[Bug 299417] New: Incorrect local Maildir handling

[Ivan Adzhubey]

https://bugs.kde.org/show_bug.cgi?id=299417

            Bug ID: 299417
          Severity: critical
           Version: unspecified
          Priority: NOR
          Assignee: kdepim-bugs at kde.org
           Summary: Incorrect local Maildir handling
    Classification: Unclassified
                OS: Linux
          Reporter: iadzhubey at verizon.net
          Hardware: Ubuntu Packages
            Status: UNCONFIRMED
         Component: commands and actions
           Product: kmail2

Hi,

I have noticed a number of bugs in the way Kmail2 (SC 4.8.2/4.8.3) handles
local mail:

1.When copying or moving messages from one folder (remote or local) to another
local folder, messages are initially placed into "new" subdirectory in the
corresponding Maildir folder, regardless of the source message real status
(e.g. even if messages are marked as read). Messages should go to "cur"
subfolder instead.

2.Message files stored in "new" subfolder after copy/move operation lack any
Maildir suffixes, e.g. ":2,S". I assume that the combination of bugs 1&2 is
what causes infamous "unreadable messages" bug when clicking on a message
header does not display it's text. This may happen due to race condition, see
below.

3.Clicking on a newly copied message initiates the following process in the
backgound: a) message file is moved from "new" to "cur" subfolder and b)
message file is renamed by appending correct ":2,S" suffix to it. This process
is ***extremely*** slow and is done in two steps (first move, then rename). In
addition, there is absolutely no progress indication in the GUI or any
notification whatsoever. This creates a major race condition and critical
failure risk point. Because this operation is a) very slow, b)
non-transactional (completed in at least two steps) and c) does not notify user
of critical background operation in progress, a user would proceed working with
folders as usual, e.g. clicking on message headers, attempt to further
move/copy messages to another folders or delete them, etc. This would quickly
exhaust backend capabilities (akonadi?) to manage file transactions and at some
point provoke a crash due to race condition, leaving Maildir tree in
unpredictable state and possibly corrupting akonadi database. After that, local
mail folders structure becomes completely unaccessible through GUI.

4.A workaround for bugs 1&2 which prevents bug 3 from stricking is to do the
follwoing immediately after copying/moving messages between folders in GUI: a)
select all messages in the target folder (Ctrl-A), b) mark all messages as
Unread (Ctrl-U), c) mark folder as read via its context menu, d) wait until all
file operations in Maildir folders described in (3) are completed, tracking
progess by watching actual status of the corresponding local Maildir folders
(i.e. under ~/.local/share/loacl-mail). The latter may take a long time, up to
48 hours for a copy operation on a folder worth 90,000 messages (Core i7 3GHz,
6GB RAM, 10Krpm drive). If the operation is iterrupted before completion (e.g.
by shutting down computer) your local folders will be rendered unusable and you
will have to start from scratch.

5.An additional unrelated bug: neither Ctrl-A shortcut nor Edit->Select->All
can select all messages in a folder with the message threading enabled and at
least some message threads collapsed. You need to uncollapse all threads before
issuing "select all" otherwise a number of messages will be randomly left out.


Reproducible: Always




Tested with Kubuntu Desktop 12.04 (x86_64) & KDE SC 4.8.2, reproduced after
updating to SC 4.8.3.

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