Clear the dkim_works data when authservid candidates change

src/authres_handling.rs

@@ -156,6 +156,10 @@ async fn update_authservid_candidates(
         context
             .set_config(Config::AuthservidCandidates, Some(&new_config))
             .await?;
+        // Updating the authservid candidates may mean that we now consider
+        // emails as "failed" which "passed" previously, so we need to
+        // reset our expectation which DKIMs work.
+        clear_dkim_works(context).await?
     }
     Ok(())
 }
@@ -235,6 +239,14 @@ async fn set_dkim_works(context: &Context, from_domain: &str) -> Result<()> {
     Ok(())
 }
 
+async fn clear_dkim_works(context: &Context) -> Result<()> {
+    context
+        .sql
+        .execute("DELETE FROM sending_domains", paramsv![])
+        .await?;
+    Ok(())
+}
+
 fn parse_authservid_candidates_config(config: &Option<String>) -> HashSet<&str> {
     config
         .as_deref()