Fix race in memory topo

Signed-off-by: Rohit Nayak <[email protected]>
vitessio · Jul 20, 2023 · 731c889 · 731c889
1 parent 7e58261
commit 731c889
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Showing 3 changed files with 14 additions and 1 deletion.
diff --git a/go/vt/topo/memorytopo/election.go b/go/vt/topo/memorytopo/election.go
@@ -153,8 +153,12 @@ func (mp *cLeaderParticipation) WaitForNewLeader(ctx context.Context) (<-chan st
 	}
 
 	notifications := make(chan string, 8)
+
+	nextWatchIndexMu.Lock()
 	watchIndex := nextWatchIndex
 	nextWatchIndex++
+	nextWatchIndexMu.Unlock()
+
 	n.watches[watchIndex] = watch{lock: notifications}
 
 	if n.lock != nil {

diff --git a/go/vt/topo/memorytopo/memorytopo.go b/go/vt/topo/memorytopo/memorytopo.go
@@ -50,7 +50,8 @@ const (
 )
 
 var (
-	nextWatchIndex = 0
+	nextWatchIndex   = 0
+	nextWatchIndexMu sync.Mutex
 )
 
 // Factory is a memory-based implementation of topo.Factory.  It

diff --git a/go/vt/topo/memorytopo/watch.go b/go/vt/topo/memorytopo/watch.go
@@ -50,8 +50,12 @@ func (c *Conn) Watch(ctx context.Context, filePath string) (*topo.WatchData, <-c
 	}
 
 	notifications := make(chan *topo.WatchData, 100)
+
+	nextWatchIndexMu.Lock()
 	watchIndex := nextWatchIndex
 	nextWatchIndex++
+	nextWatchIndexMu.Unlock()
+
 	n.watches[watchIndex] = watch{contents: notifications}
 
 	go func() {
@@ -105,8 +109,12 @@ func (c *Conn) WatchRecursive(ctx context.Context, dirpath string) ([]*topo.Watc
 	})
 
 	notifications := make(chan *topo.WatchDataRecursive, 100)
+
+	nextWatchIndexMu.Lock()
 	watchIndex := nextWatchIndex
 	nextWatchIndex++
+	nextWatchIndexMu.Unlock()
+
 	n.watches[watchIndex] = watch{recursive: notifications}
 
 	go func() {