Handle m3u playlists containing relative paths correctly

[andreyponomarevru]

Current behavior: when you create a playlist in VLC and save it, the m3u file contains absolute paths, which are parsed and handled 100% correctly. But if you create and save a playlist in Quod Libet, it always contains relative paths to tracks — and currently such paths are not supported, the script throws the error (see below):

yarn run extracttracklist ../mixes_mine/2024\ -\ 03.12.2024/deep.m3u 
yarn run v1.22.19
$ npx tsx ./src/m3u-to-tracklist '../mixes_mine/2024 - 03.12.2024/deep.m3u'
The following M3U file paths are broken: 

../../tracks/1988 EP/03 Full Moon.flac
../../tracks/Manuel Darquart - The Adriatic EP/03 - Lovin' U.flac
../../inbox-new/2014 - Moonlight Fantasy/02 Illusions.flac
../../tracks/01 - Larry Heard - Guidance (Calm).flac
../../tracks/Seafoam - Easy Tiger EP (2024) [WEB FLAC]/01 Seafoam - Easy Tiger.flac
../../tracks/Dubbyman-Obsession-(ISSUES02)-24BIT-WEB-FLAC-2023-dh/04-dubbyman--obsession_(estrato_aurora_pink_houses_reshape)-dh.flac
../../tracks/02. 30-70 - Tastes Like Freedom (Chaos In The CBD Remix).flac
../../tracks/Gilbert-Astral_Harmonics-(DWT013)-WEB-2024/02-Gilbert-Quantum_Echoes.flac
../../tracks/01-Global_Communication-Incidental_Harmony.flac
../../tracks/6 - Steamfunk.flac
../../inbox-new/Hugo LX - The Platinum Wave/04 - Zio.flac
../../tracks/Glenn Underground - The Jerusalem EPs (Peacefrog Records PF066CD 1997)/03 - Glenn Underground - Keep The Hidden Treasures (Tech-no Jaz Mix).flac
../../inbox-new/DJ Sotofett - Drippin For A Tripp (Tripp-A-Dubb-Mix) 16-48 FLAC/B2 - Nimbus-Mix.flac
npm notice
npm notice New major version of npm available! 10.8.3 -> 11.0.0
npm notice Changelog: https://github.com/npm/cli/releases/tag/v11.0.0
npm notice To update run: npm install -g [email protected]
npm notice
Done in 5.01s.

The m3u playlist saved in Quod Libet and producing the error shown above looks as follows:

#EXTM3U
#EXTINF:304,Byron The Aquarius, MDMA - Full Moon
../../tracks/1988 EP/03 Full Moon.flac
#EXTINF:402,Manuel Darquart - Lovin' U
../../tracks/Manuel Darquart - The Adriatic EP/03 - Lovin' U.flac
#EXTINF:446,Vincent Floyd - Illusions
../../inbox-new/2014 - Moonlight Fantasy/02 Illusions.flac
#EXTINF:746,Larry Heard - Guidance (Calm)
../../tracks/01 - Larry Heard - Guidance (Calm).flac
#EXTINF:433,Seafoam - Easy Tiger
../../tracks/Seafoam - Easy Tiger EP (2024) [WEB FLAC]/01 Seafoam - Easy Tiger.flac
#EXTINF:422,Dubbyman - Obsession (Estrato Aurora Pink Houses Reshape)
../../tracks/Dubbyman-Obsession-(ISSUES02)-24BIT-WEB-FLAC-2023-dh/04-dubbyman--obsession_(estrato_aurora_pink_houses_reshape)-dh.flac
#EXTINF:350,30/70, Allysha Joy - Tastes Like Freedom (Chaos In The CBD Remix)
../../tracks/02. 30-70 - Tastes Like Freedom (Chaos In The CBD Remix).flac
#EXTINF:324,Gilbert - Quantum Echoes
../../tracks/Gilbert-Astral_Harmonics-(DWT013)-WEB-2024/02-Gilbert-Quantum_Echoes.flac
#EXTINF:521,Global Communication - Incidental Harmony
../../tracks/01-Global_Communication-Incidental_Harmony.flac
#EXTINF:364,D'Marc Cantu - Steamfunk
../../tracks/6 - Steamfunk.flac
#EXTINF:300,Hugo LX, Christopher Johnson - Zio
../../inbox-new/Hugo LX - The Platinum Wave/04 - Zio.flac
#EXTINF:406,Glenn Underground - Keep The Hidden Treasures (Tech-no Jaz Mix)
../../tracks/Glenn Underground - The Jerusalem EPs (Peacefrog Records PF066CD 1997)/03 - Glenn Underground - Keep The Hidden Treasures (Tech-no Jaz Mix).flac
#EXTINF:537,DJ Sotofett, Jaakko Eino Kalevi, Phillip Lauer - Nimbus-Mix
../../inbox-new/DJ Sotofett - Drippin For A Tripp (Tripp-A-Dubb-Mix) 16-48 FLAC/B2 - Nimbus-Mix.flac

