From 49fb8d442e08f1ebb03ebc9d992fa12dc0eacc8b Mon Sep 17 00:00:00 2001
From: Seongmin Lee <git@boltless.me>
Date: Wed, 5 Aug 2026 09:31:10 +0300
Subject: [PATCH] bobbin: handle PR records without `versions` field

Signed-off-by: Seongmin Lee <git@boltless.me>
---
 bobbin/crates/resolver/src/legacy_upgrade.rs | 24 ++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/bobbin/crates/resolver/src/legacy_upgrade.rs b/bobbin/crates/resolver/src/legacy_upgrade.rs
index dd15b59e..948b9e74 100644
--- a/bobbin/crates/resolver/src/legacy_upgrade.rs
+++ b/bobbin/crates/resolver/src/legacy_upgrade.rs
@@ -95,6 +95,7 @@ pub fn synthesize_created_at(bytes: &[u8], fallback_rfc3339: &str) -> Option<all
 enum FieldRule {
     DropIfEmptyString,
     NullToEmptyArray,
+    EnsureArray,
 }
 
 fn scrub_rules(nsid: &str) -> &'static [(&'static str, FieldRule)] {
@@ -104,7 +105,10 @@ fn scrub_rules(nsid: &str) -> &'static [(&'static str, FieldRule)] {
             ("add", FieldRule::NullToEmptyArray),
             ("delete", FieldRule::NullToEmptyArray),
         ],
-        "sh.tangled.repo.pull" => &[("rounds", FieldRule::NullToEmptyArray)],
+        "sh.tangled.repo.pull" => &[
+            ("rounds", FieldRule::NullToEmptyArray),
+            ("versions", FieldRule::EnsureArray),
+        ],
         _ => &[],
     }
 }
@@ -126,6 +130,7 @@ pub fn scrub_record_bytes<S: BosStr + AsRef<str>>(
                 Some((*field, *rule))
             }
             (FieldRule::NullToEmptyArray, Some(serde_json::Value::Null)) => Some((*field, *rule)),
+            (FieldRule::EnsureArray, Some(serde_json::Value::Null) | None) => Some((*field, *rule)),
             _ => None,
         })
         .collect();
@@ -136,7 +141,7 @@ pub fn scrub_record_bytes<S: BosStr + AsRef<str>>(
         FieldRule::DropIfEmptyString => {
             obj.remove(*field);
         }
-        FieldRule::NullToEmptyArray => {
+        FieldRule::NullToEmptyArray | FieldRule::EnsureArray => {
             obj.insert(
                 (*field).to_owned(),
                 serde_json::Value::Array(alloc::vec::Vec::new()),
@@ -622,6 +627,21 @@ mod tests {
         assert!(scrub_record_bytes(&nsid("sh.tangled.label.op"), json).is_none());
     }
 
+    #[test]
+    fn pull_decodes_with_only_rounds_or_only_versions() {
+        // rounds-only (pre-versions), versions-only (current) and an explicit null must
+        // all decode canon: the lexicon requires both arrays but no writer emits both.
+        for json in [
+            br#"{"$type":"sh.tangled.repo.pull","title":"t","createdAt":"2026-05-01T00:00:00Z","target":{"branch":"main","repo":"did:plc:scallop"},"rounds":[]}"#.as_slice(),
+            br#"{"$type":"sh.tangled.repo.pull","title":"t","createdAt":"2026-05-01T00:00:00Z","target":{"branch":"main","repo":"did:plc:scallop"},"versions":[]}"#.as_slice(),
+            br#"{"$type":"sh.tangled.repo.pull","title":"t","createdAt":"2026-05-01T00:00:00Z","target":{"branch":"main","repo":"did:plc:scallop"},"rounds":[],"versions":null}"#.as_slice(),
+        ] {
+            let decoded = DecodedRecord::try_decode(&nsid("sh.tangled.repo.pull"), json)
+                .expect("partial pull must scrub-recover");
+            assert!(matches!(decoded, DecodedRecord::Canon(Record::Pull(_))));
+        }
+    }
+
     #[test]
     fn try_decode_recovers_label_op_with_null_delete() {
         let json = br#"{"$type":"sh.tangled.label.op","add":[{"key":"at://did:plc:limpet/sh.tangled.label.definition/k","value":"v"}],"delete":null,"performedAt":"2026-05-01T00:00:00Z","subject":"at://did:plc:limpet/sh.tangled.repo.issue/3aaa"}"#;
-- 
2.51.2