in application code](#-in-application-code)
//!   - [... in `main()`](#-in-main)
//!   - [... diagnostic code URLs](#-diagnostic-code-urls)
//!   - [... snippets](#-snippets)
//!   - [... multiple related errors](#-multiple-related-errors)
//!   - [... delayed source code](#-delayed-source-code)
//!   - [... handler options](#-handler-options)
//!   - [... dynamic diagnostics](#-dynamic-diagnostics)
//! - [Acknowledgements](#acknowledgements)
//! - [License](#license)
//!
//! ## Features
//!
//! - Generic [`Diagnostic`] protocol, compatible (and dependent on)
//!   [`std::error::Error`].
//! - Unique error codes on every [`Diagnostic`].
//! - Custom links to get more details on error codes.
//! - Super handy derive macro for defining diagnostic metadata.
//! - Replacements for [`anyhow`](https://docs.rs/anyhow)/[`eyre`](https://docs.rs/eyre)
//!   types [`Result`], [`Report`] and the [`miette!`] macro for the
//!   `anyhow!`/`eyre!` macros.
//! - Generic support for arbitrary [`SourceCode`]s for snippet data, with
//!   default support for `String`s included.
//!
//! The `miette` crate also comes bundled with a default [`ReportHandler`] with
//! the following features:
//!
//! - Fancy graphical [diagnostic output](#about), using ANSI/Unicode text
//! - single- and multi-line highlighting support
//! - Screen reader/braille support, gated on [`NO_COLOR`](http://no-color.org/),
//!   and other heuristics.
//! - Fully customizable graphical theming (or overriding the printers
//!   entirely).
//! - Cause chain printing
//! - Turns diagnostic codes into links in [supported terminals](https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda).
//!
//! ## Installing
//!
//! ```sh
//! $ cargo add miette
//! ```
//!
//! If you want to use the fancy printer in all these screenshots:
//!
//! ```sh
//! $ cargo add miette --features fancy
//! ```
//!
//! ## Example
//!
//! ```rust
//! /*
//! You can derive a `Diagnostic` from any `std::error::Error` type.
//!
//! `thiserror` is a great way to define them, and plays nicely with `miette`!
//! */
//! use miette::{Diagnostic, SourceSpan};
//! use thiserror::Error;
//!
//! #[derive(Error, Debug, Diagnostic)]
//! #[error("oops!")]
//! #[diagnostic(
//!     code(oops::my::bad),
//!     url(docsrs),
//!     help("try doing it better next time?")
//! )]
//! struct MyBad {
//!     // The Source that we're gonna be printing snippets out of.
//!     // This can be a String if you don't have or care about file names.
//!     #[source_code]
//!     src: NamedSource,
//!     // Snippets and highlights can be included in the diagnostic!
//!     #[label("This bit here")]
//!     bad_bit: SourceSpan,
//! }
//!
//! /*
//! Now let's define a function!
//!
//! Use this `Result` type (or its expanded version) as the return type
//! throughout your app (but NOT your libraries! Those should always return
//! concrete types!).
//! */
//! use miette::{NamedSource, Result};
//! fn this_fails() -> Result<()> {
//!     // You can use plain strings as a `Source`, or anything that implements
//!     // the one-method `Source` trait.
//!     let src = "source\n  text\n    here".to_string();
//!     let len = src.len();
//!
//!     Err(MyBad {
//!         src: NamedSource::new("bad_file.rs", src),
//!         bad_bit: (9, 4).into(),
//!     })?;
//!
//!     Ok(())
//! }
//!
//! /*
//! Now to get everything printed nicely, just return a `Result<()>`
//! and you're all set!
//!
//! Note: You can swap out the default reporter for a custom one using
//! `miette::set_hook()`
//! */
//! fn pretend_this_is_main() -> Result<()> {
//!     // kaboom~
//!     this_fails()?;
//!
//!     Ok(())
//! }
//! ```
//!
//! And this is the output you'll get if you run this program:
//!
//! <img src="https://raw.githubusercontent.com/zkat/miette/main/images/single-line-example.png" alt="
//! Narratable printout:
//! \
//! Error: Types mismatched for operation.
//!     Diagnostic severity: error
//! Begin snippet starting at line 1, column 1
//! \
//! snippet line 1: 3 + &quot;5&quot;
//!     label starting at line 1, column 1: int
//!     label starting at line 1, column 1: doesn't support these values.
