Magic Folder: miscounting in magic_folder.uploader.objects_queued

[daira]

(follow-on from #2709)

Raw Stats:

{'counters': {'magic_folder.uploader.directories_created': 1,
              'magic_folder.uploader.dirs_monitored': 1,
              'magic_folder.uploader.objects_not_uploaded': 3,
              'magic_folder.uploader.objects_queued': -1,
              'magic_folder.uploader.objects_succeeded': 4,
              'mutable.bytes_published': 385,
              'mutable.bytes_retrieved': 36194,
              'mutable.files_published': 1,
              'mutable.files_retrieved': 83,
              'uploader.bytes_uploaded': 0,
              'uploader.files_uploaded': 1},
[...]

'magic_folder.uploader.objects_queued': -1 indicates miscounting somewhere.

[dawuud]

using only the unit tests i was able to find evidence that at least the Downloader is affected by this bug:

(virtenv-tahoe-lafs)user@tahoe-dev:~/tahoe-lafs$ grep 'now \-1' ,1 | wc -l
28
(virtenv-tahoe-lafs)user@tahoe-dev:~/tahoe-lafs$ grep 'now \-1' ,1
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-0' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-0' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-0' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-0' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-0' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-0' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-0' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-0' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-0' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-0' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-0' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += 0 (now -1)
Magic Folder 'client-0' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-0' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)
Magic Folder 'client-1' downloader: objects_queued += -1 (now -1)

i theorize this happens because directories are added to the deque as a single item and the child are decremented individually cause the negative count.

[daira]

This is fixed on 2438.magic-folder-stable.13 (d5b494b618854eddda8f9452912a8693ae3adab9).

[Brian Warner <warner@…>]

In e67d23b/trunk:

Fix negative counts for object_queued. fixes ticket:2731

Signed-off-by: Daira Hopwood <daira@…>