Strange error from magic-folders on 1.19 and master

[meejah]

The test_list_tahoe_objects test has been consistently failing in magic-folder on 1.19 and master.

This does 20 identical magic-folders in parallel and ensures that a particular magic-folder API works. However, one of the folders gets a bigger-than-expected metadata Immutable.

It's not clear whether this is a magic-folder bug or a Tahoe-LAFS bug, but filing it here in case it's Tahoe.

See also ​https://github.com/tahoe-lafs/magic-folder/issues/766

[hacklschorsch]

Chris and I were looking at this. With tahoe-lafs master, the behavior is quite weird - the test seems to fail with the default of number_of_folders = 20, but not with 15 or 30.

[hacklschorsch]

The one folder that is bigger has a parent node:

[flo@vantaa:~/Repositories/tahoe-lafs]$ tahoe -d /tmp/pytest-of-flo/pytest-26/magic-folder0/yolandi get URI:CHK:yjvkmhkph2gickgtaudnyhlo6q:bafwaxkbe4nggm2nm4tirl4wbkuhrqzpsmea2yetyksvln35vlma:1:1:190 | jq
{
  "snapshot_version": 1,
  "relpath": "a_file_name",
  "author": {
    "name": "yolandi",
    "verify_key": "qdNx46+nbgNmglVCKoGARp9WfnDQ5X9mrfaIn24EBU8="
  },
  "modification_time": 1741115643,
  "parents": []
}
(venv)
[flo@vantaa:~/Repositories/tahoe-lafs]$ tahoe -d /tmp/pytest-of-flo/pytest-26/magic-folder0/yolandi get URI:CHK:f2hdewvg7jrcga5aehbvux5fva:7uk7gyywwcuvndfb45uga6khonqpzxc3vpos7ajrl4ugyn5gb4xq:1:1:292 | jq
{
  "snapshot_version": 1,
  "relpath": "a_file_name",
  "author": {
    "name": "yolandi",
    "verify_key": "blJt0K5c1h1qbZLVbaW5IDY0u9z1wPwJrqbsKBUdaU8="
  },
  "modification_time": 1741115643,
  "parents": [
    "URI:DIR2-CHK:x32ehmc76i3hdvftfymll7rndi:b4unncwj4inipxf3wjmqubcfcvxgauyyu3o2yu2qakvkdi42bjgq:1:1:416"
  ]
}

[hacklschorsch]

Why does the second one have a parent? All the others don't.

When is that parent list populated?

[meejah]

that means there's more than one version of that file in that folder.

"shouldn't happen" at least according to the intent of the test ... but obviously a bug somewhere.