impl AsRegex for LazyLock<Regex> (#361)

* impl AsRegex for LazyLock<Regex>

* Update changelog

CHANGELOG.md

@@ -1,5 +1,8 @@
 ## Changelog
 
+## Unreleased
+- Implement `AsRegex` for `std::sync::LazyLock<Regex>`
+
 ## 0.19.0 (2024/11/03)
 
 - Swap to using proc-macro-error-2 instead of proc-macro-error for Syn

validator/src/validation/regex.rs

@@ -1,7 +1,7 @@
 use std::borrow::Cow;
 use std::cell::OnceCell;
 use std::rc::Rc;
-use std::sync::{Arc, Mutex, OnceLock};
+use std::sync::{Arc, LazyLock, Mutex, OnceLock};
 
 use regex::Regex;
 
@@ -54,6 +54,12 @@ impl AsRegex for &Arc<Mutex<OnceLock<Regex>>> {
     }
 }
 
+impl AsRegex for LazyLock<Regex> {
+    fn as_regex(&self) -> Cow<Regex> {
+        Cow::Borrowed(self)
+    }
+}
+
 pub trait ValidateRegex {
     fn validate_regex(&self, regex: impl AsRegex) -> bool;
 }

validator_derive_tests/tests/regex.rs

@@ -1,6 +1,6 @@
 use once_cell::sync::Lazy;
 use std::cell::OnceCell;
-use std::sync::{Mutex, OnceLock};
+use std::sync::{LazyLock, Mutex, OnceLock};
 
 use regex::Regex;
 use validator::Validate;
@@ -10,6 +10,7 @@ static RE2: Lazy<Regex> = Lazy::new(|| Regex::new(r"^[a-z]{2}$").unwrap());
 static REGEX_ONCE_LOCK: OnceLock<Regex> = OnceLock::new();
 static REGEX_MUTEX_ONCE_CELL: Mutex<OnceCell<Regex>> = Mutex::new(OnceCell::new());
 static REGEX_MUTEX_ONCE_LOCK: Mutex<OnceLock<Regex>> = Mutex::new(OnceLock::new());
+static REGEX_LAZY_LOCK: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"^[a-z]{2}$").unwrap());
 
 #[test]
 fn can_validate_valid_regex() {
@@ -124,3 +125,18 @@ fn can_specify_mutex_once_lock_for_regex() {
     let t = TestStruct { val: "aaa".to_string() };
     assert!(t.validate().is_err());
 }
+
+#[test]
+fn can_specify_lazy_lock_for_regex() {
+    #[derive(Debug, Validate)]
+    struct TestStruct {
+        #[validate(regex(path = crate::REGEX_LAZY_LOCK))]
+        val: String,
+    }
+
+    let t = TestStruct { val: "aa".to_string() };
+    assert!(t.validate().is_ok());
+
+    let t = TestStruct { val: "aaa".to_string() };
+    assert!(t.validate().is_err());
+}