The previous version of mbsync used a single channel for an entire
account. This leads to issues when trying to change the mailbox
hierarchy on the local machine. The problem with this is that some
email providers (Gmail, among others) use a slightly different maildir
hierarchy, where the standard mailboxes (Inbox, Drafts, Trash, etc.)
are stored inside another directory (`[Gmail]/` in the case of Gmail).
This new version allows the user to specify any number of groups with
any number of channels within to reorder their mail however they wish.
However, to maintain backwards compatibility, I moved the original
channel-generating code to a function that will run ONLY when
there are no groups specified for THIS account.
Typically, when a group is specified, channels will be specified as
well. However, if due to error or mistake, the user forgets to specify
ANY channels for a group, we should not generate that group's
information.
This means that no channels are specified (which maps the remote
master to local slave). In addition, the `Group <gName>` block (which
brings the separate channels together) is also not generated.
Another thing to consider is that a user might specify a group and a
channel, but perform no additional configuration of the channel.
In a configuration, this would be realized by
`accounts.email.accounts.<aName>.mbsync.groups.<gName>.channels.<cName>;`
This creates the channel with the name `<cName>` and the
`masterPattern`, `slavePattern`, and `patterns` fields use their defaults.
By definitions set within mbsync, these defaults actually specify that
the remote master's `INBOX` mail directory is synchronized to the
local slave's `INBOX` directory.
So, if there is a channel that has no fields specified, then we DO
want to generate its configuration. But if there is a group that has
no channels, then we do NOT generate it.
Changing this out is what moves us from the old system to the new one.
Instead of having a single channel manage a whole mailbox, we can now
specify an attribute set of groups that should correspond to an email
account.
Each of these groups contains an attribute set of channels that make
it up, and are grouped together for synchronization. In addition, each
of these channels can have additional IMAP4 parameters attached to
them to further refine synchronization.
Lastly, each of the channels is grouped together under the Group
section, ensuring that the channels' mailboxes synchronize as they
have been specified.
This pattern is required to either NOT be present, which means the
master pattern is used to match, or it has a list of patterns to use
beneath the master maildir to match against.
This function checks to ensure that if patterns is not empty, ONLY
then is the `Pattern` keyword printed. Otherwise, there are many, many
problems.
If there IS a list of patterns, then we use proper escaping methods to
ensure that the exact string is constructed.
This function takes in a set of groups, which includes their
consituent channels and writes the appropriate .mbsyncrc block for the
channel. The block that is generated is shown below:
Channel groupName1-channelName1
Master :<accountName>-remote:<master-pattern>
Slave :<accountName>-local:<slave-pattern>
Channel groupName2-channelName2
Master :<accountName>-remote:<master-pattern>
Slave :<accountName>-local:<slave-pattern>
Each group must have a unique name, no matter which account it is
declared under. The same holds true for channels.
Using channels with the patterns set up this way allows one to specify
which maildir directories are to be synchronized FROM the master TO
the slave. In addition, it allows for these maildirs to be remapped,
between the master server and the local slave.
This is critical, because Gmail has a strange way of storing its mail
that makes using mbsync, mu, and mu4e more difficult.
There are additional channel parameters that are already present in
this codebase from the previous use of group-channel configuration,
which will be reused.
This function takes in a set of groups, and their consituent
channels and writes the appropriate .mbsyncrc block. The block is as
shown below:
Group groupName1
Channel channelName1
Channel channelName2
Group groupName2
Channel channelName3
Each group must have a unique name, no matter which account it is
declared under. The same holds true for channels. However, if there is
a group that shares the same name as the channel, the channel will
effectively be "shadowed" by the group, and mbsync will default to
working with the group in that case.
This change makes use of the `extend` function inside `lib` to inject
a new `hm` field containing the Home Manager library functions. This
simplifies use of the Home Manager library in the modules and reduces
the risk of accidental infinite recursion.
PR #994
To allow supporting more advanced configurations. The local refers to
the "maildir store" configuration, remote to the "IMAP store", and
"channel" to the channel.
This reworks the way program specific email account options are
specified. In particular, we no longer use the deprecated `options`
field of `mkOption`. Instead submodules are used.
