Snapshot fails on permission errors even with "ignore errors" set

[mathrick]

This is similar to #1599. Using KopiaUI, I'm trying to define a new snapshot for my homedir, and have set all ignore errors options:

{
    "retention": {},
    "files": {
        "ignore": [
            "Downloads/Film/",
            "Downloads/Anime/",
            "Downloads/ROMs/*.iso",
            "Dev/android-sdk-linux",
            "Dev/android-studio",
            "Dev/doom-emacs",
            "Dev/LispM",
            "Dev/android-ndk-r8b-windows.zip"
        ]
    },
    "errorHandling": {
        "ignoreFileErrors": true,
        "ignoreDirectoryErrors": true,
        "ignoreUnknownTypes": true
    },
    "scheduling": {},
    "compression": {
        "compressorName": "zstd",
        "neverCompress": [
            "*.mp4",
            "*.avi",
            "*.mkv"
        ]
    },
    "actions": {},
    "osSnapshots": {
        "volumeShadowCopy": {}
    },
    "logging": {
        "directories": {},
        "entries": {}
    },
    "upload": {}
}

However, when I run the estimate from the UI, it fails at 1.7GiB reading ~/.dbus:

12:21:26.199 ignored error in .dbus: unable to read directory: open /home/mathrick/.dbus: permission denied
12:21:26.199 ignored error in .: unable to read directory: open /home/mathrick/.dbus: permission denied
12:21:26.199 Included files 10 MB ...100 MB: 25 files, total size 588.4 MB
12:21:26.199 Included files 1 MB ... 10 MB: 248 files, total size 596.5 MB
12:21:26.199 Included files 100 KB... 1 MB: 1476 files, total size 421.9 MB
12:21:26.200 Included files 10 KB ...100 KB: 5790 files, total size 181.2 MB
12:21:26.200 Included files 1 KB ... 10 KB: 11680 files, total size 42 MB
12:21:26.200 Included files 0 B ... 1 KB: 7566 files, total size 2.7 MB
12:21:26.200 Excluded files: None

The same error also causes the actual snapshot to fail file collection -- the snapshot still proceeds, but only sees 1.7GiB total. I have verified that ~/.dbus is the cause, because it works if I manually add it to ignores. However, this is a very scary kind of failure to have, because it means I can't actually trust my backups to contain all the data and I have to manually check for errors even if all the flags are set.

Running 0.17.0 build: 89c8eb47af2e1d5c1d14fe299a0cf7eaac095abf from: kopia/kopia, which is included in the kopia-ui Debian package.

[mathrick]

I let the snapshot run, and it has progressed past the 1.7 GiB mark (meaning it now reports being at 9.2 GiB / 1.7 GiB), so it seems the failure is primarily in estimation. Still, that does mean the policy is not applied equally to estimate and create, and also, it shouldn't have been a fatal error in any case with #690 applied? Frankly, I don't think I understand the purpose of --ignore-*-errors, and the docs don't explain them much at all.