bisync: support files with unknown length, including Google Docs - fixes

 rclone#5696

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.

cmd/bisync/listing.go

@@ -36,7 +36,7 @@ const ListingHeader = "# bisync listing v1 from"
 // id: "-" (reserved)
 const lineFormat = "%s %8d %s %s %s %q\n"
 
-var lineRegex = regexp.MustCompile(`^(\S) +(\d+) (\S+) (\S+) (\d{4}-\d\d-\d\dT\d\d:\d\d:\d\d\.\d{9}[+-]\d{4}) (".+")$`)
+var lineRegex = regexp.MustCompile(`^(\S) +(-?\d+) (\S+) (\S+) (\d{4}-\d\d-\d\dT\d\d:\d\d:\d\d\.\d{9}[+-]\d{4}) (".+")$`)
 
 // timeFormat defines time format used in listings
 const timeFormat = "2006-01-02T15:04:05.000000000-0700"
@@ -237,7 +237,6 @@ func (ls *fileList) save(ctx context.Context, listing string) error {
 
 // loadListing will load listing from a file.
 // The key is the path to the file relative to the Path1/Path2 base.
-// File size of -1, as for Google Docs, prints a warning and won't be loaded.
 func (b *bisyncRun) loadListing(listing string) (*fileList, error) {
 	file, err := os.Open(listing)
 	if err != nil {

cmd/bisync/march.go

@@ -168,8 +168,7 @@ func (b *bisyncRun) ForDir(o fs.Directory, isPath1 bool) {
 	id := ""     // TODO
 	flags := "d" // "-" for a file and "d" for a directory
 	marchLsLock.Lock()
-	//record size as 0 instead of -1, so bisync doesn't think it's a google doc
-	ls.put(o.Remote(), 0, time, "", id, flags)
+	ls.put(o.Remote(), -1, time, "", id, flags)
 	marchLsLock.Unlock()
 }
 

cmd/bisync/operations.go

@@ -441,8 +441,7 @@ func (b *bisyncRun) resync(octx, fctx context.Context) error {
 	// fctx has our extra filters added!
 	ctxSync, filterSync := filter.AddConfig(ctxRun)
 	if filterSync.Opt.MinSize == -1 {
-		// prevent overwriting Google Doc files (their size is -1)
-		filterSync.Opt.MinSize = 0
+		fs.Debugf(nil, "filterSync.Opt.MinSize: %v", filterSync.Opt.MinSize)
 	}
 	ci := fs.GetConfig(ctxSync)
 	ci.IgnoreExisting = true

cmd/bisync/queue.go

@@ -38,7 +38,9 @@ type Results struct {
 
 var logger = operations.NewLoggerOpt()
 var lock mutex.Mutex
+var once mutex.Once
 var ignoreListingChecksum bool
+var ci *fs.ConfigInfo
 
 // FsPathIfAny handles type assertions and returns a formatted bilib.FsPath if valid, otherwise ""
 func FsPathIfAny(x fs.DirEntry) string {
@@ -121,7 +123,13 @@ func WriteResults(ctx context.Context, sigil operations.Sigil, src, dst fs.DirEn
 				result.Name = dst.Remote()
 			}
 			result.Flags = "d"
-			result.Size = 0
+			result.Size = -1
+		}
+
+		if result.Size < 0 && result.Flags != "d" && (ci.CheckSum || ci.SizeOnly) {
+			once.Do(func() {
+				fs.Logf(result.Name, Color(terminal.YellowFg, "Files of unknown size (such as Google Docs) do not sync reliably with --checksum or --size-only. Consider using modtime instead (the default) or --drive-skip-gdocs"))
+			})
 		}
 
 		fs.Debugf(nil, "writing result: %v", result)
@@ -166,6 +174,7 @@ func (b *bisyncRun) fastCopy(ctx context.Context, fsrc, fdst fs.Fs, files bilib.
 	}
 
 	ignoreListingChecksum = b.opt.IgnoreListingChecksum
+	ci = fs.GetConfig(ctx)
 	logger.LoggerFn = WriteResults
 	ctxCopyLogger := operations.WithSyncLogger(ctxCopy, logger)
 	b.testFn()
@@ -194,6 +203,7 @@ func (b *bisyncRun) retryFastCopy(ctx context.Context, fsrc, fdst fs.Fs, files b
 }
 
 func (b *bisyncRun) resyncDir(ctx context.Context, fsrc, fdst fs.Fs) ([]Results, error) {
+	ci = fs.GetConfig(ctx)
 	ignoreListingChecksum = b.opt.IgnoreListingChecksum
 	logger.LoggerFn = WriteResults
 	ctxCopyLogger := operations.WithSyncLogger(ctx, logger)

docs/content/bisync.md

@@ -883,23 +883,62 @@ files are generating complaints. If the error is
 consider using the flag
 [--drive-acknowledge-abuse](/drive/#drive-acknowledge-abuse).
 
-### Google Doc files
-
-Google docs exist as virtual files on Google Drive and cannot be transferred
-to other filesystems natively. While it is possible to export a Google doc to
-a normal file (with `.xlsx` extension, for example), it is not possible
-to import a normal file back into a Google document.
-
-Bisync's handling of Google Doc files is to flag them in the run log output
-for user's attention and ignore them for any file transfers, deletes, or syncs.
-They will show up with a length of `-1` in the listings.
-This bisync run is otherwise successful:
-
-```
-2021/05/11 08:23:15 INFO  : Synching Path1 "/path/to/local/tree/base/" with Path2 "GDrive:"
-2021/05/11 08:23:15 INFO  : ...path2.lst-new: Ignoring incorrect line: "- -1 - - 2018-07-29T08:49:30.136000000+0000 GoogleDoc.docx"
-2021/05/11 08:23:15 INFO  : Bisync successful
-```
+### Google Docs (and other files of unknown size) {#gdocs}
+
+As of `v1.65`, [Google Docs](/drive/#import-export-of-google-documents)
+(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`](/drive/#drive-export-formats) (default
+`"docx,xlsx,pptx,svg"`) and the non-drive -> drive direction is controlled by
+[`--drive-import-formats`](/drive/#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](https://rclone.org/drive/#exportformats:~:text=available%20Google%20Documents.-,Extension,macOS,-Standard%20options).)
+
+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`](/drive/#drive-skip-gdocs).
+
+(Note that all flags starting with `--drive` are backend-specific, and
+therefore will cause the behavior explained in [Overridden
+Configs](/#overridden-configs).)
 
 ## Usage examples
 
@@ -1289,6 +1328,7 @@ about _Unison_ and synchronization in general.
 for performance improvements and less [risk of error](https://forum.rclone.org/t/bisync-bugs-and-feature-requests/37636#:~:text=4.%20Listings%20should%20alternate%20between%20paths%20to%20minimize%20errors).
 * Fixed handling of unicode normalization and case insensitivity, support for [`--fix-case`](/docs/#fix-case), [`--ignore-case-sync`](/docs/#ignore-case-sync), [`--no-unicode-normalization`](/docs/#no-unicode-normalization)
 * `--resync` is now much more efficient (especially for users of `--create-empty-src-dirs`)
+* Google Docs (and other files of unknown size) are now supported (with the same options as in `sync`)
 
 ### `v1.64`
 * Fixed an [issue](https://forum.rclone.org/t/bisync-bugs-and-feature-requests/37636#:~:text=1.%20Dry%20runs%20are%20not%20completely%20dry)