channeldb: add MarkConfirmationHeight to OpenChannel

Add the MarkConfirmationHeight method to the OpenChannel struct
to record the block height at which the funding transaction was
first confirmed. Also, introduce the ConfirmationHeight field
to persist this information in the database.

Signed-off-by: Nishant Bansal <nishant.bansal.282003@gmail.com>

channeldb/channel_test.go

@@ -978,6 +978,73 @@ func TestChannelStateTransition(t *testing.T) {
 	require.Empty(t, fwdPkgs, "no forwarding packages should exist")
 }
 
+// TestOpeningChannelTxConfirmation verifies that calling MarkConfirmationHeight
+// correctly updates the confirmed state. It also ensures that calling Refresh
+// on a different OpenChannel updates its in-memory state to reflect the prior
+// MarkConfirmationHeight call.
+func TestOpeningChannelTxConfirmation(t *testing.T) {
+	t.Parallel()
+
+	fullDB, err := MakeTestDB(t)
+	require.NoError(t, err)
+
+	cdb := fullDB.ChannelStateDB()
+
+	// Create a pending channel that was broadcast at height 99.
+	const broadcastHeight = uint32(99)
+	channelState := createTestChannel(
+		t, cdb, pendingHeightOption(broadcastHeight),
+	)
+
+	// Fetch pending channels from the database.
+	pendingChannels, err := cdb.FetchPendingChannels()
+	require.NoError(t, err)
+	require.Len(t, pendingChannels, 1)
+
+	// Verify the broadcast height of the pending channel.
+	require.Equal(
+		t, broadcastHeight, pendingChannels[0].FundingBroadcastHeight,
+	)
+
+	confirmationHeight := broadcastHeight + 1
+
+	// Mark the channel's confirmation height.
+	err = pendingChannels[0].MarkConfirmationHeight(confirmationHeight)
+	require.NoError(t, err)
+
+	// Verify the ConfirmationHeight is updated correctly.
+	require.Equal(
+		t, confirmationHeight, pendingChannels[0].ConfirmationHeight,
+	)
+
+	// Re-fetch the pending channels to confirm persistence.
+	pendingChannels, err = cdb.FetchPendingChannels()
+	require.NoError(t, err)
+	require.Len(t, pendingChannels, 1)
+
+	// Validate the confirmation and broadcast height.
+	require.Equal(
+		t, confirmationHeight, pendingChannels[0].ConfirmationHeight,
+	)
+	require.Equal(
+		t, broadcastHeight, pendingChannels[0].FundingBroadcastHeight,
+	)
+
+	// Ensure the original channel state's confirmation height is not
+	// updated before refresh.
+	require.EqualValues(t, channelState.ConfirmationHeight, 0)
+
+	// Refresh the original channel state.
+	err = channelState.Refresh()
+	require.NoError(t, err)
+
+	// Verify that both channel states now have the same ConfirmationHeight.
+	require.Equal(
+		t, channelState.ConfirmationHeight,
+		pendingChannels[0].ConfirmationHeight,
+	)
+}
+
 func TestFetchPendingChannels(t *testing.T) {
 	t.Parallel()
 
@@ -1007,7 +1074,7 @@ func TestFetchPendingChannels(t *testing.T) {
 	}
 
 	chanOpenLoc := lnwire.ShortChannelID{
-		BlockHeight: 5,
+		BlockHeight: broadcastHeight + 1,
 		TxIndex:     10,
 		TxPosition:  15,
 	}