Refactor Docker and Makefile configurations for improved build processes

- Updated docker-compose.tools.yml to mount source code at /src and set working directory for backend tools, ensuring proper Go module caching.
- Modified Dockerfile.tools to install the latest golangci-lint version compatible with Go 1.24 and adjusted working directory for build-time operations.
- Enhanced Makefile to build backend tools before running tests and linting, ensuring dependencies are up-to-date and improving overall workflow efficiency.
- Refactored test and handler files to include error handling for database operations, enhancing reliability and debugging capabilities.

internal/app/handlers/client.go

@@ -66,7 +66,7 @@ func (h *Handlers) clientLocate(rw http.ResponseWriter, req *http.Request) {
 	}
 	rw.Header().Set("Content-Type", "text/plain")
 	rw.WriteHeader(http.StatusOK)
-	rw.Write([]byte(result))
+	_, _ = rw.Write([]byte(result))
 }
 
 func (h *Handlers) clientGridUpdate(rw http.ResponseWriter, req *http.Request) {
@@ -85,7 +85,7 @@ func (h *Handlers) clientGridUpdate(rw http.ResponseWriter, req *http.Request) {
 	}
 	rw.Header().Set("Content-Type", "application/json")
 	rw.WriteHeader(http.StatusOK)
-	json.NewEncoder(rw).Encode(result.Response)
+	_ = json.NewEncoder(rw).Encode(result.Response)
 }
 
 func (h *Handlers) clientGridUpload(rw http.ResponseWriter, req *http.Request) {

internal/app/handlers/handlers_test.go

@@ -64,9 +64,11 @@ func (env *testEnv) createUser(t *testing.T, username, password string, auths ap
 	hash, _ := bcrypt.GenerateFromPassword([]byte(password), bcrypt.MinCost)
 	u := app.User{Pass: hash, Auths: auths}
 	raw, _ := json.Marshal(u)
-	env.st.Update(context.Background(), func(tx *bbolt.Tx) error {
+	if err := env.st.Update(context.Background(), func(tx *bbolt.Tx) error {
 		return env.st.PutUser(tx, username, raw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func (env *testEnv) loginSession(t *testing.T, username string) string {
@@ -90,7 +92,7 @@ func TestAPISetup_NoUsers(t *testing.T) {
 	}
 
 	var resp struct{ SetupRequired bool }
-	json.NewDecoder(rr.Body).Decode(&resp)
+	_ = json.NewDecoder(rr.Body).Decode(&resp)
 	if !resp.SetupRequired {
 		t.Fatal("expected setupRequired=true")
 	}
@@ -105,7 +107,7 @@ func TestAPISetup_WithUsers(t *testing.T) {
 	env.h.APISetup(rr, req)
 
 	var resp struct{ SetupRequired bool }
-	json.NewDecoder(rr.Body).Decode(&resp)
+	_ = json.NewDecoder(rr.Body).Decode(&resp)
 	if resp.SetupRequired {
 		t.Fatal("expected setupRequired=false with users")
 	}
@@ -196,7 +198,7 @@ func TestAPIMe_Authenticated(t *testing.T) {
 		Username string   `json:"username"`
 		Auths    []string `json:"auths"`
 	}
-	json.NewDecoder(rr.Body).Decode(&resp)
+	_ = json.NewDecoder(rr.Body).Decode(&resp)
 	if resp.Username != "alice" {
 		t.Fatalf("expected alice, got %s", resp.Username)
 	}
@@ -245,7 +247,7 @@ func TestAPIMeTokens_Authenticated(t *testing.T) {
 		t.Fatalf("expected 200, got %d: %s", rr.Code, rr.Body.String())
 	}
 	var resp struct{ Tokens []string }
-	json.NewDecoder(rr.Body).Decode(&resp)
+	_ = json.NewDecoder(rr.Body).Decode(&resp)
 	if len(resp.Tokens) != 1 {
 		t.Fatalf("expected 1 token, got %d", len(resp.Tokens))
 	}
@@ -396,7 +398,7 @@ func TestAdminSettings(t *testing.T) {
 		DefaultHide bool   `json:"defaultHide"`
 		Title       string `json:"title"`
 	}
-	json.NewDecoder(rr3.Body).Decode(&resp)
+	_ = json.NewDecoder(rr3.Body).Decode(&resp)
 	if resp.Prefix != "pfx" || !resp.DefaultHide || resp.Title != "New Title" {
 		t.Fatalf("unexpected settings: %+v", resp)
 	}
@@ -493,7 +495,7 @@ func TestAPIGetChars_NoMarkersAuth(t *testing.T) {
 		t.Fatalf("expected 200, got %d", rr.Code)
 	}
 	var chars []interface{}
-	json.NewDecoder(rr.Body).Decode(&chars)
+	_ = json.NewDecoder(rr.Body).Decode(&chars)
 	if len(chars) != 0 {
 		t.Fatal("expected empty array without markers auth")
 	}
@@ -511,7 +513,7 @@ func TestAPIGetMarkers_NoMarkersAuth(t *testing.T) {
 		t.Fatalf("expected 200, got %d", rr.Code)
 	}
 	var markers []interface{}
-	json.NewDecoder(rr.Body).Decode(&markers)
+	_ = json.NewDecoder(rr.Body).Decode(&markers)
 	if len(markers) != 0 {
 		t.Fatal("expected empty array without markers auth")
 	}
@@ -583,7 +585,7 @@ func TestAdminUserByName(t *testing.T) {
 		Username string   `json:"username"`
 		Auths    []string `json:"auths"`
 	}
-	json.NewDecoder(rr.Body).Decode(&resp)
+	_ = json.NewDecoder(rr.Body).Decode(&resp)
 	if resp.Username != "bob" {
 		t.Fatalf("expected bob, got %s", resp.Username)
 	}
@@ -613,9 +615,11 @@ func TestClientRouter_Locate(t *testing.T) {
 	}
 	gd := app.GridData{ID: "g1", Map: 1, Coord: app.Coord{X: 2, Y: 3}}
 	raw, _ := json.Marshal(gd)
-	env.st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := env.st.Update(ctx, func(tx *bbolt.Tx) error {
 		return env.st.PutGrid(tx, "g1", raw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	req := httptest.NewRequest(http.MethodGet, "/client/"+tokens[0]+"/locate?gridID=g1", nil)
 	rr := httptest.NewRecorder()

