error-stack 0.8.0

A context-aware error-handling library that supports arbitrary attached user data
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
129
130
131
132
133
134
135
136

#![cfg_attr(nightly, feature(error_generic_member_access))]

mod common;

use core::{any::TypeId, iter::zip, ops::ControlFlow, panic::Location};

use common::*;

#[test]
fn opaque_attachment() {
    let mut report = create_report()
        .attach_opaque(AttachmentA(10))
        .attach_opaque(AttachmentB(20));

    let flow = report.frames_mut(|frame| {
        let source = frame
            .sources_mut()
            .first_mut()
            .expect("No source frame found");
        let attachment = source
            .downcast_mut::<AttachmentA>()
            .expect("Wrong source frame");
        attachment.0 += 10;
        ControlFlow::Break(())
    });
    assert!(flow.is_break(), "No frame found");

    let frame = report.frames().next().expect("No frame found");
    assert_eq!(frame.sources().len(), 1);
    let source = frame.sources().first().expect("No source frame found");
    let attachment = source
        .downcast_ref::<AttachmentA>()
        .expect("Wrong source frame");
    assert_eq!(attachment.0, 20);
}

#[test]
fn sources() {
    let mut report_a = create_report().attach_opaque(AttachmentA(10)).expand();
    let report_b = create_report().attach_opaque(AttachmentA(20));
    report_a.push(report_b);
    let mut report = report_a.attach_opaque(AttachmentB(30));

    let flow = report.frames_mut(|frame| {
        assert_eq!(frame.sources().len(), 2);

        for source in frame.sources_mut() {
            let attachment = source
                .downcast_mut::<AttachmentA>()
                .expect("Wrong source frame");
            attachment.0 += 5;
        }
        ControlFlow::Break(())
    });
    assert!(flow.is_break(), "No frames");

    let frame = report.frames().next().expect("No frames");
    for (source, expect) in zip(frame.sources(), [15, 25]) {
        let attachment = source
            .downcast_ref::<AttachmentA>()
            .expect("Wrong source frame");
        assert_eq!(attachment.0, expect);
    }
}

#[test]
fn printable_attachment() {
    let mut report = create_report()
        .attach(PrintableA(10))
        .attach(PrintableB(20));

    let flow = report.frames_mut(|frame| {
        let source = frame
            .sources_mut()
            .first_mut()
            .expect("No source frame found");
        let attachment = source
            .downcast_mut::<PrintableA>()
            .expect("Wrong source frame");
        attachment.0 += 10;
        ControlFlow::Break(())
    });
    assert!(flow.is_break(), "No frame found");

    let frame = report.frames().next().expect("No frame found");
    assert_eq!(frame.sources().len(), 1);
    let source = frame.sources().first().expect("No source frame found");
    let attachment = source
        .downcast_ref::<PrintableA>()
        .expect("Wrong source frame");
    assert_eq!(attachment.0, 20);
}

#[test]
fn context() {
    let mut report = create_report().change_context(ContextA(10));

    let flow = report.frames_mut(|frame| {
        assert_eq!(frame.sources().len(), 1);
        assert!(frame.is::<Location>(), "not a location frame");

        let source = frame
            .sources_mut()
            .first_mut()
            .expect("no source frame found");

        let context = source
            .downcast_mut::<ContextA>()
            .expect("not a context frame");
        context.0 += 10;
        ControlFlow::Break(())
    });
    assert!(flow.is_break(), "No location frame found");

    let frame = report.frames().next().expect("No location frame found");
    assert_eq!(frame.sources().len(), 1);
    let source = frame.sources().first().expect("no source frame found");
    let context = source
        .downcast_ref::<ContextA>()
        .expect("not a context frame");
    assert_eq!(context.0, 20);
}

#[test]
fn type_id() {
    let report = create_report().attach_opaque(2_u32);
    let current = report.current_frame();

    assert_eq!(current.type_id(), TypeId::of::<u32>());

    let context = report
        .frames()
        .last()
        .expect("should have at least a single frame");
    assert_eq!(context.type_id(), TypeId::of::<RootError>());
}