Fix signup duplicate upstream id

services/headless-lms/models/src/users.rs

@@ -128,7 +128,7 @@ pub async fn find_by_upstream_id(
 ) -> ModelResult<Option<User>> {
     let user = sqlx::query_as!(
         User,
-        "SELECT * FROM users WHERE upstream_id = $1",
+        "SELECT * FROM users WHERE upstream_id = $1 AND deleted_at IS NULL",
         upstream_id
     )
     .fetch_optional(conn)
@@ -209,7 +209,7 @@ pub async fn update_email_for_user(
 
     let user = sqlx::query_as!(
         User,
-        "SELECT * FROM users WHERE upstream_id = $1",
+        "SELECT * FROM users WHERE upstream_id = $1 AND deleted_at IS NULL",
         upstream_id
     )
     .fetch_one(&mut *tx)

services/headless-lms/server/src/controllers/auth.rs

@@ -218,24 +218,37 @@ pub async fn signup(
         .await;
         let user = match user {
             Ok(user) => user,
-            Err(error) => match error.error_type() {
-                ModelErrorType::DatabaseConstraint { constraint, .. }
-                    if constraint == "users_email"
-                        || constraint == "users_upstream_id_active_uniq_idx" =>
-                {
-                    // Either the email or the upstream_id already belongs to an existing account,
-                    // so the caller already has a courses.mooc.fi user.
-                    let token = skip_authorize();
-                    return token.authorized_ok(web::Json(SignupResponse::EmailAlreadyExists));
-                }
-                _ => {
-                    return Err(controller_err!(
-                        InternalServerError,
-                        "Failed to insert user.".to_string(),
-                        anyhow!(error)
-                    ));
-                }
-            },
+            Err(error)
+                if matches!(
+                    error.error_type(),
+                    ModelErrorType::DatabaseConstraint { constraint, .. }
+                        if constraint == "users_email"
+                ) =>
+            {
+                let token = skip_authorize();
+                return token.authorized_ok(web::Json(SignupResponse::EmailAlreadyExists));
+            }
+            // TMC synchronously posts the new user back to /api/v0/tmc-server/users/create
+            // while post_new_user_to_tmc is still in flight, so that callback has usually
+            // already created the user; continue with the existing row.
+            Err(error)
+                if matches!(
+                    error.error_type(),
+                    ModelErrorType::DatabaseConstraint { constraint, .. }
+                        if constraint == "users_upstream_id_active_uniq_idx"
+                ) =>
+            {
+                models::users::find_by_upstream_id(&mut conn, upstream_id)
+                    .await?
+                    .ok_or(error)?
+            }
+            Err(error) => {
+                return Err(controller_err!(
+                    InternalServerError,
+                    "Failed to insert user.".to_string(),
+                    anyhow!(error)
+                ));
+            }
         };
 
         let country = user_details.country.clone();