internal/app/handlers/tile.go

@@ -55,7 +55,7 @@ func (h *Handlers) WatchGridUpdates(rw http.ResponseWriter, req *http.Request) {
 	tileCache := []services.TileCache{}
 	raw, _ := json.Marshal(tileCache)
 	fmt.Fprint(rw, "data: ")
-	rw.Write(raw)
+	_, _ = rw.Write(raw)
 	fmt.Fprint(rw, "\n\n")
 	flusher.Flush()
 
@@ -93,13 +93,13 @@ func (h *Handlers) WatchGridUpdates(rw http.ResponseWriter, req *http.Request) {
 			}
 			fmt.Fprint(rw, "event: merge\n")
 			fmt.Fprint(rw, "data: ")
-			rw.Write(raw)
+			_, _ = rw.Write(raw)
 			fmt.Fprint(rw, "\n\n")
 			flusher.Flush()
 		case <-ticker.C:
 			raw, _ := json.Marshal(tileCache)
 			fmt.Fprint(rw, "data: ")
-			rw.Write(raw)
+			_, _ = rw.Write(raw)
 			fmt.Fprint(rw, "\n\n")
 			tileCache = tileCache[:0]
 			flusher.Flush()
@@ -152,7 +152,7 @@ func (h *Handlers) GridTile(rw http.ResponseWriter, req *http.Request) {
 		rw.Header().Set("Content-Type", "image/png")
 		rw.Header().Set("Cache-Control", "private, max-age=3600")
 		rw.WriteHeader(http.StatusOK)
-		rw.Write(transparentPNG)
+		_, _ = rw.Write(transparentPNG)
 		return
 	}
 

internal/app/migrations.go

@@ -172,7 +172,9 @@ var migrations = []func(tx *bbolt.Tx) error{
 				if err != nil {
 					return err
 				}
-				users.Put(k, raw)
+				if err := users.Put(k, raw); err != nil {
+					return err
+				}
 			}
 			return nil
 		})

internal/app/migrations_test.go

@@ -26,7 +26,7 @@ func TestRunMigrations_FreshDB(t *testing.T) {
 		t.Fatalf("migrations failed on fresh DB: %v", err)
 	}
 
-	db.View(func(tx *bbolt.Tx) error {
+	if err := db.View(func(tx *bbolt.Tx) error {
 		b := tx.Bucket(store.BucketConfig)
 		if b == nil {
 			t.Fatal("expected config bucket after migrations")
@@ -40,13 +40,15 @@ func TestRunMigrations_FreshDB(t *testing.T) {
 			t.Fatalf("expected default title, got %s", title)
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	if tx, _ := db.Begin(false); tx != nil {
 		if tx.Bucket(store.BucketOAuthStates) == nil {
 			t.Fatal("expected oauth_states bucket after migrations")
 		}
-		tx.Rollback()
+		_ = tx.Rollback()
 	}
 }
 
@@ -61,7 +63,7 @@ func TestRunMigrations_Idempotent(t *testing.T) {
 		t.Fatalf("second run failed: %v", err)
 	}
 
-	db.View(func(tx *bbolt.Tx) error {
+	if err := db.View(func(tx *bbolt.Tx) error {
 		b := tx.Bucket(store.BucketConfig)
 		if b == nil {
 			t.Fatal("expected config bucket")
@@ -71,7 +73,9 @@ func TestRunMigrations_Idempotent(t *testing.T) {
 			t.Fatal("expected version key")
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestRunMigrations_SetsVersion(t *testing.T) {
@@ -81,11 +85,13 @@ func TestRunMigrations_SetsVersion(t *testing.T) {
 	}
 
 	var version string
-	db.View(func(tx *bbolt.Tx) error {
+	if err := db.View(func(tx *bbolt.Tx) error {
 		b := tx.Bucket(store.BucketConfig)
 		version = string(b.Get([]byte("version")))
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	if version == "" || version == "0" {
 		t.Fatalf("expected non-zero version, got %q", version)

