From 1949fce620a4d8f6ae9aa88412f5dbf4b7b0f089 Mon Sep 17 00:00:00 2001
From: Gabriel Kaszewski <gabrielkaszewski@gmail.com>
Date: Thu, 28 May 2026 00:30:58 +0200
Subject: [PATCH] fix: accept follow for migrated actor URLs via UUID lookup

---
 Cargo.lock        |  2 +-
 Cargo.toml        |  2 +-
 src/activities.rs | 18 +++++++++++++-----
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index cccbb67..e80a474 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1368,7 +1368,7 @@ dependencies = [
 
 [[package]]
 name = "k-ap"
-version = "0.1.6"
+version = "0.1.7"
 dependencies = [
  "activitypub_federation",
  "anyhow",
diff --git a/Cargo.toml b/Cargo.toml
index 45a4c1b..324b3de 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "k-ap"
-version = "0.1.7"
+version = "0.1.8"
 edition = "2024"
 description = "Generic ActivityPub protocol layer"
 license = "MIT"
diff --git a/src/activities.rs b/src/activities.rs
index 88e2e2f..7ba8246 100644
--- a/src/activities.rs
+++ b/src/activities.rs
@@ -65,12 +65,20 @@ impl Activity for FollowActivity {
                 )));
             }
         };
-        if target_domain != data.domain {
-            return Err(Error::bad_request(anyhow::anyhow!(
-                "follow target is not a local actor"
-            )));
+        if target_domain == data.domain {
+            return Ok(());
         }
-        Ok(())
+        // Domain mismatch — still accept if the UUID resolves to a local user.
+        // This handles domain migrations where remote servers have cached the old actor URL.
+        if let Some(uuid) = crate::urls::extract_user_id_from_url(target_url) {
+            if data.user_repo.find_by_id(uuid).await.ok().flatten().is_some() {
+                tracing::debug!(target = %target_url, local_domain = %data.domain, "accepting follow for migrated actor URL");
+                return Ok(());
+            }
+        }
+        Err(Error::bad_request(anyhow::anyhow!(
+            "follow target is not a local actor"
+        )))
     }
 
     async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {