patch: Correctly merge review edits

Signed-off-by: Alexis Sellier <alexis@radicle.xyz>

Cargo.lock

@@ -2176,6 +2176,7 @@ dependencies = [
  "log",
  "multibase",
  "nonempty 0.8.0",
+ "num-traits",
  "olpc-cjson",
  "once_cell",
  "pretty_assertions",

radicle-crdt/src/clock.rs

@@ -1,3 +1,4 @@
+use num_traits::Bounded;
 use serde::{Deserialize, Serialize};
 
 use crate::ord::Max;
@@ -43,3 +44,13 @@ impl From<u64> for Lamport {
         }
     }
 }
+
+impl Bounded for Lamport {
+    fn min_value() -> Self {
+        Self::from(u64::min_value())
+    }
+
+    fn max_value() -> Self {
+        Self::from(u64::max_value())
+    }
+}

radicle-crdt/src/lwwmap.rs

@@ -64,6 +64,10 @@ impl<K: Ord, V: Semilattice, C: PartialOrd + Ord> LWWMap<K, V, C> {
             .filter_map(|(k, v)| v.get().as_ref().map(|v| (k, v)))
     }
 
+    pub fn len(&self) -> usize {
+        self.iter().count()
+    }
+
     pub fn is_empty(&self) -> bool {
         self.iter().next().is_none()
     }

radicle-crdt/src/ord.rs

@@ -56,6 +56,16 @@ impl<T: PartialOrd> Semilattice for Max<T> {
     }
 }
 
+impl<T: Bounded> Bounded for Max<T> {
+    fn min_value() -> Self {
+        Self::from(T::min_value())
+    }
+
+    fn max_value() -> Self {
+        Self::from(T::max_value())
+    }
+}
+
 #[allow(clippy::derive_ord_xor_partial_ord)]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Ord, Serialize, Deserialize)]
 pub struct Min<T>(pub T);

radicle/Cargo.toml

@@ -19,6 +19,7 @@ cyphernet = { version = "0", optional = true }
 fastrand = { version = "1.8.0" }
 git-ref-format = { version = "0", features = ["serde", "macro"] }
 multibase = { version = "0.9.1" }
+num-traits = { version = "0.2.15", default-features = false, features = ["std"] }
 log = { version = "0.4.17", features = ["std"] }
 once_cell = { version = "1.13" }
 olpc-cjson = { version = "0.1.1" }

radicle/src/cob/common.rs

@@ -2,6 +2,7 @@ use std::fmt;
 use std::str::FromStr;
 use std::time::{SystemTime, UNIX_EPOCH};
 
+use num_traits::Bounded;
 use serde::{Deserialize, Serialize};
 
 use crate::prelude::*;
@@ -57,6 +58,20 @@ impl std::ops::Add<u64> for Timestamp {
     }
 }
 
+impl Bounded for Timestamp {
+    fn min_value() -> Self {
+        Self {
+            seconds: u64::min_value(),
+        }
+    }
+
+    fn max_value() -> Self {
+        Self {
+            seconds: u64::max_value(),
+        }
+    }
+}
+
 #[derive(thiserror::Error, Debug)]
 pub enum ReactionError {
     #[error("invalid reaction")]