internal/app/services/admin.go

@@ -101,7 +101,9 @@ func (s *AdminService) DeleteUser(ctx context.Context, username string) error {
 				return err
 			}
 			for _, tok := range u.Tokens {
-				s.st.DeleteToken(tx, tok)
+				if err := s.st.DeleteToken(tx, tok); err != nil {
+					return err
+				}
 			}
 		}
 		return s.st.DeleteUser(tx, username)
@@ -129,17 +131,25 @@ func (s *AdminService) GetSettings(ctx context.Context) (prefix string, defaultH
 func (s *AdminService) UpdateSettings(ctx context.Context, prefix *string, defaultHide *bool, title *string) error {
 	return s.st.Update(ctx, func(tx *bbolt.Tx) error {
 		if prefix != nil {
-			s.st.PutConfig(tx, "prefix", []byte(*prefix))
+			if err := s.st.PutConfig(tx, "prefix", []byte(*prefix)); err != nil {
+				return err
+			}
 		}
 		if defaultHide != nil {
 			if *defaultHide {
-				s.st.PutConfig(tx, "defaultHide", []byte("1"))
+				if err := s.st.PutConfig(tx, "defaultHide", []byte("1")); err != nil {
+					return err
+				}
 			} else {
-				s.st.DeleteConfig(tx, "defaultHide")
+				if err := s.st.DeleteConfig(tx, "defaultHide"); err != nil {
+					return err
+				}
 			}
 		}
 		if title != nil {
-			s.st.PutConfig(tx, "title", []byte(*title))
+			if err := s.st.PutConfig(tx, "title", []byte(*title)); err != nil {
+				return err
+			}
 		}
 		return nil
 	})
@@ -264,7 +274,9 @@ func (s *AdminService) WipeTile(ctx context.Context, mapid, x, y int) error {
 			return err
 		}
 		for _, id := range ids {
-			grids.Delete(id)
+			if err := grids.Delete(id); err != nil {
+				return err
+			}
 		}
 		return nil
 	}); err != nil {
@@ -310,7 +322,9 @@ func (s *AdminService) SetCoords(ctx context.Context, mapid, fx, fy, tx2, ty int
 				g.Coord.X += diff.X
 				g.Coord.Y += diff.Y
 				raw, _ := json.Marshal(g)
-				grids.Put(k, raw)
+				if err := grids.Put(k, raw); err != nil {
+					return err
+				}
 			}
 			return nil
 		}); err != nil {
@@ -367,7 +381,9 @@ func (s *AdminService) HideMarker(ctx context.Context, markerID string) error {
 		}
 		m.Hidden = true
 		raw, _ = json.Marshal(m)
-		grid.Put(key, raw)
+		if err := grid.Put(key, raw); err != nil {
+			return err
+		}
 		return nil
 	})
 }

internal/app/services/admin_test.go

@@ -234,7 +234,7 @@ func TestToggleMapHidden(t *testing.T) {
 	admin, _ := newTestAdmin(t)
 	ctx := context.Background()
 
-	admin.UpdateMap(ctx, 1, "world", false, false)
+	_ = admin.UpdateMap(ctx, 1, "world", false, false)
 
 	mi, err := admin.ToggleMapHidden(ctx, 1)
 	if err != nil {
@@ -257,19 +257,27 @@ func TestWipe(t *testing.T) {
 	admin, st := newTestAdmin(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
-		st.PutGrid(tx, "g1", []byte("data"))
-		st.PutMap(tx, 1, []byte("data"))
-		st.PutTile(tx, 1, 0, "0_0", []byte("data"))
-		st.CreateMarkersBuckets(tx)
-		return nil
-	})
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
+		if err := st.PutGrid(tx, "g1", []byte("data")); err != nil {
+			return err
+		}
+		if err := st.PutMap(tx, 1, []byte("data")); err != nil {
+			return err
+		}
+		if err := st.PutTile(tx, 1, 0, "0_0", []byte("data")); err != nil {
+			return err
+		}
+		_, _, err := st.CreateMarkersBuckets(tx)
+		return err
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	if err := admin.Wipe(ctx); err != nil {
 		t.Fatal(err)
 	}
 
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		if st.GetGrid(tx, "g1") != nil {
 			t.Fatal("expected grids wiped")
 		}
@@ -283,7 +291,9 @@ func TestWipe(t *testing.T) {
 			t.Fatal("expected markers wiped")
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestGetMap_NotFound(t *testing.T) {

internal/app/services/auth.go

@@ -53,7 +53,7 @@ func (s *AuthService) GetSession(ctx context.Context, req *http.Request) *app.Se
 		return nil
 	}
 	var sess *app.Session
-	s.st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := s.st.View(ctx, func(tx *bbolt.Tx) error {
 		raw := s.st.GetSession(tx, c.Value)
 		if raw == nil {
 			return nil
@@ -77,7 +77,9 @@ func (s *AuthService) GetSession(ctx context.Context, req *http.Request) *app.Se
 		}
 		sess.Auths = u.Auths
 		return nil
-	})
+	}); err != nil {
+		return nil
+	}
 	return sess
 }
 
