From 9355f20616435f685831a63e6dfbdcca49c08a2b Mon Sep 17 00:00:00 2001
From: Gabriel Kaszewski <gabrielkaszewski@gmail.com>
Date: Tue, 30 Jun 2026 01:49:30 +0200
Subject: [PATCH] fix: send Undo(Block) on unblock_actor

---
 CHANGELOG.md          |  8 ++++++++
 Cargo.toml            |  2 +-
 src/service/follow.rs | 25 +++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index efb6edd..4552d94 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## [0.4.1] — 2026-06-30
+
+### Bug fixes
+
+- `unblock_actor` now sends an `Undo(Block)` activity to the remote actor's inbox before removing them from the local blocklist, making unblocking AP-compliant.
+
+---
+
 ## [0.4.0] — 2026-05-30
 
 ### Breaking changes
diff --git a/Cargo.toml b/Cargo.toml
index a04aedd..cfbe0f6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "k-ap"
-version = "0.4.0"
+version = "0.4.1"
 edition = "2024"
 description = "Generic ActivityPub protocol layer"
 license = "MIT"
diff --git a/src/service/follow.rs b/src/service/follow.rs
index ac2857e..d8d8933 100644
--- a/src/service/follow.rs
+++ b/src/service/follow.rs
@@ -328,7 +328,32 @@ impl ActivityPubService {
         let data = self.federation_config.to_request_data();
         data.blocklist_repo
             .remove_blocked_actor(local_user_id, actor_url)
+            .await?;
+        let local_actor = get_local_actor(local_user_id, &data)
             .await
+            .map_err(|e| anyhow::anyhow!("{e}"))?;
+        if let Ok(Some(remote_actor)) = data.actor_repo.get_remote_actor(actor_url).await {
+            let block = crate::activities::BlockActivity {
+                id: activity_url(&self.base_url).map_err(|e| anyhow::anyhow!("{e}"))?,
+                kind: Default::default(),
+                actor: ObjectId::from(local_actor.ap_id.clone()),
+                object: Url::parse(actor_url)?,
+            };
+            let undo = UndoActivity {
+                id: activity_url(&self.base_url).map_err(|e| anyhow::anyhow!("{e}"))?,
+                kind: Default::default(),
+                actor: ObjectId::from(local_actor.ap_id.clone()),
+                object: serde_json::to_value(&block).map_err(|e| anyhow::anyhow!("{e}"))?,
+            };
+            let inbox = Url::parse(&remote_actor.inbox_url)?;
+            let (json, sends, inboxes) = self
+                .prepare_broadcast(&data, &local_actor, vec![inbox], undo)
+                .await?;
+            self.dispatch_deliveries(&data, &local_actor, inboxes, sends, json)
+                .await?;
+            tracing::info!(actor = %actor_url, "sent Undo(Block)");
+        }
+        Ok(())
     }
 
     pub async fn get_blocked_actors(