Installation fails over existing ZFS

[Olivier Gayot]

Multiple private reports show that installs over an existing ZFS install are failing. In those reports, the ProbeData.txt file show:

    "zfs": {
        "zpools": {}
    },
    "filesystem": {
        "/dev/sda": {
            "LABEL": "rpool",
            "LABEL_ENC": "rpool",
            "TYPE": "zfs_member"

or something equivalent.

And the associated error in subiquity log file is:

ValueError: Partition(device=disk-sda, size=xxx, wipe='superblock', number=1, preserve=True, offset=xxx, partition_type='xxx', path='/dev/sda1', type='partition', id='partition-sda1') is not in list

I don't have a reproducer for now. I tried a guided install over a 22.10 ZFS install (done with Ubiquity) but it didn't produce a failure. If anybody can reproduce it the issue at will, please share your setup :)