Unnecessary fetching of remote member ETags

[AutoImport-rhodey]

The logic for “Phase 2A” of SyncManager.synchronize() seems a bit off and its result goes unused:

https://github.com/rfc2822/davdroid/blob/master/src/at/bitfire/davdroid/syncadapter/SyncManager.java#L53

Assuming I’ve parsed this right, something like this should work (assuming the manualSync parameter is renamed to pullRemoteCollection)

pullRemoteCollection = pullRemoteCollection || syncResult.stats.numEntries > 0;

// PHASE 2A: check if there's a reason to do a sync with remote (= forced sync or remote CTag changed)
if (!pullRemoteCollection) {
  String remoteCTag    = remoteCollection.getCTag();
  String localCTag     = localCollection.getCTag();
  pullRemoteCollection = (remoteCTag != null && localCTag != null) && remoteCTag.equals(localCTag);
}

if (!pullRemoteCollection) {
  Log.i(TAG, "No local changes made and ctags match, will not pull from remote.");
  return;
}

Also, might have something to do with #147 ?

[AutoImport-rhodey]

Also, using != on String objects @ line 75:

https://github.com/rfc2822/davdroid/blob/master/src/at/bitfire/davdroid/syncadapter/SyncManager.java#L75

Fix…

if (localResource.getETag() == null || !localResource.getETag().equals(remoteResource.getETag())) {

I think I spotted a couple more of these while browsing through the code base. Would you prefer pull request(s) or filing issues for such small edits?

[rfc2822]

@rhodey: Seems like the return got lost in 8a651f135b95d3c534201142690ed7eed07ece85…

Issues are OK.