@@ -165,7 +167,7 @@ func (s *AuthService) GetUserByUsername(ctx context.Context, username string) *a
 // SetupRequired returns true if no users exist (first run).
 func (s *AuthService) SetupRequired(ctx context.Context) bool {
 	var required bool
-	s.st.View(ctx, func(tx *bbolt.Tx) error {
+	_ = s.st.View(ctx, func(tx *bbolt.Tx) error {
 		if s.st.UserCount(tx) == 0 {
 			required = true
 		}
@@ -181,7 +183,7 @@ func (s *AuthService) BootstrapAdmin(ctx context.Context, username, pass, bootst
 	}
 	var created bool
 	var u *app.User
-	s.st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := s.st.Update(ctx, func(tx *bbolt.Tx) error {
 		if s.st.GetUser(tx, "admin") != nil {
 			return nil
 		}
@@ -200,7 +202,9 @@ func (s *AuthService) BootstrapAdmin(ctx context.Context, username, pass, bootst
 		created = true
 		u = &user
 		return nil
-	})
+	}); err != nil {
+		return nil
+	}
 	if created {
 		return u
 	}
@@ -239,7 +243,7 @@ func (s *AuthService) GenerateTokenForUser(ctx context.Context, username string)
 	}
 	token := hex.EncodeToString(tokenRaw)
 	var tokens []string
-	s.st.Update(ctx, func(tx *bbolt.Tx) error {
+	_ = s.st.Update(ctx, func(tx *bbolt.Tx) error {
 		uRaw := s.st.GetUser(tx, username)
 		u := app.User{}
 		if uRaw != nil {
@@ -250,7 +254,9 @@ func (s *AuthService) GenerateTokenForUser(ctx context.Context, username string)
 		u.Tokens = append(u.Tokens, token)
 		tokens = u.Tokens
 		buf, _ := json.Marshal(u)
-		s.st.PutUser(tx, username, buf)
+		if err := s.st.PutUser(tx, username, buf); err != nil {
+			return err
+		}
 		return s.st.PutToken(tx, token, username)
 	})
 	return tokens
@@ -522,7 +528,9 @@ func (s *AuthService) findOrCreateOAuthUser(ctx context.Context, provider, sub,
 					user.Email = email
 				}
 				raw, _ = json.Marshal(user)
-				s.st.PutUser(tx, username, raw)
+				if err := s.st.PutUser(tx, username, raw); err != nil {
+					return err
+				}
 			}
 			return nil
 		}

internal/app/services/auth_test.go

@@ -41,9 +41,11 @@ func createUser(t *testing.T, st *store.Store, username, password string, auths
 	}
 	u := app.User{Pass: hash, Auths: auths}
 	raw, _ := json.Marshal(u)
-	st.Update(context.Background(), func(tx *bbolt.Tx) error {
+	if err := st.Update(context.Background(), func(tx *bbolt.Tx) error {
 		return st.PutUser(tx, username, raw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestSetupRequired_EmptyDB(t *testing.T) {
@@ -246,9 +248,11 @@ func TestGetUserTokensAndPrefix(t *testing.T) {
 	ctx := context.Background()
 	createUser(t, st, "alice", "pass", app.Auths{app.AUTH_UPLOAD})
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		return st.PutConfig(tx, "prefix", []byte("myprefix"))
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	auth.GenerateTokenForUser(ctx, "alice")
 	tokens, prefix := auth.GetUserTokensAndPrefix(ctx, "alice")
@@ -288,9 +292,11 @@ func TestValidateClientToken_NoUploadPerm(t *testing.T) {
 	ctx := context.Background()
 	createUser(t, st, "alice", "pass", app.Auths{app.AUTH_MAP})
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		return st.PutToken(tx, "tok123", "alice")
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	_, err := auth.ValidateClientToken(ctx, "tok123")
 	if err == nil {

