"Zombie Dragons": Magic-folders continue to sync after leaving

[cypher]

After calling a tahoe magic-folder leave -n FolderName I notice -- by looking at the tahoe run logs/output -- that tahoe will continue to process filesystem events and perform uploads for the very folder that I have just left. Somewhat deceivingly, after leaving, the tahoe magic-folder status -n FolderName reports Error: no such folder 'FolderName' (suggesting that the folder has indeed been properly "left"), however, I can still read the status API for that folder directly through the web/json interface (suggesting, in contrast, that the folder remains joined/active in some way).

As a user, I would expect that the act of "leaving" a folder (in this case, by calling the leave CLI subcommand) would also cause that folder to stop syncing immediately and altogether, while, as a developer, I would expect the web/json API to no longer return status information for a folder that has been "left". Neither seems to be the case, however, and it appears as though a tahoe restart is needed to fully "leave" a magic-folder.

Since I'm not sure what the correct/intended behavior is here, there seem to be two paths for resolving this: Either a) stop syncing (and stop making available status information via the WAPI) immediately for any folders that have been "left", or b) indicate to the user via the CLI that a tahoe restart is necessary to actually "leave" a magic-folder upon leaving.

[exarkun]

magic-folder has been split out into a separate project - ​https://github.com/leastauthority/magic-folder