add check for uniqueness violation in account creation

src/users.rs

@@ -17,7 +17,7 @@ pub struct User {
 }
 
 #[derive(Debug, Clone, sqlx::FromRow, sqlx::Encode)]
-struct DbUser {
+pub(crate) struct DbUser {
     id: Uuid,
     username: String,
     displayname: Option<String>,
@@ -54,7 +54,7 @@ pub async fn create_user(
         .to_string();
 
     let id = Uuid::new_v4();
-    let id_bytes = sqlx::types::Uuid::from_u128(id.as_u128());
+    let id_bytes = id.as_bytes().as_slice();
     let res = sqlx::query(CREATE_QUERY)
         .bind(id_bytes)
         .bind(username)
@@ -76,7 +76,9 @@ pub async fn create_user(
         }
         Err(sqlx::Error::Database(db)) => {
             if let Some(exit) = db.code() {
-                if exit.parse().unwrap_or(0) == 2067u32 {
+                let exit = exit.parse().unwrap_or(0u32);
+                // https://www.sqlite.org/rescode.html codes for unique constraint violations:
+                if exit == 2067u32 || exit == 1555 {
                     Err(CreateUserErrorKind::AlreadyExists.into())
                 } else {
                     Err(CreateUserErrorKind::Unknown.into())
@@ -85,7 +87,7 @@ pub async fn create_user(
                 Err(CreateUserErrorKind::Unknown.into())
             }
         }
-        _ => unreachable!(),
+        _ => Err(CreateUserErrorKind::Unknown.into()),
     }
 }
 
@@ -97,9 +99,7 @@ pub struct CreateUserError(#[from] CreateUserErrorKind);
 #[non_exhaustive]
 pub enum CreateUserErrorKind {
     AlreadyExists,
-    #[error(
+    #[error(desc = "Usernames must be less than 20 characters long")]
-        desc = "Usernames must be less than 20 characters and contain only ascii letters, numbers, and dashes."
-    )]
     BadUsername,
     PasswordMismatch,
     MissingFields,