internal/app/services/client.go

@@ -141,7 +141,9 @@ func (s *ClientService) ProcessGridUpdate(ctx context.Context, grup GridUpdate)
 					if err != nil {
 						return err
 					}
-					grids.Put([]byte(grid), raw)
+					if err := grids.Put([]byte(grid), raw); err != nil {
+						return err
+					}
 					greq.GridRequests = append(greq.GridRequests, grid)
 				}
 			}
@@ -192,7 +194,9 @@ func (s *ClientService) ProcessGridUpdate(ctx context.Context, grup GridUpdate)
 				if err != nil {
 					return err
 				}
-				grids.Put([]byte(grid), raw)
+				if err := grids.Put([]byte(grid), raw); err != nil {
+					return err
+				}
 				greq.GridRequests = append(greq.GridRequests, grid)
 			}
 		}
@@ -207,7 +211,7 @@ func (s *ClientService) ProcessGridUpdate(ctx context.Context, grup GridUpdate)
 			}
 		}
 		if len(maps) > 1 {
-			grids.ForEach(func(k, v []byte) error {
+			if err := grids.ForEach(func(k, v []byte) error {
 				gd := app.GridData{}
 				if err := json.Unmarshal(v, &gd); err != nil {
 					return err
@@ -244,16 +248,22 @@ func (s *ClientService) ProcessGridUpdate(ctx context.Context, grup GridUpdate)
 							File:  td.File,
 						})
 					}
-					grids.Put(k, raw)
+					if err := grids.Put(k, raw); err != nil {
+						return err
+					}
 				}
 				return nil
-			})
+			}); err != nil {
+				return err
+			}
 		}
 		for mergeid, merge := range maps {
 			if mapid == mergeid {
 				continue
 			}
-			mapB.Delete([]byte(strconv.Itoa(mergeid)))
+			if err := mapB.Delete([]byte(strconv.Itoa(mergeid))); err != nil {
+				return err
+			}
 			slog.Info("reporting merge", "from", mergeid, "to", mapid)
 			s.mapSvc.ReportMerge(mergeid, mapid, app.Coord{X: offset.X - merge.X, Y: offset.Y - merge.Y})
 		}
@@ -271,10 +281,10 @@ func (s *ClientService) ProcessGridUpdate(ctx context.Context, grup GridUpdate)
 func (s *ClientService) ProcessGridUpload(ctx context.Context, id string, extraData string, fileReader io.Reader) error {
 	if extraData != "" {
 		ed := ExtraData{}
-		json.Unmarshal([]byte(extraData), &ed)
+		_ = json.Unmarshal([]byte(extraData), &ed)
 		if ed.Season == 3 {
 			needTile := false
-			s.st.Update(ctx, func(tx *bbolt.Tx) error {
+			if err := s.st.Update(ctx, func(tx *bbolt.Tx) error {
 				raw := s.st.GetGrid(tx, id)
 				if raw == nil {
 					return fmt.Errorf("unknown grid id: %s", id)
@@ -301,7 +311,9 @@ func (s *ClientService) ProcessGridUpload(ctx context.Context, id string, extraD
 				}
 				raw, _ = json.Marshal(cur)
 				return s.st.PutGrid(tx, id, raw)
-			})
+			}); err != nil {
+				return err
+			}
 			if !needTile {
 				slog.Debug("ignoring tile upload: winter")
 				return nil
@@ -316,7 +328,7 @@ func (s *ClientService) ProcessGridUpload(ctx context.Context, id string, extraD
 	cur := app.GridData{}
 	mapid := 0
 
-	s.st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := s.st.Update(ctx, func(tx *bbolt.Tx) error {
 		raw := s.st.GetGrid(tx, id)
 		if raw == nil {
 			return fmt.Errorf("unknown grid id: %s", id)
@@ -331,7 +343,9 @@ func (s *ClientService) ProcessGridUpload(ctx context.Context, id string, extraD
 		}
 		raw, _ = json.Marshal(cur)
 		return s.st.PutGrid(tx, id, raw)
-	})
+	}); err != nil {
+		return err
+	}
 
 	if updateTile {
 		gridDir := fmt.Sprintf("%s/grids", s.mapSvc.GridStorage())
@@ -374,7 +388,7 @@ func (s *ClientService) UpdatePositions(ctx context.Context, data []byte) error
 	}
 
 	gridDataByID := make(map[string]app.GridData)
-	s.st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := s.st.View(ctx, func(tx *bbolt.Tx) error {
 		for _, craw := range craws {
 			raw := s.st.GetGrid(tx, craw.GridID)
 			if raw != nil {
@@ -385,7 +399,9 @@ func (s *ClientService) UpdatePositions(ctx context.Context, data []byte) error
 			}
 		}
 		return nil
-	})
+	}); err != nil {
+		return err
+	}
 
 	username, _ := ctx.Value(app.ClientUsernameKey).(string)
 
@@ -478,8 +494,12 @@ func (s *ClientService) UploadMarkers(ctx context.Context, data []byte) error {
 				Image:    img,
 			}
 			raw, _ := json.Marshal(m)
-			grid.Put(key, raw)
-			idB.Put(idKey, key)
+			if err := grid.Put(key, raw); err != nil {
+				return err
+			}
+			if err := idB.Put(idKey, key); err != nil {
+				return err
+			}
 		}
 		return nil
 	})

internal/app/services/client_test.go

@@ -58,9 +58,11 @@ func TestClientLocate_Found(t *testing.T) {
 	ctx := context.Background()
 	gd := app.GridData{ID: "g1", Map: 1, Coord: app.Coord{X: 2, Y: 3}}
 	raw, _ := json.Marshal(gd)
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		return st.PutGrid(tx, "g1", raw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 	result, err := client.Locate(ctx, "g1")
 	if err != nil {
 		t.Fatal(err)

