Clarify the use of gooseMutex to proect goose internal state

Signed-off-by: Brian Meek <brian@hntlabs.com>

internal/sqlutil/migrate.go

@@ -48,9 +48,11 @@ type Migration struct {
 	Down func(ctx context.Context, txn *sql.Tx) error
 }
 
+// Gaurs the internal state of Goose from being modified by concurrent tests or goroutines
+var gooseMutex sync.Mutex
+
 // Migrator
 type Migrator struct {
-	gooseMutex      sync.Mutex
 	db              *sql.DB
 	migrations      []Migration
 	knownMigrations map[string]struct{}
@@ -82,8 +84,8 @@ func (m *Migrator) AddMigrations(migrations ...Migration) {
 
 // Up executes all migrations in order they were added.
 func (m *Migrator) Up(ctx context.Context) error {
-	m.gooseMutex.Lock()
+	gooseMutex.Lock()
-	defer m.gooseMutex.Unlock()
+	defer gooseMutex.Unlock()
 	var (
 		err             error
 		dendriteVersion = internal.VersionString()

syncapi/sync/requestpool_test.go

@@ -128,19 +128,15 @@ func TestRequestPool_updatePresence(t *testing.T) {
 	go rp.cleanPresence(db, time.Millisecond*50)
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			beforeCount := func() int {
+			publisher.lock.Lock()
-				publisher.lock.Lock()
+			beforeCount := publisher.count
-				defer publisher.lock.Unlock()
+			publisher.lock.Unlock()
-				return publisher.count
-			}()
 			rp.updatePresence(db, tt.args.presence, tt.args.userID)
-			func() {
+			publisher.lock.Lock()
-				publisher.lock.Lock()
+			if tt.wantIncrease && publisher.count <= beforeCount {
-				defer publisher.lock.Unlock()
+				t.Fatalf("expected count to increase: %d <= %d", publisher.count, beforeCount)
-				if tt.wantIncrease && publisher.count <= beforeCount {
+			}
-					t.Fatalf("expected count to increase: %d <= %d", publisher.count, beforeCount)
+			publisher.lock.Unlock()
-				}
-			}()
 			time.Sleep(tt.args.sleep)
 		})
 	}