[mythtv-users] Using XMLTV source with mythexternrecorder keeps adding additional channels

[OpenMedia Support]

> I've got two IPTV recorders defined that utilise the same xmltv feed.
>
> IPTVNZ is a FreeBox device
>  - 12 channels defined via iptv-nz.m3u8
>  - Video Source IPTV_NZ  -> NZ xmltv epg feed with 30 channels
>
> VLCNZ is an EXTERNAL device with 16 channels defined via
>  - 16 channels defined via vlc-nz-channels.conf
>  - Video Source VLC_NZ  -> NZ xmltv epg feed with 30 channels
>
> The grabber uses the same EPG data but I have two different sources to
> avoid confusion.
>
> running mythfilldatabase the IPTVNZ channel listing stays the same and any
> non-matching channels in the EPG file are flagged and ignored.
>
> 2020-06-16 14:57:05.029634 I  XMLTV config file is:
> /home/mythfe/.mythtv/IPTV NZ.xmltv
> 2020-06-16 14:57:06.035537 N  Unknown xmltv channel identifier: tv.11 -
> Skipping channel.
> 2020-06-16 14:57:06.035737 N  Unknown xmltv channel identifier: tv.12 -
> Skipping channel.
> 2020-06-16 14:57:06.717274 N  Unknown xmltv channel identifier: tv.21 -
> Skipping channel.
>
> Whilst with the EXTERNAL Feed the additional channels, which I don't want
> to load into my MythTV environment, get added against the "VLC NZ"
> sourceid.
>
> 2020-06-16 14:57:14.592501 I  XMLTV config file is:
> /home/mythfe/.mythtv/VLC NZ.xmltv
> 2020-06-16 14:57:20.231268 I  Updated programs: 53 Unchanged programs:
> 5499
> 2020-06-16 14:57:20.262160 N  Data fetching complete.
>
>
> These are both using the same EPG data file https://i.mjh.nz/nz/epg.xml.gz
> so I don't understand why one tuner/source works as I expect and the other
> tuner doesn't.
>
> I've taken a look at the code under
>  - libs/libmythtv/programdata.cpp
> and in theory it should work as I expect. At present the only work around
> I've got is to tag the unwanted channels as NOT visible.

Ok digging a little deeper

Looking at ./mythtv/mythtv/programs/mythfilldatabase/channeldata.cpp
 - bool ChannelData::insert_chan(uint sourceid) is returning true

and then

Looking at ./mythtv/mythtv/libs/libmythtv/cardutil.h
 - EXTERNAL isn't IsUnscanable so that can't be the trigger
 - EXTERNAL isn't IsEncoder so that must be the trigger

AS I can defined a scanner/tuner for an EXTERNAL device isn't this logic
wrong, or do we need this logic for another part of MythTV?

Steven