catalog/lease: fix race condition with testing knob

Previously, the testing knob TestingDisableRangeFeedCheckpoint was read
without any mutex, which could lead to a race condition in certain tests
as detected by the race detector. To address this, this patch moves the
field into the lease manager as an atomic, since testing knobs are
copied, so they cannot store mutexes or atomics.

Fixes: #156182

Release note: None

Author: fqazi

pkg/sql/catalog/lease/lease.go

@@ -1567,6 +1567,11 @@ type Manager struct {
 	bytesMonitor *mon.BytesMonitor
 	// boundAccount tracks the memory usage from leased descriptors.
 	boundAccount *mon.ConcurrentBoundAccount
+
+	// TestingDisableRangeFeedCheckpoint is used to disable rangefeed checkpoints.
+	// Ideally, this would be inside StorageTestingKnobs, but those get copied into
+	// the lease manager.
+	TestingDisableRangeFeedCheckpoint atomic.Bool
 }
 
 const leaseConcurrencyLimit = 5
@@ -2506,7 +2511,7 @@ func (m *Manager) watchForUpdates(ctx context.Context) {
 		ctx context.Context, ev *kvpb.RangeFeedValue,
 	) {
 		// Skip updates if rangefeeds are disabled.
-		if m.testingKnobs.DisableRangeFeedCheckpoint {
+		if m.TestingDisableRangeFeedCheckpoint.Load() {
 			return
 		}
 		// Check first if it is the special descriptor metadata key used to track
@@ -2572,7 +2577,7 @@ func (m *Manager) watchForUpdates(ctx context.Context) {
 	}
 
 	handleCheckpoint := func(ctx context.Context, checkpoint *kvpb.RangeFeedCheckpoint) {
-		if m.testingKnobs.DisableRangeFeedCheckpoint {
+		if m.TestingDisableRangeFeedCheckpoint.Load() {
 			return
 		}
 		// Track checkpoints that occur from the rangefeed to make sure progress
@@ -3150,7 +3155,7 @@ func (m *Manager) TestingSetDisableRangeFeedCheckpointFn(disable bool) chan stru
 	m.mu.Lock()
 	defer m.mu.Unlock()
 	m.mu.rangeFeedCheckpoints = 0
-	m.testingKnobs.DisableRangeFeedCheckpoint = disable
+	m.TestingDisableRangeFeedCheckpoint.Store(disable)
 	if disable {
 		m.testingKnobs.RangeFeedResetChannel = make(chan struct{})
 	} else {

pkg/sql/catalog/lease/testutils.go

@@ -61,9 +61,6 @@ type ManagerTestingKnobs struct {
 	// To disable the deletion of orphaned leases at server startup.
 	DisableDeleteOrphanedLeases bool
 
-	// DisableRangeFeedCheckpoint is used to disable rangefeed checkpoints.
-	DisableRangeFeedCheckpoint bool
-
 	// RangeFeedReset channel is closed to indicate that the range feed
 	// has been reset.
 	RangeFeedResetChannel chan struct{}