Revert what seems to be a typo introduced as part of the fix for #2041
in 2018 7d0f2eaf24.
`xbuild` does not look like a go build/tag keyword to me, I failed to
find documentation for it and using `go install -tags '!selfupdate' ...`
has no effect, i.e. self-update code is still compiled.
`+build` however works; updating the OpenBSD port/binary package
security/restic to apply this PR works as expected:
```
$ restic help | grep self
$ restic self-update
unknown command "self-update" for "restic"
```
(Using `go:build` now as per restic's style and gofmt.)
Previously, using `restic-0.14.0p1` on OpenBSD/amd64 7.2-current would
check for a newer version and probably attempt replacing the system wide
root-owned executable (on a read-only filesystem) as unprivileged user:
```
$ restic version
restic 0.14.0 compiled with go1.19.2 on openbsd/amd64
$ restic help | grep self
self-update Update the restic binary
$ restic self-update
writing restic to /usr/local/bin/restic
find latest release of restic at GitHub
restic is up to date
```
(It never tried to actually write besaid path; doing so would fail, so
the current message can be considered misleading.)
Mostly changed the ones that repeat the name of a system call, which is
already contained in os.PathError.Op. internal/fs.Reader had to be
changed to actually return such errors.
The scanner process has only cosmetic effect for the progress printer,
and can be disabled without impacting functionality when the user does
not need an estimate of completion.
In many cases the scanner process can provide beneficial priming of
the file system cache, so as general advice it should not be disabled.
However, tests have shown that backup of NFS and fuse based filesystems,
where stat(2) is relatively expensive, can be significantly faster
without the scanner.
TestRepository and its variants always returned no-op cleanup functions.
If they ever do need to do cleanup, using testing.T.Cleanup is easier
than passing these functions around.
The Original field is meant to remember the original snapshot id if e.g.
changing its tags. It was only set by the `rewrite` command if it was
not set previously. However, a rewritten snapshot is potentially rather
different from the original snapshot. Thus just always set the Original
field. This also makes it easier to later on detect and potentially
remove the original snapshots.
We now check for space that is not reserved for the root user on the
remote, and the check is no longer in a defer block because it wouldn't
fire. Some change in the surrounding code may have led the deferred
function to capture the wrong err variable.
Fixes #3336.
