Make email address lookups case-insensitive

crates/storage-pg/migrations/20250708155857_idx_user_emails_lower_email.sql

@@ -0,0 +1,11 @@
+-- no-transaction
+-- Copyright 2025 New Vector Ltd.
+--
+-- SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+-- Please see LICENSE in the repository root for full details.
+
+-- When we're looking up an email address, we want to be able to do a case-insensitive
+-- lookup, so we index the email address lowercase and request it like that
+CREATE INDEX CONCURRENTLY
+  user_emails_lower_email_idx
+  ON user_emails (LOWER(email));

crates/storage-pg/src/user/email.rs

@@ -15,7 +15,7 @@ use mas_storage::{
     user::{UserEmailFilter, UserEmailRepository},
 };
 use rand::RngCore;
-use sea_query::{Expr, PostgresQueryBuilder, Query, enum_def};
+use sea_query::{Expr, Func, PostgresQueryBuilder, Query, SimpleExpr, enum_def};
 use sea_query_binder::SqlxBinder;
 use sqlx::PgConnection;
 use ulid::Ulid;
@@ -110,10 +110,13 @@ impl Filter for UserEmailFilter<'_> {
             .add_option(self.user().map(|user| {
                 Expr::col((UserEmails::Table, UserEmails::UserId)).eq(Uuid::from(user.id))
             }))
-            .add_option(
-                self.email()
-                    .map(|email| Expr::col((UserEmails::Table, UserEmails::Email)).eq(email)),
-            )
+            .add_option(self.email().map(|email| {
+                SimpleExpr::from(Func::lower(Expr::col((
+                    UserEmails::Table,
+                    UserEmails::Email,
+                ))))
+                .eq(Func::lower(email))
+            }))
     }
 }
 
@@ -175,7 +178,7 @@ impl UserEmailRepository for PgUserEmailRepository<'_> {
                      , created_at
                 FROM user_emails
 
-                WHERE user_id = $1 AND email = $2
+                WHERE user_id = $1 AND LOWER(email) = LOWER($2)
             "#,
             Uuid::from(user.id),
             email,
@@ -209,7 +212,7 @@ impl UserEmailRepository for PgUserEmailRepository<'_> {
                      , email
                      , created_at
                 FROM user_emails
-                WHERE email = $1
+                WHERE LOWER(email) = LOWER($1)
             "#,
             email,
         )

crates/storage-pg/src/user/tests.rs

@@ -268,6 +268,10 @@ async fn test_user_repo_find_by_username(pool: PgPool) {
 async fn test_user_email_repo(pool: PgPool) {
     const USERNAME: &str = "john";
     const EMAIL: &str = "[email protected]";
+    // This is what is stored in the database, making sure that:
+    //  1. we don't normalize the email address when storing it
+    //  2. looking it up is case-incensitive
+    const UPPERCASE_EMAIL: &str = "[email protected]";
 
     let mut repo = PgRepository::from_pool(&pool).await.unwrap().boxed();
     let mut rng = ChaChaRng::seed_from_u64(42);
@@ -295,12 +299,12 @@ async fn test_user_email_repo(pool: PgPool) {
 
     let user_email = repo
         .user_email()
-        .add(&mut rng, &clock, &user, EMAIL.to_owned())
+        .add(&mut rng, &clock, &user, UPPERCASE_EMAIL.to_owned())
         .await
         .unwrap();
 
     assert_eq!(user_email.user_id, user.id);
-    assert_eq!(user_email.email, EMAIL);
+    assert_eq!(user_email.email, UPPERCASE_EMAIL);
 
     // Check the counts
     assert_eq!(repo.user_email().count(all).await.unwrap(), 1);
@@ -321,7 +325,7 @@ async fn test_user_email_repo(pool: PgPool) {
         .expect("user email was not found");
 
     assert_eq!(user_email.user_id, user.id);
-    assert_eq!(user_email.email, EMAIL);
+    assert_eq!(user_email.email, UPPERCASE_EMAIL);
 
     // Listing the user emails should work
     let emails = repo

crates/storage/src/user/email.rs

@@ -36,6 +36,8 @@ impl<'a> UserEmailFilter<'a> {
     }
 
     /// Filter for emails matching a specific email address
+    ///
+    /// The email address is case-insensitive
     #[must_use]
     pub fn for_email(mut self, email: &'a str) -> Self {
         self.email = Some(email);
@@ -81,6 +83,8 @@ pub trait UserEmailRepository: Send + Sync {
 
     /// Lookup an [`UserEmail`] by its email address for a [`User`]
     ///
+    /// The email address is case-insensitive
+    ///
     /// Returns `None` if no matching [`UserEmail`] was found
     ///
     /// # Parameters
@@ -95,6 +99,8 @@ pub trait UserEmailRepository: Send + Sync {
 
     /// Lookup an [`UserEmail`] by its email address
     ///
+    /// The email address is case-insensitive
+    ///
     /// Returns `None` if no matching [`UserEmail`] was found or if multiple
     /// [`UserEmail`] are found
     ///