//!     label starting at line 1, column 1: string
//! diagnostic help: Change int or string to be the right types and try again.
//! diagnostic code: nu::parser::unsupported_operation
//! For more details, see https://docs.rs/nu-parser/0.1.0/nu-parser/enum.ParseError.html#variant.UnsupportedOperation">
//!
//! ## Using
//!
//! ### ... in libraries
//!
//! `miette` is _fully compatible_ with library usage. Consumers who don't know
//! about, or don't want, `miette` features can safely use its error types as
//! regular [`std::error::Error`].
//!
//! We highly recommend using something like [`thiserror`](https://docs.rs/thiserror)
//! to define unique error types and error wrappers for your library.
//!
//! While `miette` integrates smoothly with `thiserror`, it is _not required_.
//! If you don't want to use the [`Diagnostic`] derive macro, you can implement
//! the trait directly, just like with `std::error::Error`.
//!
//! ```rust
//! // lib/error.rs
//! use miette::{Diagnostic, SourceSpan};
//! use thiserror::Error;
//!
//! #[derive(Error, Diagnostic, Debug)]
//! pub enum MyLibError {
//!     #[error(transparent)]
//!     #[diagnostic(code(my_lib::io_error))]
//!     IoError(#[from] std::io::Error),
//!
//!     #[error("Oops it blew up")]
//!     #[diagnostic(code(my_lib::bad_code))]
//!     BadThingHappened,
//!
//!     #[error(transparent)]
//!     // Use `#[diagnostic(transparent)]` to wrap another [`Diagnostic`]. You won't see labels otherwise
//!     #[diagnostic(transparent)]
//!     AnotherError(#[from] AnotherError),
//! }
//!
//! #[derive(Error, Diagnostic, Debug)]
//! #[error("another error")]
//! pub struct AnotherError {
//!    #[label("here")]
//!    pub at: SourceSpan
//! }
//! ```
//!
//! Then, return this error type from all your fallible public APIs. It's a best
//! practice to wrap any "external" error types in your error `enum` instead of
//! using something like [`Report`] in a library.
//!
//! ### ... in application code
//!
//! Application code tends to work a little differently than libraries. You
//! don't always need or care to define dedicated error wrappers for errors
//! coming from external libraries and tools.
//!
//! For this situation, `miette` includes two tools: [`Report`] and
//! [`IntoDiagnostic`]. They work in tandem to make it easy to convert regular
//! `std::error::Error`s into [`Diagnostic`]s. Additionally, there's a
//! [`Result`] type alias that you can use to be more terse.
//!
//! When dealing with non-`Diagnostic` types, you'll want to
//! `.into_diagnostic()` them:
//!
//! ```rust
//! // my_app/lib/my_internal_file.rs
//! use miette::{IntoDiagnostic, Result};
//! use semver::Version;
//!
//! pub fn some_tool() -> Result<Version> {
//!     Ok("1.2.x".parse().into_diagnostic()?)
//! }
//! ```
//!
//! `miette` also includes an `anyhow`/`eyre`-style `Context`/`WrapErr` traits
//! that you can import to add ad-hoc context messages to your `Diagnostic`s, as
//! well, though you'll still need to use `.into_diagnostic()` to make use of
//! it:
//!
//! ```rust
//! // my_app/lib/my_internal_file.rs
//! use miette::{IntoDiagnostic, Result, WrapErr};
//! use semver::Version;
//!
//! pub fn some_tool() -> Result<Version> {
//!     Ok("1.2.x"
//!         .parse()
//!         .into_diagnostic()
//!         .wrap_err("Parsing this tool's semver version failed.")?)
//! }
//! ```
//!
//! To construct your own simple adhoc error use the [miette!] macro:
//! ```rust
//! // my_app/lib/my_internal_file.rs
//! use miette::{miette, IntoDiagnostic, Result, WrapErr};
//! use semver::Version;
//!
//! pub fn some_tool() -> Result<Version> {
//!     let version = "1.2.x";
//!     Ok(version
//!         .parse()
//!         .map_err(|_| miette!("Invalid version {}", version))?)
//! }
//! ```
//! There are also similar [bail!] and [ensure!] macros.
//!
//! ### ... in `main()`
//!
//! `main()` is just like any other part of your application-internal code. Use
//! `Result` as your return value, and it will pretty-print your diagnostics
//! automatically.