internal/app/services/export.go

@@ -111,7 +111,7 @@ func (s *ExportService) Export(ctx context.Context, w io.Writer) error {
 		if markersb != nil {
 			markersgrid := markersb.Bucket(store.BucketMarkersGrid)
 			if markersgrid != nil {
-				markersgrid.ForEach(func(k, v []byte) error {
+				if err := markersgrid.ForEach(func(k, v []byte) error {
 					select {
 					case <-ctx.Done():
 						return ctx.Err()
@@ -125,7 +125,9 @@ func (s *ExportService) Export(ctx context.Context, w io.Writer) error {
 						maps[gridMap[marker.GridID]].Markers[marker.GridID] = append(maps[gridMap[marker.GridID]].Markers[marker.GridID], marker)
 					}
 					return nil
-				})
+				}); err != nil {
+					return err
+				}
 			}
 		}
 		return nil
@@ -218,7 +220,11 @@ func (s *ExportService) Merge(ctx context.Context, zr *zip.Reader) error {
 					f.Close()
 					return err
 				}
-				io.Copy(f, r)
+				if _, err := io.Copy(f, r); err != nil {
+					r.Close()
+					f.Close()
+					return err
+				}
 				r.Close()
 				f.Close()
 				newTiles[strings.TrimSuffix(filepath.Base(fhdr.Name), ".png")] = struct{}{}
@@ -290,8 +296,12 @@ func (s *ExportService) processMergeJSON(
 				Image:    img,
 			}
 			raw, _ := json.Marshal(m)
-			mgrid.Put(key, raw)
-			idB.Put(idKey, key)
+			if err := mgrid.Put(key, raw); err != nil {
+				return err
+			}
+			if err := idB.Put(idKey, key); err != nil {
+				return err
+			}
 		}
 	}
 
@@ -333,7 +343,9 @@ func (s *ExportService) processMergeJSON(
 			if err != nil {
 				return err
 			}
-			grids.Put([]byte(grid), raw)
+			if err := grids.Put([]byte(grid), raw); err != nil {
+				return err
+			}
 		}
 		return nil
 	}
@@ -372,11 +384,13 @@ func (s *ExportService) processMergeJSON(
 		if err != nil {
 			return err
 		}
-		grids.Put([]byte(grid), raw)
+		if err := grids.Put([]byte(grid), raw); err != nil {
+			return err
+		}
 	}
 
 	if len(existingMaps) > 1 {
-		grids.ForEach(func(k, v []byte) error {
+		if err := grids.ForEach(func(k, v []byte) error {
 			gd := app.GridData{}
 			if err := json.Unmarshal(v, &gd); err != nil {
 				return err
@@ -413,16 +427,22 @@ func (s *ExportService) processMergeJSON(
 						File:  td.File,
 					})
 				}
-				grids.Put(k, raw)
+				if err := grids.Put(k, raw); err != nil {
+					return err
+				}
 			}
 			return nil
-		})
+		}); err != nil {
+			return err
+		}
 	}
 	for mergeid, merge := range existingMaps {
 		if mapid == mergeid {
 			continue
 		}
-		mapB.Delete([]byte(strconv.Itoa(mergeid)))
+		if err := mapB.Delete([]byte(strconv.Itoa(mergeid))); err != nil {
+			return err
+		}
 		slog.Info("reporting merge", "from", mergeid, "to", mapid)
 		s.mapSvc.ReportMerge(mergeid, mapid, app.Coord{X: offset.X - merge.X, Y: offset.Y - merge.Y})
 	}

internal/app/services/export_test.go

@@ -47,12 +47,14 @@ func TestExport_WithGrid(t *testing.T) {
 	gdRaw, _ := json.Marshal(gd)
 	mi := app.MapInfo{ID: 1, Name: "test", Hidden: false}
 	miRaw, _ := json.Marshal(mi)
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		if err := st.PutGrid(tx, "g1", gdRaw); err != nil {
 			return err
 		}
 		return st.PutMap(tx, 1, miRaw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 	var buf bytes.Buffer
 	err := export.Export(ctx, &buf)
 	if err != nil {

internal/app/services/map.go

@@ -218,7 +218,7 @@ func (s *MapService) getSubTiles(ctx context.Context, mapid int, c app.Coord, z
 
 // SaveTile persists a tile and broadcasts the update.
 func (s *MapService) SaveTile(ctx context.Context, mapid int, c app.Coord, z int, f string, t int64) {
-	s.st.Update(ctx, func(tx *bbolt.Tx) error {
+	_ = s.st.Update(ctx, func(tx *bbolt.Tx) error {
 		td := &app.TileData{
 			MapID: mapid,
 			Coord: c,
@@ -293,7 +293,7 @@ func (s *MapService) RebuildZooms(ctx context.Context) error {
 		if b == nil {
 			return nil
 		}
-		b.ForEach(func(k, v []byte) error {
+		if err := b.ForEach(func(k, v []byte) error {
 			select {
 			case <-ctx.Done():
 				return ctx.Err()
@@ -306,8 +306,12 @@ func (s *MapService) RebuildZooms(ctx context.Context) error {
 			needProcess[zoomproc{grid.Coord.Parent(), grid.Map}] = struct{}{}
 			saveGrid[zoomproc{grid.Coord, grid.Map}] = grid.ID
 			return nil
-		})
-		tx.DeleteBucket(store.BucketTiles)
+		}); err != nil {
+			return err
+		}
+		if err := tx.DeleteBucket(store.BucketTiles); err != nil {
+			return err
+		}
 		return nil
 	}); err != nil {
 		slog.Error("RebuildZooms: failed to update store", "error", err)
@@ -364,7 +368,7 @@ func (s *MapService) WatchMerges() chan *app.Merge {
 // GetAllTileCache returns all tiles for the initial SSE cache dump.
 func (s *MapService) GetAllTileCache(ctx context.Context) []TileCache {
 	var cache []TileCache
-	s.st.View(ctx, func(tx *bbolt.Tx) error {
+	_ = s.st.View(ctx, func(tx *bbolt.Tx) error {
 		return s.st.ForEachTile(tx, func(mapK, zoomK, coordK, v []byte) error {
 			select {
 			case <-ctx.Done():

