anystack 0.6.0-alpha.3

Flexible and comprehensive error handling.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128

#![cfg(feature = "std")]
#![allow(clippy::std_instead_of_core)]

use core::fmt;
use std::{error::Error, io};

use anystack::{FrameKind, Report, ResultExt as _, ResultStack};

fn io_error() -> Result<(), io::Error> {
    Err(io::Error::from(io::ErrorKind::Other))
}

#[derive(Debug)]
struct OuterError {
    inner: InnerError,
}

impl fmt::Display for OuterError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "outer error: {}", self.inner)
    }
}

impl Error for OuterError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        Some(&self.inner)
    }
}

#[derive(Debug)]
struct InnerError {
    inner: io::Error,
}

impl fmt::Display for InnerError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "inner error: {}", self.inner)
    }
}

impl Error for InnerError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        Some(&self.inner)
    }
}

fn error_with_sources() -> Result<(), OuterError> {
    Err(OuterError {
        inner: InnerError {
            inner: io::Error::from(io::ErrorKind::Other),
        },
    })
}

#[test]
fn report() {
    let report = io_error().map_err(Report::new).expect_err("not an error");
    assert!(report.contains::<io::Error>());
    assert_eq!(report.current_context().kind(), io::ErrorKind::Other);
}

#[test]
fn error() {
    let report = error_with_sources()
        .map_err(Report::new)
        .expect_err("not an error");

    let mut frames = report
        .frames()
        .skip_while(|frame| !matches!(frame.kind(), FrameKind::Context(_)));
    assert!(frames.next().expect("no frames").is::<OuterError>());

    // "inner error: other error"
    let mut frames = frames.skip_while(|frame| !matches!(frame.kind(), FrameKind::Context(_)));
    assert!(frames.next().is_some());

    // "other error"
    let mut frames = frames.skip_while(|frame| !matches!(frame.kind(), FrameKind::Context(_)));
    assert!(frames.next().is_some());

    // no further sources
    let mut frames = frames.skip_while(|frame| !matches!(frame.kind(), FrameKind::Context(_)));
    assert!(frames.next().is_none());
}

#[test]
fn into_report() {
    let report = io_error()
        .map_err(Report::<io::Error>::from)
        .expect_err("not an error");
    assert!(report.contains::<io::Error>());
    assert_eq!(report.current_context().kind(), io::ErrorKind::Other);
}

fn returning_boxed_error() -> Result<(), Box<dyn core::error::Error + Send + Sync>> {
    io_error().attach(10_u32)?;
    Ok(())
}

#[test]
fn boxed_error() {
    let report = returning_boxed_error().expect_err("not an error");
    assert_eq!(
        report.to_string(),
        io_error().expect_err("not an error").to_string()
    );
}

#[test]
fn dyn_error_auto_propagation() {
    fn base_err() -> ResultStack<()> {
        #[expect(clippy::try_err)]
        Err(io::Error::from(io::ErrorKind::Other))?;
        Ok(())
    }

    fn other_report() -> ResultStack<()> {
        #[expect(clippy::try_err)]
        Err(Report::new(io::Error::from(io::ErrorKind::Other)))?;
        Ok(())
    }

    let _: ResultStack<()> = base_err();
    let _: Report<dyn Error> = io::Error::from(io::ErrorKind::Other).into();

    let _: ResultStack<()> = other_report();
    let _: Report<dyn Error> = Report::new(io::Error::from(io::ErrorKind::Other)).into();
}