//!
//! > **NOTE:** You must enable the `"fancy"` crate feature to get fancy report
//! output like in the screenshots here.** You should only do this in your
//! toplevel crate, as the fancy feature pulls in a number of dependencies that
//! libraries and such might not want.
//!
//! ```rust
//! use miette::{IntoDiagnostic, Result};
//! use semver::Version;
//!
//! fn pretend_this_is_main() -> Result<()> {
//!     let version: Version = "1.2.x".parse().into_diagnostic()?;
//!     println!("{}", version);
//!     Ok(())
//! }
//! ```
//!
//! Please note: in order to get fancy diagnostic rendering with all the pretty
//! colors and arrows, you should install `miette` with the `fancy` feature
//! enabled:
//!
//! ```toml
//! miette = { version = "X.Y.Z", features = ["fancy"] }
//! ```
//!
//! ### ... diagnostic code URLs
//!
//! `miette` supports providing a URL for individual diagnostics. This URL will
//! be displayed as an actual link in supported terminals, like so:
//!
//! <img
//! src="https://raw.githubusercontent.com/zkat/miette/main/images/code_linking.png"
//! alt=" Example showing the graphical report printer for miette
//! pretty-printing an error code. The code is underlined and followed by text
//! saying to 'click here'. A hover tooltip shows a full-fledged URL that can be
//! Ctrl+Clicked to open in a browser.
//! \
//! This feature is also available in the narratable printer. It will add a line
//! after printing the error code showing a plain URL that you can visit.
//! ">
//!
//! To use this, you can add a `url()` sub-param to your `#[diagnostic]`
//! attribute:
//!
//! ```rust
//! use miette::Diagnostic;
//! use thiserror::Error;
//!
//! #[derive(Error, Diagnostic, Debug)]
//! #[error("kaboom")]
//! #[diagnostic(
//!     code(my_app::my_error),
//!     // You can do formatting!
//!     url("https://my_website.com/error_codes#{}", self.code().unwrap())
//! )]
//! struct MyErr;
//! ```
//!
//! Additionally, if you're developing a library and your error type is exported
//! from your crate's top level, you can use a special `url(docsrs)` option
//! instead of manually constructing the URL. This will automatically create a
//! link to this diagnostic on `docs.rs`, so folks can just go straight to your
//! (very high quality and detailed!) documentation on this diagnostic:
//!
//! ```rust
//! use miette::Diagnostic;
//! use thiserror::Error;
//!
//! #[derive(Error, Diagnostic, Debug)]
//! #[diagnostic(
//!     code(my_app::my_error),
//!     // Will link users to https://docs.rs/my_crate/0.0.0/my_crate/struct.MyErr.html
//!     url(docsrs)
//! )]
//! #[error("kaboom")]
//! struct MyErr;
//! ```
//!
//! ### ... snippets
//!
//! Along with its general error handling and reporting features, `miette` also
//! includes facilities for adding error spans/annotations/labels to your
//! output. This can be very useful when an error is syntax-related, but you can
//! even use it to print out sections of your own source code!
//!
//! To achieve this, `miette` defines its own lightweight [`SourceSpan`] type.
//! This is a basic byte-offset and length into an associated [`SourceCode`]
//! and, along with the latter, gives `miette` all the information it needs to
//! pretty-print some snippets! You can also use your own `Into<SourceSpan>`
//! types as label spans.
//!
//! The easiest way to define errors like this is to use the
//! `derive(Diagnostic)` macro:
//!
//! ```rust
//! use miette::{Diagnostic, SourceSpan};
//! use thiserror::Error;
//!
//! #[derive(Diagnostic, Debug, Error)]
//! #[error("oops")]
//! #[diagnostic(code(my_lib::random_error))]
//! pub struct MyErrorType {
//!     // The `Source` that miette will use.
//!     #[source_code]
//!     src: String,
//!
//!     // This will underline/mark the specific code inside the larger
//!     // snippet context.
//!     #[label = "This is the highlight"]
//!     err_span: SourceSpan,
//!
//!     // You can add as many labels as you want.
//!     // They'll be rendered sequentially.
//!     #[label("This is bad")]
//!     snip2: (usize, usize), // `(usize, usize)` is `Into<SourceSpan>`!
//!
//!     // Snippets can be optional, by using Option:
//!     #[label("some text")]
//!     snip3: Option<SourceSpan>,
//!
