It is a supported feature and you do not need to add the full path. I tested and confirmed that using “Path contains” > “base” added all tracks under my “\Music\Base\” folder.
May be a dumb question, but you did add the folder in your Media Provider settings right? It can’t find the files if it’s not part of your library. If you’ve done that, I see no reason why it wouldn’t work as you have already done.
Also make sure that the “Selected libraries” option (when editing the playlist) includes your provider. It should be set to “All” to always include your tracks, or “Inherit” if you want the playlist to fill with only your currently enabled folders. (On Inherit mode, if you hide the folder in the Source Filter menu, it will also hide those tracks from your Smart Playlist.)
As already stated, make sure to upload logs if you want more specific help. For next time: consider asking in the Discussion section if you have questions that don’t need the dev’s help.
Libray → Playlists → Create smart playlist → Tracks → Add rule → Path and file contains “Drama” → Selected provider / libraries → (default is All) → Save
That works!
But why though? I have two providers in that selection (if I click “Add” )
Local device
All Music (via Gonic)
The reason that I specifically chose “Local device” because I don’t want to use the Gonic service provider. I thought if I use “All”, it would imply it also uses all providers?