es_entity/
error.rs

1//! Types for working with errors produced by es-entity.
2
3use thiserror::Error;
4
5/// Error type for entity hydration failures (reconstructing entities from events).
6#[derive(Error, Debug)]
7pub enum EntityHydrationError {
8    #[error("EntityHydrationError - UninitializedFieldError: {0}")]
9    UninitializedFieldError(#[from] derive_builder::UninitializedFieldError),
10    #[error("EntityHydrationError - Deserialization: {0}")]
11    EventDeserialization(#[from] serde_json::Error),
12}
13
14#[derive(Error, Debug)]
15#[error("CursorDestructureError: couldn't turn {0} into {1}")]
16pub struct CursorDestructureError(&'static str, &'static str);
17
18impl From<(&'static str, &'static str)> for CursorDestructureError {
19    fn from((name, variant): (&'static str, &'static str)) -> Self {
20        Self(name, variant)
21    }
22}
23
24#[doc(hidden)]
25/// Extracts the conflicting value from a PostgreSQL constraint violation detail message.
26///
27/// PostgreSQL formats unique violation details as:
28/// `Key (column)=(value) already exists.`
29///
30/// Returns `None` if the detail is missing or doesn't match the expected format.
31///
32/// **Security note:** the extracted value is attacker-influenced input that
33/// was rejected by a unique constraint and may be PII (e.g. an email
34/// address). Returning it to untrusted API clients enables user
35/// enumeration; logging it may place PII in log pipelines.
36pub fn parse_constraint_detail_value(detail: Option<&str>) -> Option<String> {
37    let detail = detail?;
38    let start = detail.find("=(")? + 2;
39    let end = detail.rfind(") already")?;
40    if start <= end {
41        Some(detail[start..end].to_string())
42    } else {
43        None
44    }
45}
46
47#[doc(hidden)]
48/// Extracts the conflicting value from a database error's constraint violation.
49///
50/// Downcasts to [`sqlx::postgres::PgDatabaseError`], reads its `detail()`,
51/// and parses the conflicting value.
52///
53/// **Security note:** see [`parse_constraint_detail_value`] — the returned
54/// value may be PII and must not be exposed to untrusted clients.
55pub fn extract_constraint_value(db_err: &dyn sqlx::error::DatabaseError) -> Option<String> {
56    let pg_err = db_err.try_downcast_ref::<sqlx::postgres::PgDatabaseError>()?;
57    parse_constraint_detail_value(pg_err.detail())
58}
59
60/// The kind of database constraint behind a classified `ConstraintViolation`.
61///
62/// Returned by the generated `{Entity}Constraint::kind()` method.
63#[derive(Debug, Clone, Copy, PartialEq, Eq)]
64pub enum ConstraintKind {
65    Unique,
66    ForeignKey,
67    Check,
68}
69
70#[doc(hidden)]
71/// `true` when the database error is a violation kind the generated repo
72/// classifiers surface as `ConstraintViolation`: unique (SQLSTATE 23505),
73/// foreign key (23503), or check (23514). `NOT NULL` (23502) and exclusion
74/// (23P01) violations are not classified and surface as `Sqlx`.
75pub fn is_classified_constraint_violation(db_err: &dyn sqlx::error::DatabaseError) -> bool {
76    db_err.is_unique_violation() || db_err.is_foreign_key_violation() || db_err.is_check_violation()
77}
78
79#[doc(hidden)]
80/// Wrapper used by generated code to format not-found values.
81/// Prefers `Display` over `Debug` via inherent-vs-trait method resolution.
82pub struct NotFoundValue<'a, T: ?Sized>(pub &'a T);
83
84impl<T: std::fmt::Display + ?Sized> NotFoundValue<'_, T> {
85    pub fn to_not_found_value(&self) -> String {
86        self.0.to_string()
87    }
88}
89
90#[doc(hidden)]
91pub trait ToNotFoundValueFallback {
92    fn to_not_found_value(&self) -> String;
93}
94
95impl<T: std::fmt::Debug + ?Sized> ToNotFoundValueFallback for NotFoundValue<'_, T> {
96    fn to_not_found_value(&self) -> String {
97        format!("{:?}", self.0)
98    }
99}
100
101#[cfg(test)]
102mod tests {
103    use super::*;
104
105    #[test]
106    fn parse_simple_uuid_value() {
107        let detail = Some("Key (id)=(550e8400-e29b-41d4-a716-446655440000) already exists.");
108        assert_eq!(
109            parse_constraint_detail_value(detail),
110            Some("550e8400-e29b-41d4-a716-446655440000".to_string())
111        );
112    }
113
114    #[test]
115    fn parse_string_value() {
116        let detail = Some("Key (email)=(user@example.com) already exists.");
117        assert_eq!(
118            parse_constraint_detail_value(detail),
119            Some("user@example.com".to_string())
120        );
121    }
122
123    #[test]
124    fn parse_composite_key_value() {
125        let detail = Some("Key (tenant_id, email)=(abc, user@example.com) already exists.");
126        assert_eq!(
127            parse_constraint_detail_value(detail),
128            Some("abc, user@example.com".to_string())
129        );
130    }
131
132    #[test]
133    fn parse_none_detail() {
134        assert_eq!(parse_constraint_detail_value(None), None);
135    }
136
137    #[test]
138    fn parse_unexpected_format() {
139        let detail = Some("something unexpected");
140        assert_eq!(parse_constraint_detail_value(detail), None);
141    }
142
143    #[test]
144    fn parse_value_containing_parentheses() {
145        let detail = Some("Key (name)=(foo (bar)) already exists.");
146        assert_eq!(
147            parse_constraint_detail_value(detail),
148            Some("foo (bar)".to_string())
149        );
150    }
151
152    #[test]
153    fn parse_empty_value() {
154        let detail = Some("Key (col)=() already exists.");
155        assert_eq!(parse_constraint_detail_value(detail), Some("".to_string()));
156    }
157
158    #[test]
159    fn not_found_value_uses_display_when_available() {
160        #[allow(unused_imports)]
161        use crate::ToNotFoundValueFallback;
162
163        // String implements Display - should get clean output
164        let val = "hello";
165        assert_eq!(NotFoundValue(val).to_not_found_value(), "hello");
166
167        // i32 implements Display
168        let num = 42;
169        assert_eq!(NotFoundValue(&num).to_not_found_value(), "42");
170    }
171
172    #[test]
173    fn not_found_value_falls_back_to_debug() {
174        use crate::ToNotFoundValueFallback;
175
176        // A type with Debug but no Display
177        #[derive(Debug)]
178        #[allow(dead_code)]
179        struct OnlyDebug(i32);
180
181        let val = OnlyDebug(7);
182        assert_eq!(NotFoundValue(&val).to_not_found_value(), "OnlyDebug(7)");
183    }
184}
es_entity/error.rs

es_entity/
error.rs