//!     // with or without label text
//!     #[label]
//!     snip4: Option<SourceSpan>,
//! }
//! ```
//!
//! #### ... help text
//! `miette` provides two facilities for supplying help text for your errors:
//!
//! The first is the `#[help()]` format attribute that applies to structs or
//! enum variants:
//!
//! ```rust
//! use miette::Diagnostic;
//! use thiserror::Error;
//!
//! #[derive(Debug, Diagnostic, Error)]
//! #[error("welp")]
//! #[diagnostic(help("try doing this instead"))]
//! struct Foo;
//! ```
//!
//! The other is by programmatically supplying the help text as a field to
//! your diagnostic:
//!
//! ```rust
//! use miette::Diagnostic;
//! use thiserror::Error;
//!
//! #[derive(Debug, Diagnostic, Error)]
//! #[error("welp")]
//! #[diagnostic()]
//! struct Foo {
//!     #[help]
//!     advice: Option<String>, // Can also just be `String`
//! }
//!
//! let err = Foo {
//!     advice: Some("try doing this instead".to_string()),
//! };
//! ```
//!
//! ### ... multiple related errors
//!
//! `miette` supports collecting multiple errors into a single diagnostic, and
//! printing them all together nicely.
//!
//! To do so, use the `#[related]` tag on any `IntoIter` field in your
//! `Diagnostic` type:
//!
//! ```rust
//! use miette::Diagnostic;
//! use thiserror::Error;
//!
//! #[derive(Debug, Error, Diagnostic)]
//! #[error("oops")]
//! struct MyError {
//!     #[related]
//!     others: Vec<MyError>,
//! }
//! ```
//!
//! ### ... delayed source code
//!
//! Sometimes it makes sense to add source code to the error message later.
//! One option is to use [`with_source_code()`](Report::with_source_code)
//! method for that:
//!
//! ```rust,no_run
//! use miette::{Diagnostic, SourceSpan};
//! use thiserror::Error;
//!
//! #[derive(Diagnostic, Debug, Error)]
//! #[error("oops")]
//! #[diagnostic()]
//! pub struct MyErrorType {
//!     // Note: label but no source code
//!     #[label]
//!     err_span: SourceSpan,
//! }
//!
//! fn do_something() -> miette::Result<()> {
//!     // This function emits actual error with label
//!     return Err(MyErrorType {
//!         err_span: (7..11).into(),
//!     })?;
//! }
//!
//! fn main() -> miette::Result<()> {
//!     do_something().map_err(|error| {
//!         // And this code provides the source code for inner error
//!         error.with_source_code(String::from("source code"))
//!     })
//! }
//! ```
//!
//! Also source code can be provided by a wrapper type. This is especially
//! useful in combination with `related`, when multiple errors should be
//! emitted at the same time:
//!
//! ```rust,no_run
//! use miette::{Diagnostic, Report, SourceSpan};
//! use thiserror::Error;
//!
//! #[derive(Diagnostic, Debug, Error)]
//! #[error("oops")]
//! #[diagnostic()]
//! pub struct InnerError {
//!     // Note: label but no source code
//!     #[label]
//!     err_span: SourceSpan,
//! }
//!
//! #[derive(Diagnostic, Debug, Error)]
//! #[error("oops: multiple errors")]
//! #[diagnostic()]
//! pub struct MultiError {
//!     // Note source code by no labels
//!     #[source_code]
//!     source_code: String,
//!     // The source code above is used for these errors
//!     #[related]
//!     related: Vec<InnerError>,
//! }
//!
//! fn do_something() -> Result<(), Vec<InnerError>> {
//!     Err(vec![
//!         InnerError {
//!             err_span: (0..6).into(),
//!         },
//!         InnerError {
//!             err_span: (7..11).into(),
//!         },
//!     ])
//! }
//!
//! fn main() -> miette::Result<()> {
//!     do_something().map_err(|err_list| MultiError {
//!         source_code: "source code".into(),
//!         related: err_list,
//!     })?;
//!     Ok(())
//! }
//! ```
//!
//! ### ... Diagnostic-based error sources.
//!
//! When one uses the `#[source]` attribute on a field, that usually comes
//! from `thiserror`, and implements a method for
//! [`std::error::Error::source`]. This works in many cases, but it's lossy:
//! if the source of the diagnostic is a diagnostic itself, the source will
//! simply be treated as an `std::error::Error`.
