Empty merges

[Krzysztof Nowicki]

Hi,

I'm trying to setup two Bazaar shared repositories to work similar to a
ClearCase Multisite setup. Both repositories mirror themselves, but
selected branches are owned by each of the site and mirrored read-only
on the other site. The changes from that branch is merged to the main
branch of the site. For example:

site1/
site1/dev_site1
site1/dev_site2

site2/
site2/dev_site1
site2/dev_site2

I did an initial commit to site1/dev_site1 and pushed the revision to
site2/dev_site1, then pushed site2/dev_site1 to site2/dev_site2 and
finally site2/dev_site2 to site1/dev_site2. After that I had all four
branches having the same revision and the same files. Trying to do a
merge from site1/dev_site2 to site1/dev_site1 showed that there is
nothing to do.

Next I commited a change on site1/dev_site1 and tried to propagate it.
So what I did was:
 1. pushed site1/dev_site1 -> site2/dev_site1
 2. merged site2/dev_site1 -> site2/dev_site2
 3. pushed site2/dev_site2 -> site1/dev_site1

Now I'd expect all branches to again have the same contents, however
when I tried to merge site1/dev_site2 -> site1/dev_site1 the merge
started. Although there were no file differencies the merge was
recorded. If I had this automated, the brancg site1/dev_site1 would now
be pushed to site2/dev_site1 and then the empty merge would start on the
other end. This would result in an endless loop of empty merges.

Is this an expected behaviour or some sort of bug?

Best regards
Krzysztof