eros 0.7.0

Error handling that is precise, no boilerplate, ergonomic, context aware, and performant.
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
142
143
144
145
146
147
148
149
150
151
152

use core::result::Result;

use crate::{
    ErrorUnion,
    type_set::{DebugFold, DisplayFold, TypeSet},
};

pub trait LogExt<O> {
    fn log_error(self) -> O;
    fn log_warn(self) -> O;
}

impl<T, E> LogExt<Result<T, ErrorUnion<E>>> for Result<T, ErrorUnion<E>>
where
    E: TypeSet,
    <E as TypeSet>::Variants: core::fmt::Debug + DebugFold + core::fmt::Display + DisplayFold,
{
    /// If `Err`, logs this error as "error". The logging backend is configured by feature flag, as well as
    /// if the error is logged as its display or debug version
    fn log_error(self) -> Result<T, ErrorUnion<E>> {
        self.inspect_err(|e| {
            e.log_error();
        })
    }

    /// If `Err`, logs this error as "warn". The logging backend is configured by feature flag, as well as
    /// if the error is logged as its display or debug version
    fn log_warn(self) -> Result<T, ErrorUnion<E>> {
        self.inspect_err(|e| {
            e.log_warn();
        })
    }
}

impl<T> LogExt<Result<T, ErrorUnion>> for Result<T, ErrorUnion> {
    /// If `Err`, logs this error as "error". The logging backend is configured by feature flag, as well as
    /// if the error is logged as its display or debug version
    fn log_error(self) -> Result<T, ErrorUnion> {
        self.inspect_err(|e| {
            e.log_error();
        })
    }

    /// If `Err`, logs this error as "warn". The logging backend is configured by feature flag, as well as
    /// if the error is logged as its display or debug version
    fn log_warn(self) -> Result<T, ErrorUnion> {
        self.inspect_err(|e| {
            e.log_warn();
        })
    }
}

impl<E> ErrorUnion<E>
where
    E: TypeSet,
    <E as TypeSet>::Variants: core::fmt::Debug + DebugFold + core::fmt::Display + DisplayFold,
{
    /// Logs this error as "error". The logging backend is configured by feature flag, as well as
    /// if the error is logged as its display or debug version
    #[cfg(feature = "logging")]
    pub fn log_error(&self) {
        #[cfg(all(
            feature = "log_display",
            not(feature = "log_debug"),
            feature = "tracing"
        ))]
        tracing::error!("{}", self);
        #[cfg(all(feature = "log_debug", feature = "tracing"))]
        tracing::error!("{:#?}", self);
    }

    /// Logs this error as "warn". The logging backend is configured by feature flag, as well as
    /// if the error is logged as its display or debug version
    #[cfg(feature = "logging")]
    pub fn log_warn(&self) {
        #[cfg(all(
            feature = "log_display",
            not(feature = "log_debug"),
            feature = "tracing"
        ))]
        tracing::warn!("{}", self);
        #[cfg(all(feature = "log_debug", feature = "tracing"))]
        tracing::warn!("{:#?}", self);
    }
}

impl ErrorUnion {
    /// Logs this error as "error". The logging backend is configured by feature flag, as well as
    /// if the error is logged as its display or debug version
    #[cfg(feature = "logging")]
    pub fn log_error(&self) {
        #[cfg(all(
            feature = "log_display",
            not(feature = "log_debug"),
            feature = "tracing"
        ))]
        tracing::error!("{}", self);
        #[cfg(all(feature = "log_debug", feature = "tracing"))]
        tracing::error!("{:#?}", self);
    }

    /// Logs this error as "warn". The logging backend is configured by feature flag, as well as
    /// if the error is logged as its display or debug version
    #[cfg(feature = "logging")]
    pub fn log_warn(&self) {
        #[cfg(all(
            feature = "log_display",
            not(feature = "log_debug"),
            feature = "tracing"
        ))]
        tracing::warn!("{}", self);
        #[cfg(all(feature = "log_debug", feature = "tracing"))]
        tracing::warn!("{:#?}", self);
    }
}

#[cfg(test)]
mod tests {
    use std::f32::consts::E;

    use super::*;
    use crate::any_error::AnyError;

    // Just testing it compiles
    #[test]
    #[should_panic]
    fn test_anyerror_log_error() {
        let error_union: ErrorUnion<AnyError> = todo!();
        error_union.log_error();
        let result = Err::<(), _>(error_union);
        result.log_error();
    }

    // Just testing it compiles
    #[test]
    #[should_panic]
    fn test_anyeror_log_warn() {
        let error_union: ErrorUnion<AnyError> = todo!();
        error_union.log_warn();
        let result = Err::<(), _>(error_union);
        result.log_warn();
    }

    #[test]
    fn test_normal_error_union_log_error() {
        let error_union: ErrorUnion<(std::io::Error,)> =
            ErrorUnion::new(std::io::Error::new(std::io::ErrorKind::Other, "Test error"));
        error_union.log_error();
        let result = Err::<(), _>(error_union);
        result.log_error();
    }
}