Bisync checks file equality before renaming sync conflicts by comparing
checksums. Before this change, backends without checksum support (notably
Crypt) would fall back to --size-only for these checks, which is not a very
safe method (differing files can sometimes have the same size, especially if
they're small.) After this change, Crypt remotes fallback to using Cryptcheck
so that checksums can be compared. As a last resort when neither Check nor
Cryptcheck are available, files are compared using --download so that we can be
certain the files are identical regardless of checksum support.
Before this change, bisync intentionally ignored Google Docs (albeit in a
buggy way that caused problems during --resync.) After this change, Google Docs
(including Google Sheets, Slides, etc.) are now supported in bisync, subject to
the same options, defaults, and limitations as in `rclone sync`. When bisyncing
drive with non-drive backends, the drive -> non-drive direction is controlled
by `--drive-export-formats` (default `"docx,xlsx,pptx,svg"`) and the non-drive
-> drive direction is controlled by `--drive-import-formats` (default none.)
For example, with the default export/import formats, a Google Sheet on the
drive side will be synced to an `.xlsx` file on the non-drive side. In the
reverse direction, `.xlsx` files with filenames that match an existing Google
Sheet will be synced to that Google Sheet, while `.xlsx` files that do NOT
match an existing Google Sheet will be copied to drive as normal `.xlsx` files
(without conversion to Sheets, although the Google Drive web browser UI may
still give you the option to open it as one.)
If `--drive-import-formats` is set (it's not, by default), then all of the
specified formats will be converted to Google Docs, if there is no existing
Google Doc with a matching name. Caution: such conversion can be quite lossy,
and in most cases it's probably not what you want!
To bisync Google Docs as URL shortcut links (in a manner similar to "Drive for
Desktop"), use: `--drive-export-formats url` (or alternatives.)
Note that these link files cannot be edited on the non-drive side -- you will
get errors if you try to sync an edited link file back to drive. They CAN be
deleted (it will result in deleting the corresponding Google Doc.) If you
create a `.url` file on the non-drive side that does not match an existing
Google Doc, bisyncing it will just result in copying the literal `.url` file
over to drive (no Google Doc will be created.) So, as a general rule of thumb,
think of them as read-only placeholders on the non-drive side, and make all
your changes on the drive side.
Likewise, even with other export-formats, it is best to only move/rename Google
Docs on the drive side. This is because otherwise, bisync will interpret this
as a file deleted and another created, and accordingly, it will delete the
Google Doc and create a new file at the new path. (Whether or not that new file
is a Google Doc depends on `--drive-import-formats`.)
Lastly, take note that all Google Docs on the drive side have a size of `-1`
and no checksum. Therefore, they cannot be reliably synced with the
`--checksum` or `--size-only` flags. (To be exact: they will still get
created/deleted, and bisync's delta engine will notice changes and queue them
for syncing, but the underlying sync function will consider them identical and
skip them.) To work around this, use the default (modtime and size) instead of
`--checksum` or `--size-only`.
To ignore Google Docs entirely, use `--drive-skip-gdocs`.
Nearly all of the Google Docs logic is outsourced to the Drive backend, so
future changes should also be supported by bisync.
Refactored the case / unicode normalization logic to be much more efficient,
and fix the last outstanding issue from #7270. Before this change, we were
doing lots of for loops and re-normalizing strings we had already normalized
earlier. Now, we leave the normalizing entirely to March and avoid
re-transforming later, which seems to make a large difference in terms of
performance.
Before this change, --resync was handled in three steps, and needed to do a lot
of unnecessary work to implement its own --ignore-existing logic, which also
caused problems with unicode normalization, in addition to being pretty slow.
After this change, it is refactored to produce the same result much more
efficiently, by reducing the three steps to two and letting ci.IgnoreExisting
do the work instead of reinventing the wheel.
The behavior and sync order remain unchanged for now -- just faster (but see
the ongoing lively discussions about potential future changes in #5681!)
Before this change, Bisync sometimes normalized NFD to NFC and sometimes
did not, causing errors in some scenarios (particularly for users of macOS).
It was similarly inconsistent in its handling of case-insensitivity.
There were three main places where Bisync should have normalized, but didn't:
1. When building the list of files that need to be transferred during --resync
2. When building the list of deltas during a non-resync
3. When comparing Path1 to Path2 during --check-sync
After this change, 1 and 3 are resolved, and bisync supports
--no-unicode-normalization and --ignore-case-sync in the same way as sync.
2 will be addressed in a future update.
Before this change, bisync needed to build a full listing for Path1, then a
full listing for Path2, then compare them -- and each of those tasks needed to
finish before the next one could start. In addition to being slow and
inefficient, it also caused real problems if a file changed between the time
bisync checked it on Path1 and the time it checked the corresponding file on
Path2.
This change solves these problems by listing both paths concurrently, using
the same March infrastructure that check and sync use to traverse two
directories in lock-step, optimized by Go's robust concurrency support.
Listings should now be much faster, and any given path is now checked
nearly-instantaneously on both sides, minimizing room for error.
Further discussion:
https://forum.rclone.org/t/bisync-bugs-and-feature-requests/37636#:~:text=4.%20Listings%20should%20alternate%20between%20paths%20to%20minimize%20errors
Before this change, bisync had no mechanism for "retrying" a file again next
time, in the event of an unexpected and possibly temporary error. After this
change, bisync is now essentially able to mark a file as needing to be
rechecked next time. Bisync does this by keeping one prior listing on hand at
all times. In a low-confidence situation, bisync can revert a given file row
back to its state at the end of the last known successful sync, ensuring that
any subsequent changes will be re-noticed on the next run.
This can potentially be helpful for a dynamically changing file system, where
files may be changing quickly while bisync is working with them.
Before this change, if --create-empty-src-dirs was specified, bisync would
include directories in the list of deltas to evaluate by their modtime,
relative to the prior sync. This was unnecessary, as rclone does not yet
support setting modtime for directories.
After this change, we skip directories when comparing modtimes. (In other
words, we care only if a directory is created or deleted, not whether it is
newer or older.)
Before this change, if there were changes to sync, bisync listed each path
twice: once before the sync and once after. The second listing caused quite
a lot of problems, in addition to making each run much slower and more
expensive. A serious side-effect was that file changes could slip through
undetected, if they happened to occur while a sync was running (between the
first and second listing snapshots.)
After this change, the second listing is eliminated by getting the underlying
sync operation to report back a list of what it changed. Not only is this more
efficient, but also much more robust to concurrent modifications. It should no
longer be necessary to avoid make changes while it's running -- bisync will
simply learn about those changes next time and handle them on the next run.
Additionally, this also makes --check-sync usable again.
For further discussion, see:
https://forum.rclone.org/t/bisync-bugs-and-feature-requests/37636#:~:text=5.%20Final%20listings%20should%20be%20created%20from%20initial%20snapshot%20%2B%20deltas%2C%20not%20full%20re%2Dscans%2C%20to%20avoid%20errors%20if%20files%20changed%20during%20sync
This is possible now that we no longer support go1.12 and brings
rclone into line with standard practices in the Go world.
This also removes errors.New and errors.Errorf from lib/errors and
prefers the stdlib errors package over lib/errors.
