fix(GODT-2319): seed the math/rand RNG on app startup.

internal/app/app.go

@@ -19,11 +19,13 @@ package app
 
 import (
 	"fmt"
+	"math/rand"
 	"net/http"
 	"net/http/cookiejar"
 	"os"
 	"path/filepath"
 	"runtime"
+	"time"
 
 	"github.com/Masterminds/semver/v3"
 	"github.com/ProtonMail/proton-bridge/v3/internal/bridge"
@@ -155,6 +157,9 @@ func New() *cli.App { //nolint:funlen
 }
 
 func run(c *cli.Context) error { //nolint:funlen
+	// Seed the default RNG from the math/rand package.
+	rand.Seed(time.Now().UnixNano())
+
 	// Get the current bridge version.
 	version, err := semver.NewVersion(constants.Version)
 	if err != nil {

internal/vault/settings.go

@@ -18,8 +18,16 @@
 package vault
 
 import (
+	"math"
+	"math/rand"
+
 	"github.com/Masterminds/semver/v3"
 	"github.com/ProtonMail/proton-bridge/v3/internal/updater"
+	"github.com/sirupsen/logrus"
+)
+
+const (
+	ForbiddenRollout = 0.6046602879796196
 )
 
 // GetIMAPPort sets the port that the IMAP server should listen on.
@@ -96,7 +104,17 @@ func (vault *Vault) SetUpdateChannel(channel updater.Channel) error {
 
 // GetUpdateRollout sets the update rollout.
 func (vault *Vault) GetUpdateRollout() float64 {
-	return vault.get().Settings.UpdateRollout
+	// The rollout value 0.6046602879796196 is forbidden. The RNG was not seeded when it was picked (GODT-2319).
+	rollout := vault.get().Settings.UpdateRollout
+	if math.Abs(rollout-ForbiddenRollout) >= 0.00000001 {
+		return rollout
+	}
+
+	rollout = rand.Float64() //nolint:gosec
+	if err := vault.SetUpdateRollout(rollout); err != nil {
+		logrus.WithError(err).Warning("Failed writing updateRollout value in vault")
+	}
+	return rollout
 }
 
 // SetUpdateRollout sets the update rollout.

internal/vault/settings_test.go

@@ -18,6 +18,7 @@
 package vault_test
 
 import (
+	"math"
 	"testing"
 
 	"github.com/Masterminds/semver/v3"
@@ -103,6 +104,10 @@ func TestVault_Settings_UpdateRollout(t *testing.T) {
 
 	// Check the new update rollout.
 	require.Equal(t, float64(0.5), s.GetUpdateRollout())
+
+	// Since GODT-2319 0.6046602879796196 is not allowed as a rollout value (RNG was not seeded)
+	require.NoError(t, s.SetUpdateRollout(vault.ForbiddenRollout))
+	require.GreaterOrEqual(t, math.Abs(s.GetUpdateRollout()-vault.ForbiddenRollout), 0.00000001)
 }
 
 func TestVault_Settings_ColorScheme(t *testing.T) {