Use non pointer mutex for lobby

We get a warning when trying to copy the lobby anyway. And this way we
don't have to manually initialise it.

Author: Bios-Marcel

internal/game/data.go

@@ -87,7 +87,7 @@ type Lobby struct {
 	// it is empty.
 	LastPlayerDisconnectTime *time.Time
 
-	mutex *sync.Mutex
+	mutex sync.Mutex
 
 	WriteObject          func(*Player, easyjson.Marshaler) error
 	WritePreparedMessage func(*Player, *gws.Broadcaster) error

internal/game/data_test.go

@@ -1,17 +1,14 @@
 package game
 
 import (
-	"sync"
 	"testing"
 	"time"
 )
 
 func TestOccupiedPlayerCount(t *testing.T) {
 	t.Parallel()
 
-	lobby := &Lobby{
-		mutex: &sync.Mutex{},
-	}
+	lobby := &Lobby{}
 	if lobby.GetOccupiedPlayerSlots() != 0 {
 		t.Errorf("Occupied player count expected to be 0, but was %d", lobby.GetOccupiedPlayerSlots())
 	}

internal/game/lobby.go

@@ -8,7 +8,6 @@ import (
 	"math/rand/v2"
 	"sort"
 	"strings"
-	"sync"
 	"time"
 	"unicode/utf8"
 
@@ -988,7 +987,6 @@ func CreateLobby(
 		CustomWords:    customWords,
 		currentDrawing: make([]any, 0),
 		State:          Unstarted,
-		mutex:          &sync.Mutex{},
 	}
 
 	if len(customWords) > 1 {

internal/game/lobby_test.go

@@ -3,7 +3,6 @@ package game
 import (
 	"encoding/json"
 	"reflect"
-	"sync"
 	"testing"
 	"unsafe"
 
@@ -19,7 +18,6 @@ func createLobbyWithDemoPlayers(playercount int) *Lobby {
 	lobby := &Lobby{
 		Owner:   owner,
 		creator: owner,
-		mutex:   &sync.Mutex{},
 	}
 	for i := 0; i < playercount; i++ {
 		lobby.players = append(lobby.players, &Player{
@@ -38,6 +36,16 @@ func noOpWritePreparedMessage(_ *Player, _ *gws.Broadcaster) error {
 	return nil
 }
 
+func Test_Locking(t *testing.T) {
+	t.Parallel()
+
+	lobby := &Lobby{}
+	lobby.mutex.Lock()
+	if lobby.mutex.TryLock() {
+		t.Error("Mutex shouldn't be aqcuiredable at this point")
+	}
+}
+
 func Test_CalculateVotesNeededToKick(t *testing.T) {
 	t.Parallel()
 
@@ -138,9 +146,7 @@ func Test_simplifyText(t *testing.T) {
 func Test_recalculateRanks(t *testing.T) {
 	t.Parallel()
 
-	lobby := &Lobby{
-		mutex: &sync.Mutex{},
-	}
+	lobby := &Lobby{}
 	lobby.players = append(lobby.players, &Player{
 		ID:        uuid.Must(uuid.NewV4()),
 		Score:     1,
@@ -228,7 +234,6 @@ func Test_wordSelectionEvent(t *testing.T) {
 	t.Parallel()
 
 	lobby := &Lobby{
-		mutex: &sync.Mutex{},
 		EditableLobbySettings: EditableLobbySettings{
 			DrawingTime: 10,
 			Rounds:      10,
@@ -326,7 +331,6 @@ func Test_kickDrawer(t *testing.T) {
 	t.Parallel()
 
 	lobby := &Lobby{
-		mutex: &sync.Mutex{},
 		EditableLobbySettings: EditableLobbySettings{
 			DrawingTime: 10,
 			Rounds:      10,

internal/game/words_test.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"fmt"
 	"strings"
-	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -90,7 +89,6 @@ func Test_getRandomWords(t *testing.T) {
 				CustomWordsPerTurn: 0,
 			},
 			words: []string{"a", "b", "c"},
-			mutex: &sync.Mutex{},
 		}
 
 		randomWords := GetRandomWords(3, lobby)
@@ -112,7 +110,6 @@ func Test_getRandomWords(t *testing.T) {
 			},
 
 			CustomWords: []string{"d", "e", "f"},
-			mutex:       &sync.Mutex{},
 		}
 
 		randomWords := GetRandomWords(3, lobby)
@@ -133,7 +130,6 @@ func Test_getRandomWords(t *testing.T) {
 				CustomWordsPerTurn: 3,
 			},
 			CustomWords: nil,
-			mutex:       &sync.Mutex{},
 		}
 
 		randomWords := GetRandomWords(3, lobby)
@@ -154,7 +150,6 @@ func Test_getRandomWords(t *testing.T) {
 				CustomWordsPerTurn: 3,
 			},
 			CustomWords: []string{"d", "e", "f"},
-			mutex:       &sync.Mutex{},
 		}
 
 		randomWords := GetRandomWords(3, lobby)
@@ -182,7 +177,6 @@ func Test_getRandomWordsReloading(t *testing.T) {
 				CustomWordsPerTurn: 0,
 			},
 			CustomWords: nil,
-			mutex:       &sync.Mutex{},
 		}
 
 		// Running this 10 times, expecting it to get 3 words each time, even
@@ -204,7 +198,6 @@ func Test_getRandomWordsReloading(t *testing.T) {
 				CustomWordsPerTurn: 3,
 			},
 			CustomWords: nil,
-			mutex:       &sync.Mutex{},
 		}
 
 		// Running this 10 times, expecting it to get 3 words each time, even
@@ -226,7 +219,6 @@ func Test_getRandomWordsReloading(t *testing.T) {
 				CustomWordsPerTurn: 3,
 			},
 			CustomWords: []string{"a"},
-			mutex:       &sync.Mutex{},
 		}
 
 		// Running this 10 times, expecting it to get 3 words each time, even