Add Diesel error variant

src/util/error.rs

@@ -233,6 +233,13 @@ impl<T, E: Into<Error>> Contextualize<Result<T, Error>> for Result<T, E> {
     }
 }
 
+impl<T> Contextualize<Result<T, Error>> for Option<T> {
+    #[track_caller]
+    fn err_context(self, context: impl Into<String>) -> Result<T, Error> {
+        self.ok_or(Error::new_here(ErrorType::Error(context.into())))
+    }
+}
+
 impl<E: Into<Error>> Contextualize<Error> for E {
     #[track_caller]
     fn err_context(self, context: impl Into<String>) -> Error {
@@ -242,6 +249,13 @@ impl<E: Into<Error>> Contextualize<Error> for E {
 
 #[derive(Debug, Clone, thiserror::Error, Deserialize, Serialize)]
 pub enum ErrorType {
+    // Using string to represent Diesel errors, because Diesel's Error type is not `Serialize`,
+    // and Diesel is only available on the server
+    #[error("Database error: {0}")]
+    Database(String),
+
+    #[error("{0}")]
+    Error(String),
 }
 
 impl From<ErrorType> for Error {
@@ -250,3 +264,11 @@ impl From<ErrorType> for Error {
         Error::new_here(err)
     }
 }
+
+#[cfg(feature = "server")]
+impl From<diesel::result::Error> for Error {
+    #[track_caller]
+    fn from(err: diesel::result::Error) -> Self {
+        Error::new_here(ErrorType::Database(format!("{err}")))
+    }
+}