radicle/src/cob/patch.rs

@@ -9,7 +9,7 @@ use std::str::FromStr;
 use once_cell::sync::Lazy;
 use radicle_crdt as crdt;
 use radicle_crdt::clock;
-use radicle_crdt::{ActorId, ChangeId, LWWMap, LWWReg, LWWSet, Max, Redactable, Semilattice};
+use radicle_crdt::{ActorId, ChangeId, LWWReg, LWWSet, Max, Redactable, Semilattice};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 
@@ -271,14 +271,17 @@ impl Patch {
                 ref inline,
             } => {
                 // TODO(cloudhead): Test review on redacted revision.
-                // TODO(cloudhead): Test that updating a review only requires the fields that we
-                // want to update.
                 if let Some(Redactable::Present(revision)) = self.revisions.get_mut(&revision) {
-                    revision.reviews.insert(
-                        change.author,
-                        Review::new(verdict, comment.to_owned(), inline.to_owned(), timestamp),
-                        change.clock,
-                    );
+                    revision
+                        .reviews
+                        .entry(change.author)
+                        .or_default()
+                        .merge(Review::new(
+                            verdict,
+                            comment.to_owned(),
+                            inline.to_owned(),
+                            timestamp,
+                        ));
                 } else {
                     return Err(ApplyError::Missing(revision));
                 }
@@ -360,7 +363,7 @@ pub struct Revision {
     /// Merges of this revision into other repositories.
     pub merges: LWWSet<Max<Merge>>,
     /// Reviews of this revision's changes (one per actor).
-    pub reviews: LWWMap<ActorId, Review>,
+    pub reviews: BTreeMap<ActorId, Review>,
     /// When this revision was created.
     pub timestamp: Timestamp,
 }
@@ -373,7 +376,7 @@ impl Revision {
             oid,
             discussion: Thread::default(),
             merges: LWWSet::default(),
-            reviews: LWWMap::default(),
+            reviews: BTreeMap::default(),
             timestamp,
         }
     }
@@ -470,7 +473,7 @@ pub struct CodeComment {
 }
 
 /// A patch review on a revision.
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Default, Clone, PartialEq, Eq)]
 pub struct Review {
     /// Review verdict.
     pub verdict: LWWReg<Option<Verdict>>,
@@ -1019,13 +1022,66 @@ mod test {
         let id = patch.id;
         let patch = patches.get(&id).unwrap().unwrap();
         let (_, revision) = patch.latest().unwrap();
-        assert_eq!(revision.reviews.iter().count(), 1);
+        assert_eq!(revision.reviews.len(), 1);
 
         let review = revision.reviews.get(signer.public_key()).unwrap();
         assert_eq!(review.verdict(), Some(Verdict::Accept));
         assert_eq!(review.comment(), Some("LGTM"));
     }
 
+    #[test]
+    fn test_patch_review_edit() {
+        let tmp = tempfile::tempdir().unwrap();
+        let (_, signer, project) = test::setup::context(&tmp);
+        let base = git::Oid::from_str("cb18e95ada2bb38aadd8e6cef0963ce37a87add3").unwrap();
+        let oid = git::Oid::from_str("518d5069f94c03427f694bb494ac1cd7d1339380").unwrap();
+        let mut patches = Patches::open(*signer.public_key(), &project).unwrap();
+        let mut patch = patches
+            .create(
+                "My first patch",
+                "Blah blah blah.",
+                MergeTarget::Delegates,
+                base,
+                oid,
+                &[],
+                &signer,
+            )
+            .unwrap();
+
+        let (rid, _) = patch.latest().unwrap();
+        let rid = *rid;
+
+        patch
+            .review(
+                rid,
+                Some(Verdict::Accept),
+                Some("LGTM".to_owned()),
+                vec![],
+                &signer,
+            )
+            .unwrap();
+        patch
+            .review(rid, Some(Verdict::Reject), None, vec![], &signer)
+            .unwrap(); // Overwrite the verdict.
+
+        let id = patch.id;
+        let mut patch = patches.get_mut(&id).unwrap();
+        let (_, revision) = patch.latest().unwrap();
+        assert_eq!(revision.reviews.len(), 1, "the reviews were merged");
+
+        let review = revision.reviews.get(signer.public_key()).unwrap();
+        assert_eq!(review.verdict(), Some(Verdict::Reject));
+        assert_eq!(review.comment(), Some("LGTM"));
+
+        patch
+            .review(rid, None, Some("Whoops!".to_owned()), vec![], &signer)
+            .unwrap(); // Overwrite the comment.
+        let (_, revision) = patch.latest().unwrap();
+        let review = revision.reviews.get(signer.public_key()).unwrap();
+        assert_eq!(review.verdict(), Some(Verdict::Reject));
+        assert_eq!(review.comment(), Some("Whoops!"));
+    }
+
     #[test]
     fn test_patch_update() {
         let tmp = tempfile::tempdir().unwrap();