thiserror-ext 0.3.0

Useful extension utilities for `thiserror`.
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
137
138
139
140
141

#![cfg_attr(feature = "backtrace", feature(error_generic_member_access))]

pub mod inner {
    use thiserror::Error;
    use thiserror_ext_derive::{Box, Macro};

    #[derive(Error, Debug, Macro, Box)]
    #[thiserror_ext(newtype(name = BoxMyError))]
    pub(super) enum MyError {
        #[error("foo {message}")]
        Foo { message: String },

        #[error("bar {message}")]
        Bar { issue: Option<i32>, message: String },

        #[error("baz {msg}")]
        Baz {
            issue: Option<i32>,
            pr: Option<i32>,
            #[message]
            msg: String,
        },

        #[error("qux {msg}")]
        Qux {
            extra: String,
            #[message]
            msg: Box<str>,
        },

        #[error("quux {message}")]
        Quux { message: String },
    }
    #[derive(Error, Debug, Macro)]
    #[error("not implemented: {message}, issue: {issue:?}")]
    #[thiserror_ext(macro(mangle, path = "crate::inner", vis = pub(super)))]
    pub struct NotImplemented {
        pub issue: Option<i32>,
        pub message: String,
    }
}

mod tests {
    use crate::inner::{BoxMyError, MyError, NotImplemented};

    #[test]
    fn test() {
        use crate::inner::{bar, baz, foo, qux};

        let _: BoxMyError = foo!("hello {}", 42);

        let _ = bar!("hello {}", 42);
        let _ = bar!(issue = 42, "hello {}", 42);
        let _ = bar!(issue = None, "hello {}", 42);
        let a = bar!(issue = Some(42), "hello {}", 42);
        assert!(
            matches!(a.inner(), MyError::Bar { issue: Some(42), message } if message == "hello 42")
        );

        let _ = baz!("hello {}", 42);
        let _ = baz!(issue = 42, pr = Some(88), "hello {}", 42);
        let _ = baz!(issue = None, pr = 88, "hello {}", 42);
        let _ = baz!(issue = 42, "hello {}", 42);
        let a = baz!(pr = 88, "hello {}", 42);
        let _ = baz!(pr = Some(88), "hello {}", 42);
        assert!(matches!(
            a.inner(),
            MyError::Baz {
                pr: Some(88),
                issue: None,
                ..
            }
        ));

        let _ = qux!(extra = "233", "hello {}", 42);
        let _ = qux!(extra = "233".to_owned(), "hello {}", 42);
        let a = qux!("hello {}", 42); // use default `extra`
        assert!(matches!(
            a.inner(),
            MyError::Qux {
                extra,
                msg,
                ..
            } if extra == "" && msg.as_ref() == "hello 42"
        ));
    }

    #[test]
    fn test_bail() {
        use crate::inner::bail_quux;

        fn test() -> Result<(), anyhow::Error> {
            match 1 + 1 {
                3 => Ok(()),
                _ => bail_quux!("1 + 1 != 3"),
            }
        }

        let error = test().unwrap_err();
        assert!(matches!(
            error.downcast_ref::<BoxMyError>().unwrap().inner(),
            MyError::Quux { message } if message == "1 + 1 != 3"
        ));
    }

    #[test]
    fn test_struct() {
        use crate::inner::bail_not_implemented;
        use crate::inner::not_implemented;

        // As we're mangling the macro name, we can't use the macro directly.
        //
        // use crate::__thiserror_ext_macro__not_implemented__not_implemented;
        // use crate::not_implemented;

        let a: NotImplemented = not_implemented!(issue = 42, "hello {}", 42);
        assert!(matches!(
            a,
            NotImplemented {
                issue: Some(42),
                message,
            } if message == "hello 42"
        ));

        fn test() -> Result<(), anyhow::Error> {
            match 1 + 1 {
                3 => Ok(()),
                _ => bail_not_implemented!(issue = 42, "1 + 1 != 3"),
            }
        }

        let error = test().unwrap_err();
        assert!(matches!(
            error.downcast_ref::<NotImplemented>().unwrap(),
            NotImplemented {
                issue: Some(42),
                message,
            } if message == "1 + 1 != 3"
        ));
    }
}