persistant_relational/
error.rs

1// SPDX-License-Identifier: MIT OR Apache-2.0
2use std::fmt;
3
4/// Why a relational operation failed, classified so a caller can branch without parsing driver
5/// text (Humboldt hand-maps constraint names in at least seven places today). Plain data.
6#[derive(Debug, Clone, PartialEq, Eq)]
7#[non_exhaustive]
8pub enum RelError {
9    /// A unique or primary-key constraint rejected the statement.
10    UniqueViolation {
11        /// The constraint's name, if the server reports it.
12        constraint: Option<String>,
13    },
14    /// A foreign-key constraint rejected the statement.
15    ForeignKeyViolation {
16        /// The constraint's name, if the server reports it.
17        constraint: Option<String>,
18    },
19    /// A check constraint (or NOT NULL) rejected the statement.
20    CheckViolation {
21        /// The constraint's name, if the server reports it.
22        constraint: Option<String>,
23    },
24    /// The transaction could not be serialised; retrying it may succeed.
25    Serialization,
26    /// The server chose this transaction as a deadlock victim; retrying it may succeed.
27    Deadlock,
28    /// The server could not be reached or went away.
29    Unavailable(String),
30    /// The backend cannot do this, and says so rather than approximating.
31    Unsupported(String),
32    /// A call did not finish within the configured per-call bound and was cut off. For a statement
33    /// outside a transaction, whether it took effect is unknown; a transaction that saw one is
34    /// rolled back and refuses to commit.
35    Timeout {
36        /// The bound that expired.
37        after: std::time::Duration,
38    },
39    /// Any other failure; the text is the driver's.
40    Backend(String),
41}
42
43impl fmt::Display for RelError {
44    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
45        let c = |c: &Option<String>| c.as_deref().unwrap_or("?").to_string();
46        match self {
47            RelError::UniqueViolation { constraint } => {
48                write!(f, "unique violation ({})", c(constraint))
49            }
50            RelError::ForeignKeyViolation { constraint } => {
51                write!(f, "foreign key violation ({})", c(constraint))
52            }
53            RelError::CheckViolation { constraint } => {
54                write!(f, "check violation ({})", c(constraint))
55            }
56            RelError::Serialization => f.write_str("serialization failure"),
57            RelError::Deadlock => f.write_str("deadlock detected"),
58            RelError::Unavailable(m) => write!(f, "database unavailable: {m}"),
59            RelError::Unsupported(m) => write!(f, "database does not support: {m}"),
60            RelError::Timeout { after } => write!(f, "database call timed out after {after:?}"),
61            RelError::Backend(m) => write!(f, "database: {m}"),
62        }
63    }
64}
65
66impl std::error::Error for RelError {}
persistant_relational/error.rs

persistant_relational/
error.rs
