Support partial updates in UpdateSettings

Author: bitcoin-coder-bob

internal/core/application/admin.go

@@ -623,13 +623,25 @@ func (a *adminService) GetSettings(ctx context.Context) (*domain.Settings, error
 }
 
 func (a *adminService) UpdateSettings(ctx context.Context, settings domain.Settings) error {
+	a.settingsMu.Lock()
+	defer a.settingsMu.Unlock()
+
+	// Merge with current settings so callers can send only the fields they
+	// want to change (zero-valued fields inherit the existing value).
+	current, err := a.repoManager.Settings().Get(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to get current settings: %w", err)
+	}
+	// nil means no settings exist yet (first boot) so then skip merge 
+	// so caller's full settings are used as-is.
+	if current != nil {
+		settings = settings.Merge(*current)
+	}
+
 	if err := settings.Validate(); err != nil {
 		return err
 	}
 
-	a.settingsMu.Lock()
-	defer a.settingsMu.Unlock()
-
 	// Apply to the running service before persisting so that if live-apply
 	// fails we don't leave invalid settings in the DB.
 	if a.onSettingsUpdated != nil {

internal/core/application/admin_test.go

@@ -132,6 +132,28 @@ func TestAdminService_Settings(t *testing.T) {
 		assert.Equal(t, int64(7200), got.SettlementMinExpiryGap)
 	})
 
+	t.Run("partial update only changes provided fields", func(t *testing.T) {
+		// Get current state after the full update above.
+		before, err := svc.GetSettings(ctx)
+		require.NoError(t, err)
+
+		// Send only BanThreshold — everything else is zero.
+		partial := domain.Settings{BanThreshold: 99}
+		err = svc.UpdateSettings(ctx, partial)
+		require.NoError(t, err)
+
+		got, err := svc.GetSettings(ctx)
+		require.NoError(t, err)
+		require.NotNil(t, got)
+		assert.Equal(t, int64(99), got.BanThreshold)
+		// Other fields unchanged.
+		assert.Equal(t, before.BanDuration, got.BanDuration)
+		assert.Equal(t, before.UnilateralExitDelay, got.UnilateralExitDelay)
+		assert.Equal(t, before.BoardingExitDelay, got.BoardingExitDelay)
+		assert.Equal(t, before.VtxoTreeExpiry, got.VtxoTreeExpiry)
+		assert.Equal(t, before.MaxTxWeight, got.MaxTxWeight)
+	})
+
 	t.Run("clear resets settings to defaults", func(t *testing.T) {
 		err := svc.ClearSettings(ctx)
 		require.NoError(t, err)

internal/core/domain/settings.go

@@ -128,6 +128,61 @@ func (s Settings) Validate() error {
 	return nil
 }
 
+// Merge returns a copy of s where any zero-valued field is replaced by the
+// corresponding value from other. This allows callers to send only the fields
+// they want to change.
+func (s Settings) Merge(other Settings) Settings {
+	if s.BanThreshold == 0 {
+		s.BanThreshold = other.BanThreshold
+	}
+	if s.BanDuration == 0 {
+		s.BanDuration = other.BanDuration
+	}
+	if s.UnilateralExitDelay == 0 {
+		s.UnilateralExitDelay = other.UnilateralExitDelay
+	}
+	if s.PublicUnilateralExitDelay == 0 {
+		s.PublicUnilateralExitDelay = other.PublicUnilateralExitDelay
+	}
+	if s.CheckpointExitDelay == 0 {
+		s.CheckpointExitDelay = other.CheckpointExitDelay
+	}
+	if s.BoardingExitDelay == 0 {
+		s.BoardingExitDelay = other.BoardingExitDelay
+	}
+	if s.VtxoTreeExpiry == 0 {
+		s.VtxoTreeExpiry = other.VtxoTreeExpiry
+	}
+	if s.RoundMinParticipantsCount == 0 {
+		s.RoundMinParticipantsCount = other.RoundMinParticipantsCount
+	}
+	if s.RoundMaxParticipantsCount == 0 {
+		s.RoundMaxParticipantsCount = other.RoundMaxParticipantsCount
+	}
+	if s.VtxoMinAmount == 0 {
+		s.VtxoMinAmount = other.VtxoMinAmount
+	}
+	if s.VtxoMaxAmount == 0 {
+		s.VtxoMaxAmount = other.VtxoMaxAmount
+	}
+	if s.UtxoMinAmount == 0 {
+		s.UtxoMinAmount = other.UtxoMinAmount
+	}
+	if s.UtxoMaxAmount == 0 {
+		s.UtxoMaxAmount = other.UtxoMaxAmount
+	}
+	if s.SettlementMinExpiryGap == 0 {
+		s.SettlementMinExpiryGap = other.SettlementMinExpiryGap
+	}
+	if s.VtxoNoCsvValidationCutoffDate == 0 {
+		s.VtxoNoCsvValidationCutoffDate = other.VtxoNoCsvValidationCutoffDate
+	}
+	if s.MaxTxWeight == 0 {
+		s.MaxTxWeight = other.MaxTxWeight
+	}
+	return s
+}
+
 func NewSettings(
 	banThreshold, banDuration,
 	unilateralExitDelay, publicUnilateralExitDelay,

internal/core/domain/settings_test.go

@@ -144,6 +144,30 @@ func TestSettings_Validate(t *testing.T) {
 		}
 	})
 
+	t.Run("merge fills zero fields from other", func(t *testing.T) {
+		current := validSettings()
+		partial := Settings{BanThreshold: 10}
+		merged := partial.Merge(current)
+
+		assert.Equal(t, int64(10), merged.BanThreshold)
+		assert.Equal(t, current.BanDuration, merged.BanDuration)
+		assert.Equal(t, current.UnilateralExitDelay, merged.UnilateralExitDelay)
+		assert.Equal(t, current.BoardingExitDelay, merged.BoardingExitDelay)
+		assert.Equal(t, current.VtxoTreeExpiry, merged.VtxoTreeExpiry)
+		assert.Equal(t, current.MaxTxWeight, merged.MaxTxWeight)
+		require.NoError(t, merged.Validate())
+	})
+
+	t.Run("merge preserves all set fields", func(t *testing.T) {
+		current := validSettings()
+		full := validSettings()
+		full.BanThreshold = 99
+		merged := full.Merge(current)
+
+		assert.Equal(t, int64(99), merged.BanThreshold)
+		assert.Equal(t, full.BanDuration, merged.BanDuration)
+	})
+
 	t.Run("min exceeds max", func(t *testing.T) {
 		t.Run("vtxo", func(t *testing.T) {
 			s := validSettings()