feat: Add support for 3pid management

src/service/mailer/messages.rs

@@ -8,7 +8,8 @@ pub trait MessageTemplate: Template {
 #[derive(Template)]
 #[template(path = "mail/change_email.txt")]
 pub struct ChangeEmail<'a> {
-	pub user_id: &'a UserId,
+	pub server_name: &'a str,
+	pub user_id: Option<&'a UserId>,
 	pub verification_link: String,
 }
 

src/service/templates/mail/change_email.txt

@@ -2,9 +2,12 @@
 
 {% block content -%}
 Hello!
-
+{% if let Some(user_id) = user_id -%}
 Somebody, probably you, tried to associate this email address with the Matrix account {{ user_id }}.
-If that's your account, and this is your email address, click this link to proceed:
+{%- else -%}
+Somebody, probably you, tried to associate this email address with a Matrix account on {{ server_name }}.
+{%- endif %}
+If that was you, and this is your email address, click this link to proceed:
     {{ verification_link }}
 Otherwise, you can ignore this email. The above link will expire in one hour.
 {%- endblock %}

src/service/threepid/mod.rs

@@ -227,15 +227,15 @@ impl Service {
 	///
 	/// [`Self::get_localpart_for_email`] may be used if only the email is
 	/// known.
-	pub async fn disassociate_localpart_email(&self, localpart: &str) {
-		let email = self
-			.get_email_for_localpart(localpart)
-			.await
-			.expect("localpart has no email associated");
+	pub async fn disassociate_localpart_email(&self, localpart: &str) -> Option<Address> {
+		let email = self.get_email_for_localpart(localpart).await?;
+
 		self.db.localpart_email.remove(localpart);
 		self.db
 			.email_localpart
 			.remove(<Address as AsRef<str>>::as_ref(&email));
+
+		Some(email)
 	}
 
 	/// Get the email associated with a localpart, if one exists.