internal/app/services/map_test.go

@@ -57,9 +57,11 @@ func TestGetConfig(t *testing.T) {
 	svc, st := newTestMapService(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		return st.PutConfig(tx, "title", []byte("Test Map"))
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	config, err := svc.GetConfig(ctx, app.Auths{app.AUTH_MAP})
 	if err != nil {
@@ -93,9 +95,11 @@ func TestGetConfig_Empty(t *testing.T) {
 func TestGetPage(t *testing.T) {
 	svc, st := newTestMapService(t)
 	ctx := context.Background()
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		return st.PutConfig(tx, "title", []byte("Map Page"))
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	page, err := svc.GetPage(ctx)
 	if err != nil {
@@ -112,9 +116,11 @@ func TestGetGrid(t *testing.T) {
 
 	gd := app.GridData{ID: "g1", Map: 1, Coord: app.Coord{X: 5, Y: 10}}
 	raw, _ := json.Marshal(gd)
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		return st.PutGrid(tx, "g1", raw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	got, err := svc.GetGrid(ctx, "g1")
 	if err != nil {
@@ -158,11 +164,17 @@ func TestGetMaps_HiddenFilter(t *testing.T) {
 	mi2 := app.MapInfo{ID: 2, Name: "hidden", Hidden: true}
 	raw1, _ := json.Marshal(mi1)
 	raw2, _ := json.Marshal(mi2)
-	st.Update(ctx, func(tx *bbolt.Tx) error {
-		st.PutMap(tx, 1, raw1)
-		st.PutMap(tx, 2, raw2)
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
+		if err := st.PutMap(tx, 1, raw1); err != nil {
+			return err
+		}
+		if err := st.PutMap(tx, 2, raw2); err != nil {
+			return err
+		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	maps, err := svc.GetMaps(ctx, false)
 	if err != nil {
@@ -201,14 +213,18 @@ func TestGetMarkers_WithData(t *testing.T) {
 	m := app.Marker{Name: "Tower", ID: 1, GridID: "g1", Position: app.Position{X: 10, Y: 20}, Image: "gfx/terobjs/mm/tower"}
 	mRaw, _ := json.Marshal(m)
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
-		st.PutGrid(tx, "g1", gdRaw)
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
+		if err := st.PutGrid(tx, "g1", gdRaw); err != nil {
+			return err
+		}
 		grid, _, err := st.CreateMarkersBuckets(tx)
 		if err != nil {
 			return err
 		}
 		return grid.Put([]byte("g1_10_20"), mRaw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	markers, err := svc.GetMarkers(ctx)
 	if err != nil {
@@ -233,9 +249,11 @@ func TestGetTile(t *testing.T) {
 
 	td := app.TileData{MapID: 1, Coord: app.Coord{X: 0, Y: 0}, Zoom: 0, File: "grids/g1.png", Cache: 12345}
 	raw, _ := json.Marshal(td)
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		return st.PutTile(tx, 1, 0, "0_0", raw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	got := svc.GetTile(ctx, 1, app.Coord{X: 0, Y: 0}, 0)
 	if got == nil {
@@ -287,9 +305,11 @@ func TestGetAllTileCache_WithData(t *testing.T) {
 
 	td := app.TileData{MapID: 1, Coord: app.Coord{X: 1, Y: 2}, Zoom: 0, Cache: 999}
 	raw, _ := json.Marshal(td)
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		return st.PutTile(tx, 1, 0, "1_2", raw)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	cache := svc.GetAllTileCache(ctx)
 	if len(cache) != 1 {

internal/app/store/db_test.go

@@ -25,12 +25,14 @@ func TestUserCRUD(t *testing.T) {
 	ctx := context.Background()
 
 	// Verify user doesn't exist on empty DB.
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		if got := st.GetUser(tx, "alice"); got != nil {
 			t.Fatal("expected nil user before creation")
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	// Create user.
 	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
@@ -40,7 +42,7 @@ func TestUserCRUD(t *testing.T) {
 	}
 
