From 0be76e0b55de9deb7346919eb4c761ae7f4cc4c6 Mon Sep 17 00:00:00 2001
From: Tobias Klauser <tobias@cilium.io>
Date: Thu, 11 Jun 2026 14:28:32 +0200
Subject: [PATCH] statedb: avoid revision bumps for missing deletes

Currently, (*writeTxnState).delete increments the table revision before
checking whether the target object even exists. A committed delete of a
missing object could thus advance the table revision without producing a
corresponding revision index entry or watch notification.

Fix this by moving the revision allocation until after the primary key
lookup succeeded and any CompareAndDelete guard passed.

Signed-off-by: Tobias Klauser <tobias@cilium.io>
---
 db_test.go   | 21 +++++++++++++++++++++
 write_txn.go |  9 ++++-----
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/db_test.go b/db_test.go
index 1c9b205..b818803 100644
--- a/db_test.go
+++ b/db_test.go
@@ -835,6 +835,27 @@ func TestDB_Revision(t *testing.T) {
 	require.Equal(t, writeRevision, startRevision+1, "revision incremented on Insert")
 	readRevision = table.Revision(db.ReadTxn())
 	require.Equal(t, writeRevision, readRevision, "committed transaction changed revision")
+
+	// Committed no-op deletes do not increment the revision.
+	txn = db.WriteTxn(table)
+	_, hadOld, err := table.Delete(txn, &testObject{ID: 2})
+	require.NoError(t, err)
+	require.False(t, hadOld)
+	writeRevision = table.Revision(txn)
+	txn.Commit()
+	require.Equal(t, readRevision, writeRevision, "missing Delete did not increment revision")
+	readRevision = table.Revision(db.ReadTxn())
+	require.Equal(t, readRevision, readRevision, "committed missing Delete did not change revision")
+
+	// Committed deletes of existing objects increment the revision.
+	txn = db.WriteTxn(table)
+	_, hadOld, err = table.Delete(txn, &testObject{ID: 1})
+	require.NoError(t, err)
+	require.True(t, hadOld)
+	writeRevision = table.Revision(txn)
+	txn.Commit()
+	require.Equal(t, readRevision+1, writeRevision, "revision incremented on Delete")
+	require.Equal(t, writeRevision, table.Revision(db.ReadTxn()), "committed found Delete changed revision")
 }
 
 func TestDB_GetList(t *testing.T) {
diff --git a/write_txn.go b/write_txn.go
index cd87d9c..9730bcc 100644
--- a/write_txn.go
+++ b/write_txn.go
@@ -235,15 +235,12 @@ func (txn *writeTxnState) delete(meta TableMeta, guardRevision Revision, data an
 		return object{}, false, ErrTransactionClosed
 	}
 
-	// Look up table and allocate a new revision.
+	// Look up table.
 	tableName := meta.Name()
 	table := txn.tableEntries[meta.tablePos()]
 	if !table.locked {
 		return object{}, false, tableError(tableName, ErrTableNotLockedForWriting)
 	}
-	oldRevision := table.revision
-	table.revision++
-	revision := table.revision
 
 	// Delete from the primary index first to grab the object.
 	// We assume that "data" has only enough defined fields to
@@ -260,11 +257,13 @@ func (txn *writeTxnState) delete(meta TableMeta, guardRevision Revision, data an
 	if guardRevision > 0 {
 		if obj.revision != guardRevision {
 			idIndex.insert(idKey, obj)
-			table.revision = oldRevision
 			return obj, true, ErrRevisionNotEqual
 		}
 	}
 
+	table.revision++
+	revision := table.revision
+
 	// Remove the object from the revision index.
 	binary.BigEndian.PutUint64(txn.revKey[:], obj.revision)
 	txn.mustIndexWriteTxn(meta, RevisionIndexPos).delete(txn.revKey[:])