Current solution is to open an m3u file in VLC and save it again, it will silently convert paths to absolute ones, so the playlist will look as follows:

#EXTM3U
#EXTM3U
#EXTINF:304,Byron The Aquarius MDMA - Full Moon
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/1988%20EP/03%20Full%20Moon.flac
#EXTINF:402,Manuel Darquart - Lovin' U
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/Manuel%20Darquart%20-%20The%20Adriatic%20EP/03%20-%20Lovin'%20U.flac
#EXTINF:446,Vincent Floyd - Illusions
file:///mnt/CE64EB6A64EB53AD/music-lib/inbox-new/2014%20-%20Moonlight%20Fantasy/02%20Illusions.flac
#EXTINF:746,Larry Heard - Guidance (Calm)
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/01%20-%20Larry%20Heard%20-%20Guidance%20(Calm).flac
#EXTINF:422,Dubbyman - Obsession (Estrato Aurora Pink Houses Reshape)
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/Dubbyman-Obsession-(ISSUES02)-24BIT-WEB-FLAC-2023-dh/04-dubbyman--obsession_(estrato_aurora_pink_houses_reshape)-dh.flac
#EXTINF:350,30/70 - Tastes Like Freedom (Chaos In The CBD Remix)
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/02.%2030-70%20-%20Tastes%20Like%20Freedom%20(Chaos%20In%20The%20CBD%20Remix).flac
#EXTINF:324,Gilbert - Quantum Echoes
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/Gilbert-Astral_Harmonics-(DWT013)-WEB-2024/02-Gilbert-Quantum_Echoes.flac
#EXTINF:521,Global Communication - Incidental Harmony
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/01-Global_Communication-Incidental_Harmony.flac
#EXTINF:364,D'Marc Cantu - Steamfunk
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/6%20-%20Steamfunk.flac
#EXTINF:300,Hugo LX Christopher Johnson - Zio
file:///mnt/CE64EB6A64EB53AD/music-lib/inbox-new/Hugo%20LX%20-%20The%20Platinum%20Wave/04%20-%20Zio.flac
#EXTINF:406,Glenn Underground - Keep The Hidden Treasures (Tech-no Jaz Mix)
file:///mnt/CE64EB6A64EB53AD/music-lib/tracks/Glenn%20Underground%20-%20The%20Jerusalem%20EPs%20(Peacefrog%20Records%20PF066CD%201997)/03%20-%20Glenn%20Underground%20-%20Keep%20The%20Hidden%20Treasures%20(Tech-no%20Jaz%20Mix).flac
#EXTINF:537,DJ Sotofett Jaakko Eino Kalevi Phillip Lauer - Nimbus-Mix
file:///mnt/CE64EB6A64EB53AD/music-lib/inbox-new/DJ%20Sotofett%20-%20Drippin%20For%20A%20Tripp%20(Tripp-A-Dubb-Mix)%2016-48%20FLAC/B2%20-%20Nimbus-Mix.flac

— suck m3u is parsed correctly.