reliakit_collections/
error.rs

1use core::fmt;
2
3/// Error returned by bounded collection operations.
4#[non_exhaustive]
5#[derive(Debug, Clone, PartialEq, Eq)]
6pub enum CollectionError {
7    /// The collection has fewer elements than the required minimum.
8    TooFew {
9        /// The required minimum number of elements.
10        min: usize,
11        /// The actual number of elements.
12        actual: usize,
13    },
14    /// The collection has more elements than the allowed maximum.
15    TooMany {
16        /// The allowed maximum number of elements.
17        max: usize,
18        /// The actual number of elements.
19        actual: usize,
20    },
21    /// The const generic bounds are invalid (`MIN > MAX`).
22    InvalidBounds {
23        /// The configured minimum bound.
24        min: usize,
25        /// The configured maximum bound.
26        max: usize,
27    },
28    /// A capacity of zero was requested where a positive capacity is required.
29    ZeroCapacity,
30    /// A duplicate key or element was supplied where uniqueness is required.
31    Duplicate,
32}
33
34/// Result alias for bounded collection operations.
35pub type CollectionResult<T = ()> = Result<T, CollectionError>;
36
37impl fmt::Display for CollectionError {
38    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
39        match self {
40            Self::TooFew { min, actual } => {
41                write!(
42                    f,
43                    "collection is too small: minimum is {min}, actual is {actual}"
44                )
45            }
46            Self::TooMany { max, actual } => {
47                write!(
48                    f,
49                    "collection is too large: maximum is {max}, actual is {actual}"
50                )
51            }
52            Self::InvalidBounds { min, max } => {
53                write!(f, "invalid bounds: MIN ({min}) must not exceed MAX ({max})")
54            }
55            Self::ZeroCapacity => write!(f, "capacity must be greater than zero"),
56            Self::Duplicate => write!(f, "collection contains a duplicate key or element"),
57        }
58    }
59}
60
61#[cfg(feature = "std")]
62impl std::error::Error for CollectionError {}
63
64#[cfg(test)]
65mod tests {
66    use super::CollectionError;
67    use alloc::string::ToString;
68
69    #[test]
70    fn display_too_few() {
71        assert_eq!(
72            CollectionError::TooFew { min: 2, actual: 0 }.to_string(),
73            "collection is too small: minimum is 2, actual is 0"
74        );
75    }
76
77    #[test]
78    fn display_too_many() {
79        assert_eq!(
80            CollectionError::TooMany { max: 5, actual: 6 }.to_string(),
81            "collection is too large: maximum is 5, actual is 6"
82        );
83    }
84
85    #[test]
86    fn display_invalid_bounds() {
87        assert_eq!(
88            CollectionError::InvalidBounds { min: 5, max: 3 }.to_string(),
89            "invalid bounds: MIN (5) must not exceed MAX (3)"
90        );
91    }
92
93    #[test]
94    fn display_zero_capacity() {
95        assert_eq!(
96            CollectionError::ZeroCapacity.to_string(),
97            "capacity must be greater than zero"
98        );
99    }
100
101    #[test]
102    fn display_duplicate() {
103        assert_eq!(
104            CollectionError::Duplicate.to_string(),
105            "collection contains a duplicate key or element"
106        );
107    }
108}
reliakit_collections/error.rs

reliakit_collections/
error.rs