 	// Verify user exists and count is correct (separate transaction for accurate Stats).
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		got := st.GetUser(tx, "alice")
 		if got == nil || string(got) != `{"pass":"hash"}` {
 			t.Fatalf("expected user data, got %s", got)
@@ -49,7 +51,9 @@ func TestUserCRUD(t *testing.T) {
 			t.Fatalf("expected 1 user, got %d", c)
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	// Delete user.
 	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
@@ -58,31 +62,41 @@ func TestUserCRUD(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		if got := st.GetUser(tx, "alice"); got != nil {
 			t.Fatal("expected nil user after deletion")
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestForEachUser(t *testing.T) {
 	st := newTestStore(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
-		st.PutUser(tx, "alice", []byte("1"))
-		st.PutUser(tx, "bob", []byte("2"))
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
+		if err := st.PutUser(tx, "alice", []byte("1")); err != nil {
+			return err
+		}
+		if err := st.PutUser(tx, "bob", []byte("2")); err != nil {
+			return err
+		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	var names []string
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		return st.ForEachUser(tx, func(k, _ []byte) error {
 			names = append(names, string(k))
 			return nil
 		})
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 	if len(names) != 2 {
 		t.Fatalf("expected 2 users, got %d", len(names))
 	}
@@ -91,12 +105,14 @@ func TestForEachUser(t *testing.T) {
 func TestUserCountEmptyBucket(t *testing.T) {
 	st := newTestStore(t)
 	ctx := context.Background()
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		if c := st.UserCount(tx); c != 0 {
 			t.Fatalf("expected 0 users on empty db, got %d", c)
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestSessionCRUD(t *testing.T) {
@@ -211,19 +227,27 @@ func TestForEachMap(t *testing.T) {
 	st := newTestStore(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
-		st.PutMap(tx, 1, []byte("a"))
-		st.PutMap(tx, 2, []byte("b"))
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
+		if err := st.PutMap(tx, 1, []byte("a")); err != nil {
+			return err
+		}
+		if err := st.PutMap(tx, 2, []byte("b")); err != nil {
+			return err
+		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	var count int
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		return st.ForEachMap(tx, func(_, _ []byte) error {
 			count++
 			return nil
 		})
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 	if count != 2 {
 		t.Fatalf("expected 2 maps, got %d", count)
 	}
@@ -290,20 +314,30 @@ func TestForEachTile(t *testing.T) {
 	st := newTestStore(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
-		st.PutTile(tx, 1, 0, "0_0", []byte("a"))
-		st.PutTile(tx, 1, 1, "0_0", []byte("b"))
-		st.PutTile(tx, 2, 0, "1_1", []byte("c"))
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
+		if err := st.PutTile(tx, 1, 0, "0_0", []byte("a")); err != nil {
+			return err
+		}
+		if err := st.PutTile(tx, 1, 1, "0_0", []byte("b")); err != nil {
+			return err
+		}
+		if err := st.PutTile(tx, 2, 0, "1_1", []byte("c")); err != nil {
+			return err
+		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
 	var count int
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		return st.ForEachTile(tx, func(_, _, _, _ []byte) error {
 			count++
 			return nil
 		})
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 	if count != 3 {
 		t.Fatalf("expected 3 tiles, got %d", count)
 	}
@@ -313,7 +347,7 @@ func TestTilesMapBucket(t *testing.T) {
 	st := newTestStore(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		if b := st.GetTilesMapBucket(tx, 1); b != nil {
 			t.Fatal("expected nil bucket before creation")
 		}
@@ -328,31 +362,39 @@ func TestTilesMapBucket(t *testing.T) {
 			t.Fatal("expected non-nil after create")
 		}
 		return st.DeleteTilesMapBucket(tx, 1)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestDeleteTilesBucket(t *testing.T) {
 	st := newTestStore(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
-		st.PutTile(tx, 1, 0, "0_0", []byte("a"))
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
+		if err := st.PutTile(tx, 1, 0, "0_0", []byte("a")); err != nil {
+			return err
+		}
 		return st.DeleteTilesBucket(tx)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		if got := st.GetTile(tx, 1, 0, "0_0"); got != nil {
 			t.Fatal("expected nil after bucket deletion")
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestMarkerBuckets(t *testing.T) {
 	st := newTestStore(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		if b := st.GetMarkersGridBucket(tx); b != nil {
 			t.Fatal("expected nil grid bucket before creation")
 		}
@@ -376,7 +418,9 @@ func TestMarkerBuckets(t *testing.T) {
 			t.Fatal("expected non-zero sequence")
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestOAuthStateCRUD(t *testing.T) {
@@ -408,23 +452,29 @@ func TestBucketExistsAndDelete(t *testing.T) {
 	st := newTestStore(t)
 	ctx := context.Background()
 
-	st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := st.Update(ctx, func(tx *bbolt.Tx) error {
 		if st.BucketExists(tx, store.BucketUsers) {
 			t.Fatal("expected bucket to not exist")
 		}
-		st.PutUser(tx, "alice", []byte("x"))
+		if err := st.PutUser(tx, "alice", []byte("x")); err != nil {
+			return err
+		}
 		if !st.BucketExists(tx, store.BucketUsers) {
 			t.Fatal("expected bucket to exist")
 		}
 		return st.DeleteBucket(tx, store.BucketUsers)
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 
-	st.View(ctx, func(tx *bbolt.Tx) error {
+	if err := st.View(ctx, func(tx *bbolt.Tx) error {
 		if st.BucketExists(tx, store.BucketUsers) {
 			t.Fatal("expected bucket to be deleted")
 		}
 		return nil
-	})
+	}); err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestDeleteBucketNonExistent(t *testing.T) {