fix panic when reading team features from the database (#7633)

This fixes an unreleased bug I introduced in eeefe2, as the config colum in the teams table is nulleable, it unmarshalls into nil and we can't dereference the variable

server/datastore/mysql/teams.go

@@ -308,9 +308,13 @@ func (ds *Datastore) TeamFeatures(ctx context.Context, tid uint) (*fleet.Feature
 	if err := sqlx.GetContext(ctx, ds.reader, &raw, sql, tid); err != nil {
 		return nil, ctxerr.Wrap(ctx, err, "get team config features")
 	}
+
 	var features fleet.Features
-	if err := json.Unmarshal(*raw, &features); err != nil {
-		return nil, ctxerr.Wrap(ctx, err, "unmarshal team config features")
+	features.ApplyDefaultsForNewInstalls()
+	if raw != nil {
+		if err := json.Unmarshal(*raw, &features); err != nil {
+			return nil, ctxerr.Wrap(ctx, err, "unmarshal team config features")
+		}
 	}
 	return &features, nil
 }

server/datastore/mysql/teams_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/fleetdm/fleet/v4/server/fleet"
 	"github.com/fleetdm/fleet/v4/server/ptr"
 	"github.com/fleetdm/fleet/v4/server/test"
+	"github.com/jmoiron/sqlx"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -30,6 +31,7 @@ func TestTeams(t *testing.T) {
 		{"TeamAgentOptions", testTeamsAgentOptions},
 		{"TeamsDeleteRename", testTeamsDeleteRename},
 		{"DeleteIntegrationsFromTeams", testTeamsDeleteIntegrationsFromTeams},
+		{"TeamsFeatures", testTeamsFeatures},
 	}
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
@@ -424,3 +426,65 @@ func testTeamsDeleteIntegrationsFromTeams(t *testing.T, ds *Datastore) {
 	require.NoError(t, err)
 	assertIntgURLs([]string{urld}, []string{urle, urlf}, []string{urle, urlf})
 }
+
+func testTeamsFeatures(t *testing.T, ds *Datastore) {
+	defaultFeatures := fleet.Features{}
+	defaultFeatures.ApplyDefaultsForNewInstalls()
+	ctx := context.Background()
+
+	t.Run("NULL config in the database", func(t *testing.T) {
+		team, err := ds.NewTeam(ctx, &fleet.Team{Name: "team_null_config"})
+		require.NoError(t, err)
+		ExecAdhocSQL(t, ds, func(tx sqlx.ExtContext) error {
+			_, err = tx.ExecContext(
+				ctx,
+				"UPDATE teams SET config = NULL WHERE id = ?",
+				team.ID,
+			)
+			return err
+		})
+		features, err := ds.TeamFeatures(ctx, team.ID)
+		require.NoError(t, err)
+
+		assert.Equal(t, &defaultFeatures, features)
+	})
+
+	t.Run("NULL config.features in the database", func(t *testing.T) {
+		team, err := ds.NewTeam(ctx, &fleet.Team{Name: "team_null_config_features"})
+		require.NoError(t, err)
+		ExecAdhocSQL(t, ds, func(tx sqlx.ExtContext) error {
+			_, err = tx.ExecContext(
+				ctx,
+				"UPDATE teams SET config = '{}' WHERE id = ?",
+				team.ID,
+			)
+			return err
+		})
+		features, err := ds.TeamFeatures(ctx, team.ID)
+		require.NoError(t, err)
+
+		assert.Equal(t, &defaultFeatures, features)
+	})
+
+	t.Run("saves and retrieves configs", func(t *testing.T) {
+		team, err := ds.NewTeam(ctx, &fleet.Team{
+			Name: "team1",
+			Config: fleet.TeamConfig{
+				Features: fleet.Features{
+					EnableHostUsers:         false,
+					EnableSoftwareInventory: false,
+					AdditionalQueries:       nil,
+				},
+			},
+		})
+		require.NoError(t, err)
+		features, err := ds.TeamFeatures(ctx, team.ID)
+		require.NoError(t, err)
+
+		assert.Equal(t, &fleet.Features{
+			EnableHostUsers:         false,
+			EnableSoftwareInventory: false,
+			AdditionalQueries:       nil,
+		}, features)
+	})
+}