From 95cea1434d44a03fa960a112ef642f6df369b57e Mon Sep 17 00:00:00 2001
From: Seongmin Lee <git@boltless.me>
Date: Mon, 7 Sep 2026 20:06:15 +0900
Subject: [PATCH] knotmirror: fallback to repoDid as push actor

Signed-off-by: Seongmin Lee <git@boltless.me>
---
 knotfeed/legacy.go      |  9 +++++++--
 knotfeed/legacy_test.go | 16 ++++++++++++++--
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/knotfeed/legacy.go b/knotfeed/legacy.go
index e437c824c..5ca01a501 100644
--- a/knotfeed/legacy.go
+++ b/knotfeed/legacy.go
@@ -42,7 +42,7 @@ type legacyRefUpdate struct {
 	Ref          string     `json:"ref"`
 	OldSha       string     `json:"oldSha"`
 	NewSha       string     `json:"newSha"`
-	CommitterDid syntax.DID `json:"committerDid"`
+	CommitterDid string     `json:"committerDid"`
 	PushOptions  []string   `json:"pushOptions"`
 }
 
@@ -92,9 +92,14 @@ func legacyRefOp(payload json.RawMessage, commit *Commit) error {
 		Prior:      ParsePriorSha(event.OldSha),
 	}
 	if !newSha.IsZero() {
+		// old knots leave committerDid empty; attribute those pushes to the repo itself
+		editor, err := syntax.ParseDID(event.CommitterDid)
+		if err != nil {
+			editor = event.Repo
+		}
 		record, err := encodeRefRecord(RefRecord{
 			Sha:         newSha,
-			Editor:      event.CommitterDid,
+			Editor:      editor,
 			PushOptions: event.PushOptions,
 		})
 		if err != nil {
diff --git a/knotfeed/legacy_test.go b/knotfeed/legacy_test.go
index f8fca9f9e..e81720ddc 100644
--- a/knotfeed/legacy_test.go
+++ b/knotfeed/legacy_test.go
@@ -118,7 +118,7 @@ func TestLegacyFrameReadsAsCommit(t *testing.T) {
 				Repo: "did:plc:scallop",
 				Seq:  11,
 				Records: []RecordOp{refOp(t, "refs/heads/new", zeroSha1,
-					RefRecord{Sha: sha(t, legacyNewSha)})},
+					RefRecord{Sha: sha(t, legacyNewSha), Editor: "did:plc:scallop"})},
 			},
 		},
 		{
@@ -128,7 +128,19 @@ func TestLegacyFrameReadsAsCommit(t *testing.T) {
 				Repo: "did:plc:scallop",
 				Seq:  11,
 				Records: []RecordOp{refOp(t, "refs/heads/new", "",
-					RefRecord{Sha: sha(t, legacyNewSha)})},
+					RefRecord{Sha: sha(t, legacyNewSha), Editor: "did:plc:scallop"})},
+			},
+		},
+		{
+			name: "push with an empty committerDid",
+			frame: `{"nsid":"sh.tangled.git.refUpdate","created":11,` +
+				`"event":{"ref":"refs/heads/main","repo":"did:plc:scallop","committerDid":"",` +
+				`"oldSha":"` + legacyOldSha + `","newSha":"` + legacyNewSha + `"}}`,
+			want: Commit{
+				Repo: "did:plc:scallop",
+				Seq:  11,
+				Records: []RecordOp{refOp(t, "refs/heads/main", legacyOldSha,
+					RefRecord{Sha: sha(t, legacyNewSha), Editor: "did:plc:scallop"})},
 			},
 		},
 		{
-- 
2.51.2