diff --git a/libpijul/src/apply/edge.rs b/libpijul/src/apply/edge.rs
index 12b586f..2377ad7 100644
--- a/libpijul/src/apply/edge.rs
+++ b/libpijul/src/apply/edge.rs
@@ -106,6 +106,9 @@ where
         }
     }
     if n.flag.contains(EdgeFlags::DELETED) {
+        // We're deleting a vertex n.to. If n has children or parents
+        // that are unknown to the patch we're applying, zombify these
+        // children and parents.
         collect_zombie_context(txn, graph, &mut ws.missing_context, inode, n, change, known)
             .map_err(LocalApplyError::from_missing)?;
     }
@@ -128,7 +131,7 @@ where
     // edge points towards a zombie.
     for v in iter_deleted_parents(txn, graph, source)? {
         let v = v?;
-        let intro = v.introduced_by();
+        let intro = v.dest().change;
         if !known(&txn.get_external(&intro)?.unwrap().into()) {
             zombies.push(intro)
         }
@@ -142,7 +145,7 @@ where
         }
         for v in iter_deleted_parents(txn, graph, target)? {
             let v = v?;
-            let intro = v.introduced_by();
+            let intro = v.dest().change;
             debug!("known {:?} ?", intro);
             if !known(&txn.get_external(&intro)?.unwrap().into()) {
                 zombies.push(intro)
@@ -335,7 +338,7 @@ where
             }
             if v.flag().contains(EdgeFlags::PARENT) {
                 // Unwrap ok, since `v` is in the channel.
-                let intro = txn.get_external(&v.introduced_by())?.unwrap().into();
+                let intro = txn.get_external(&v.dest().change)?.unwrap().into();
                 if !known(&intro) {
                     debug!("unknown: {:?}", v);
                     unknown_parents.push((dest_vertex, *v))
diff --git a/libpijul/src/changestore/mod.rs b/libpijul/src/changestore/mod.rs
index ea272ee..f3c42e2 100644
--- a/libpijul/src/changestore/mod.rs
+++ b/libpijul/src/changestore/mod.rs
@@ -55,6 +55,7 @@ pub trait ChangeStore {
         Ok(self.get_change(hash)?.hashed.changes)
     }
     fn knows(&self, hash0: &Hash, hash1: &Hash) -> Result<bool, Self::Error> {
+        debug!("knows: {:?} {:?}", hash0, hash1);
         Ok(self.get_change(hash0)?.knows(hash1))
     }
     fn has_edge(
diff --git a/libpijul/src/find_alive.rs b/libpijul/src/find_alive.rs
index e763914..b2387d0 100644
--- a/libpijul/src/find_alive.rs
+++ b/libpijul/src/find_alive.rs
@@ -40,6 +40,8 @@ pub(crate) fn find_alive_down<'a, T: GraphTxnT>(
                     if let Some(c) = c {
                         st.extend(c.iter().cloned());
                     } else {
+                        // A `None` in the cache means that the vertex
+                        // itself (the cache key) is alive.
                         st.insert(*vertex);
                     }
                 }
diff --git a/libpijul/src/unrecord/mod.rs b/libpijul/src/unrecord/mod.rs
index a232431..109e0f8 100644
--- a/libpijul/src/unrecord/mod.rs
+++ b/libpijul/src/unrecord/mod.rs
@@ -443,10 +443,13 @@ fn unapply_edges<T: GraphMutTxnT + TreeTxnT, P: ChangeStore>(
             &edge.reverse(Some(ext)),
             |a, b| reintro.contains(&(a, b)),
             |h| {
+                if h == &hash {
+                    return true
+                }
                 if edge.previous.contains(EdgeFlags::DELETED) {
-                    // When reintroducing a deleted flag, check whether
-                    // the re-introduction patch knows about the alive
-                    // edges around the target.
+                    // When reintroducing an edge that was deleted,
+                    // check whether the re-introduction patch knows
+                    // about the alive edges around the target.
                     changes
                         .knows(edge.introduced_by.as_ref().unwrap_or(&hash), h)
                         .unwrap()
diff --git a/pijul/src/commands/credit.rs b/pijul/src/commands/credit.rs
index f86c5cb..cf1a6fb 100644
--- a/pijul/src/commands/credit.rs
+++ b/pijul/src/commands/credit.rs
@@ -50,13 +50,10 @@ impl Credit {
             let path = root.strip_prefix(&repo_path.as_path())?.to_str().unwrap();
             txn.follow_oldest_path(&repo.changes, &channel, &path)?
         };
->>>>>>> 1 [YXAVFTPP]
->>>>>>> 1 [YXAVFTPP]
         std::mem::drop(txn);
 
         super::pager(repo.config.pager.as_ref());
 
-<<<<<<< 1
         match libpijul::output::output_file(
             &repo.changes,
             &txn_,
@@ -179,8 +176,3 @@ impl<W: std::io::Write, T: TxnTExt> VertexBuffer for Creditor<W, T> {
         Ok(())
     }
 }
-======= 1 [U6TQX5Z2]
->>>>>>> 2 [U6TQX5Z2]
-        super::pager(repo.config.pager.as_ref());
-<<<<<<< 2
-<<<<<<< 1
diff --git a/pijul/src/remote/mod.rs b/pijul/src/remote/mod.rs
index c8a101a..667b1d6 100644
--- a/pijul/src/remote/mod.rs
+++ b/pijul/src/remote/mod.rs
@@ -721,6 +721,7 @@ impl RemoteRepo {
             })
         } else {
             let mut to_download: Vec<CS> = Vec::new();
+            let mut to_download_ = HashSet::new();
             for x in txn.iter_rev_remote(&remote_ref.lock().remote, None)? {
                 let (_, p) = x?;
                 let h: Hash = p.a.into();
@@ -732,7 +733,10 @@ impl RemoteRepo {
                     break;
                 }
                 if txn.get_revchanges(&current_channel, &h).unwrap().is_none() {
-                    to_download.push(CS::Change(h));
+                    let h = CS::Change(h);
+                    if to_download_.insert(h.clone()) {
+                        to_download.push(h);
+                    }
                 }
             }
 
@@ -742,7 +746,9 @@ impl RemoteRepo {
                 // In all cases, add this new change/state/tag to `to_download`.
                 let ch = CS::Change(*h);
                 if txn.get_revchanges(&current_channel, h).unwrap().is_none() {
-                    to_download.push(ch.clone());
+                    if to_download_.insert(ch.clone()) {
+                        to_download.push(ch.clone());
+                    }
                     if *is_tag {
                         to_download.push(CS::State(*m));
                     }