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No need for thiserror as well as anyhow.

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This commit is contained in:
Andrew Walbran 2023-01-16 17:41:17 +00:00
parent 9fa0e89e90
commit e5c97e12cb
1 changed files with 4 additions and 10 deletions
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14
src/error-handling/error-contexts.md
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@ -7,14 +7,7 @@ custom error types:
```rust,editable,compile_fail ```rust,editable,compile_fail
use std::{fs, io}; use std::{fs, io};
use std::io::Read; use std::io::Read;
use thiserror::Error; use anyhow::{Context, Result, bail};
use anyhow::{Context, Result};
#[derive(Error, Debug)]
enum ReadUsernameError {
#[error("Found no username in {0}")]
EmptyUsername(String),
}
fn read_username(path: &str) -> Result<String> { fn read_username(path: &str) -> Result<String> {
let mut username = String::with_capacity(100); let mut username = String::with_capacity(100);
@ -23,7 +16,7 @@ fn read_username(path: &str) -> Result<String> {
.read_to_string(&mut username) .read_to_string(&mut username)
.context("Failed to read")?; .context("Failed to read")?;
if username.is_empty() { if username.is_empty() {
return Err(ReadUsernameError::EmptyUsername(String::from(path)).into()); bail!("Found no username in {path}");
} }
Ok(username) Ok(username)
} }
@ -39,7 +32,8 @@ fn main() {
<details> <details>
* `anyhow::Result<T>` is generic and it can hold any `Error` implementation without changing the type signature. * `anyhow::Result<V>` is a type alias for `Result<V, anyhow::Error>`.
* `anyhow::Error` is generic and it can hold any `Error` implementation without changing the type signature.
* Actual error type inside of it can be extracted for examination if necessary. * Actual error type inside of it can be extracted for examination if necessary.
* Functionality provided by `anyhow::Result<T>` may be familiar to Go developers, as it provides similar usage patterns and ergonomics * Functionality provided by `anyhow::Result<T>` may be familiar to Go developers, as it provides similar usage patterns and ergonomics
of `(T, error)` from Go. of `(T, error)` from Go.