Recache folder list after creating a new folder

If we create a new folder we would previously not update our folder
list, which led to us skipping the synchronization of those new folders
during the initial run (subsequent runs would pick it up).

Invalidate the folder cache when we create a folder during folder
structure sync. Regetting the whole list from an IMAP server might be
slightly suboptimal from a performance point, but it is easy and will
lead to consistent results. Hopefully we will not have to create new
folders on each new run.

Reported-by: Daniel Shahaf <d.s@daniel.shahaf.name>
Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

Changelog.draft.rst

@@ -26,3 +26,6 @@ Bug Fixes
 * Syncing multiple accounts in single-threaded mode would fail as we try
   to "register" a thread as belonging to two accounts which was
   fatal. Make it non-fatal (it can be legitimate).
+
+* New folders on the remote would be skipped on the very sync run they
+  are created and only by synced in subsequent runs. Fixed.

offlineimap/accounts.py

@@ -265,7 +265,7 @@ class SyncableAccount(Account):
             remoterepos = self.remoterepos
             localrepos = self.localrepos
             statusrepos = self.statusrepos
-            # replicate the folderstructure from REMOTE to LOCAL
+            # replicate the folderstructure between REMOTE to LOCAL
             if not localrepos.getconfboolean('readonly', False):
                 self.ui.syncfolders(remoterepos, localrepos)
                 remoterepos.syncfoldersto(localrepos, statusrepos)

offlineimap/repository/Base.py

@@ -144,7 +144,8 @@ class BaseRepository(object, CustomConfig.ConfigHelperMixin):
         src_repo = self
         src_folders = src_repo.getfolders()
         dst_folders = dst_repo.getfolders()
-
+        # Do we need to refresh the folder list afterwards?
+        src_haschanged, dst_haschanged = False, False
         # Create hashes with the names, but convert the source folders
         # to the dest folder's sep.
         src_hash = {}
@@ -160,6 +161,7 @@ class BaseRepository(object, CustomConfig.ConfigHelperMixin):
             if src_folder.sync_this and not src_name in dst_hash:
                 try:
                     dst_repo.makefolder(src_name)
+                    dst_haschanged = True # Need to refresh list
                 except OfflineImapError, e:
                     self.ui.error(e, exc_info()[2],
                                   "Creating folder %s on repository %s" %\
@@ -203,6 +205,7 @@ class BaseRepository(object, CustomConfig.ConfigHelperMixin):
 
                 try:
                     src_repo.makefolder(newsrc_name)
+                    src_haschanged = True # Need to refresh list
                 except OfflineImapError, e:
                     self.ui.error(e, exc_info()[2],
                                   "Creating folder %s on repository %s" %\
@@ -211,7 +214,13 @@ class BaseRepository(object, CustomConfig.ConfigHelperMixin):
                 status_repo.makefolder(newsrc_name.replace(
                                 src_repo.getsep(), status_repo.getsep()))
         # Find deleted folders.
-        # We don't delete folders right now.
+        # TODO: We don't delete folders right now.
+
+        #Forget old list of cached folders so we get new ones if needed
+        if src_haschanged:
+            self.forgetfolders()
+        if dst_haschanged:
+            dst_repo.forgetfolders()
 
     def startkeepalive(self):
         """The default implementation will do nothing."""

offlineimap/repository/IMAP.py

@@ -311,6 +311,10 @@ class IMAPRepository(BaseRepository):
     def makefolder(self, foldername):
         """Create a folder on the IMAP server
 
+        This will not update the list cached in :meth:`getfolders`. You
+        will need to invoke :meth:`forgetfolders` to force new caching
+        when you are done creating folders yourself.
+
         :param foldername: Full path of the folder to be created."""
         #TODO: IMHO this existing commented out code is correct and
         #should be enabled, but this would change the behavior for

offlineimap/repository/Maildir.py

@@ -72,6 +72,10 @@ class MaildirRepository(BaseRepository):
     def makefolder(self, foldername):
         """Create new Maildir folder if necessary
 
+        This will not update the list cached in getfolders(). You will
+        need to invoke :meth:`forgetfolders` to force new caching when
+        you are done creating folders yourself.
+
         :param foldername: A relative mailbox name. The maildir will be
             created in self.root+'/'+foldername. All intermediate folder
             levels will be created if they do not exist yet. 'cur',
@@ -108,8 +112,6 @@ class MaildirRepository(BaseRepository):
                                (foldername, subdir))
                 else:
                     raise
-        # Invalidate the folder cache
-        self.folders = None
 
     def deletefolder(self, foldername):
         self.ui.warn("NOT YET IMPLEMENTED: DELETE FOLDER %s" % foldername)