//!
//! While this has no effect on the existing _reporters_, since they don't use
//! that information right now, APIs who might want this information will have
//! no access to it.
//!
//! If it's important for you for this information to be available to users,
//! you can use `#[diagnostic_source]` alongside `#[source]`. Not that you
//! will likely want to use _both_:
//!
//! ```rust
//! use miette::Diagnostic;
//! use thiserror::Error;
//!
//! #[derive(Debug, Diagnostic, Error)]
//! #[error("MyError")]
//! struct MyError {
//!     #[source]
//!     #[diagnostic_source]
//!     the_cause: OtherError,
//! }
//!
//! #[derive(Debug, Diagnostic, Error)]
//! #[error("OtherError")]
//! struct OtherError;
//! ```
//!
//! ### ... handler options
//!
//! [`MietteHandler`] is the default handler, and is very customizable. In
//! most cases, you can simply use [`MietteHandlerOpts`] to tweak its behavior
//! instead of falling back to your own custom handler.
//!
//! Usage is like so:
//!
//! ```rust,ignore
//! miette::set_hook(Box::new(|_| {
//!     Box::new(
//!         miette::MietteHandlerOpts::new()
//!             .terminal_links(true)
//!             .unicode(false)
//!             .context_lines(3)
//!             .tab_width(4)
//!             .build(),
//!     )
//! }))
//!
//! # .unwrap()
//! ```
//!
//! See the docs for [`MietteHandlerOpts`] for more details on what you can
//! customize!
//!
//! ### ... dynamic diagnostics
//!
//! If you...
//! - ...don't know all the possible errors upfront
//! - ...need to serialize/deserialize errors
//! then you may want to use [`miette!`], [`diagnostic!`] macros or
//! [`MietteDiagnostic`] directly to create diagnostic on the fly.
//!
//! ```rust,ignore
//! # use miette::{miette, LabeledSpan, Report};
//!
//! let source = "2 + 2 * 2 = 8".to_string();
//! let report = miette!(
//!   labels = vec[
//!       LabeledSpan::at(12..13, "this should be 6"),
//!   ],
//!   help = "'*' has greater precedence than '+'",
//!   "Wrong answer"
//! ).with_source_code(source);
//! println!("{:?}", report)
//! ```
//!
//! ## Acknowledgements
//!
//! `miette` was not developed in a void. It owes enormous credit to various
//! other projects and their authors:
//!
//! - [`anyhow`](http://crates.io/crates/anyhow) and [`color-eyre`](https://crates.io/crates/color-eyre):
//!   these two enormously influential error handling libraries have pushed
//!   forward the experience of application-level error handling and error
//!   reporting. `miette`'s `Report` type is an attempt at a very very rough
//!   version of their `Report` types.
//! - [`thiserror`](https://crates.io/crates/thiserror) for setting the standard
//!   for library-level error definitions, and for being the inspiration behind
//!   `miette`'s derive macro.
//! - `rustc` and [@estebank](https://github.com/estebank) for their
//!   state-of-the-art work in compiler diagnostics.
//! - [`ariadne`](https://crates.io/crates/ariadne) for pushing forward how
//!   _pretty_ these diagnostics can really look!
//!
//! ## License
//!
//! `miette` is released to the Rust community under the [Apache license
//! 2.0](./LICENSE).
//!
//! It also includes code taken from [`eyre`](https://github.com/yaahc/eyre),
//! and some from [`thiserror`](https://github.com/dtolnay/thiserror), also
//! under the Apache License. Some code is taken from
//! [`ariadne`](https://github.com/zesterer/ariadne), which is MIT licensed.
pub use miette_derive::*;

pub use error::*;
pub use eyreish::*;
#[cfg(feature = "fancy-no-backtrace")]
pub use handler::*;
pub use handlers::*;
pub use miette_diagnostic::*;
pub use named_source::*;
#[cfg(feature = "fancy")]
pub use panic::*;
pub use protocol::*;

mod chain;
mod diagnostic_chain;
mod error;
mod eyreish;
#[cfg(feature = "fancy-no-backtrace")]
mod handler;
mod handlers;
#[doc(hidden)]
pub mod macro_helpers;
mod miette_diagnostic;
mod named_source;
#[cfg(feature = "fancy")]
mod panic;
mod protocol;
mod source_impls;