From: Daira Hopwood <daira@jacaranda.org>
Date: Sun, 25 Oct 2015 13:19:13 +0000 (+0000)
Subject: Describe use of size=None for deleted files. refs ticket:1710.
X-Git-Url: https://git.rkrishnan.org/%5B/frontends/%22file:/configuration.rst?a=commitdiff_plain;h=9e56f426c02f1188bed58a75eacda12b79e6b9d3;p=tahoe-lafs%2Ftahoe-lafs.git

Describe use of size=None for deleted files. refs ticket:1710.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>
---

diff --git a/docs/proposed/magic-folder/remote-to-local-sync.rst b/docs/proposed/magic-folder/remote-to-local-sync.rst
index be897259..26f1825d 100644
--- a/docs/proposed/magic-folder/remote-to-local-sync.rst
+++ b/docs/proposed/magic-folder/remote-to-local-sync.rst
@@ -896,10 +896,20 @@ take this as a signal to rename their copies to the backup filename.
 Note that the entry for this zero-length file has a version number as
 usual, and later versions may restore the file.
 
+When the downloader deletes a file (or renames it to a filename
+ending in ``.backup``) in response to a remote change, a local
+filesystem notification will occur, and we must make sure that this
+is not treated as a local change. To do this we have the downloader
+set the ``size`` field in the magic folder db to ``None`` (SQL NULL)
+just before deleting the file, and suppress notifications for which
+the local file does not exist, and the recorded ``size`` field is
+``None``.
+
 When a Magic Folder client restarts, we can detect files that had
 been downloaded but were deleted while it was not running, because
 their paths will have last-downloaded records in the magic folder db
-without any corresponding local file.
+with a ``size`` other than ``None``, and without any corresponding
+local file.
 
 Deletion of a directory
 ~~~~~~~~~~~~~~~~~~~~~~~