use replay rather than do_update

Any chance you could give any pointers on
  a) how the current code works
  b) how this would need to work?

We do an update request for each revision at the moment specifying that we have the parent revision completely to the reporter. The alternative would be to use replay for each revision, but that means we need to be able to access any old revisions contents, and that's not always the case. E.g. something that had the same name could be in a different branch.

You can try out the replay functionality by removing " and False" from line 1074 in fetch.py.

Actually, commenting out that " and False" and the one on the previous line doesn't seem to cause any test failures right now ...

... on the other hand, I have yet to see it alter the SVN requests made across the net :-(

Are you sure? I get plenty of test failures with that commented out:

/usr/bin/python ./setup.py build_ext --inplace
running build_ext
BZR_PLUGIN_PATH=/home/jelmer/bzr-svn/0.6/.plugins: /usr/bin/python /usr/bin/bzr selftest --starting-with=bzrlib.plugins.svn
testing: /usr/bin/bzrg
   /usr/lib/python2.5/site-packages/bzrlib (1.17 python2.5.4)

ERROR: bzrlib.plugins.svn.tests.test_branch.WorkingSubversionBranch.test_fetch_branch
    ("Invalid revision number '-1'", 160006)

ERROR: bzrlib.plugins.svn.tests.test_branch.WorkingSubversionBranch.test_fetch_dir_upgrade
    An inconsistent delta was supplied involving 'bla', '2@9d440acb-58e9-4928-80c6-6768b86833c7:branches%2Fabranch%2Fbla'
reason: Path already versioned

ERROR: bzrlib.plugins.svn.tests.test_branch.WorkingSubversionBranch.test_fetch_odd
    An inconsistent delta was supplied involving 'hosts', '5@06ffe7b4-8f88-473c-9a9b-3132f52b928e:branches%2Ffoobranch%2Fhosts'
reason: Path already versioned

ERROR: bzrlib.plugins.svn.tests.test_branch.WorkingSubversionBranch.test_fetch_replace
    An inconsistent delta was supplied involving 'hosts', '5@6f95bc5c-e18d-4021-aca8-49ed51dbcb75:branches%2Ffoobranch%2Fhosts'
reason: Path already versioned

ERROR: bzrlib.plugins.svn.tests.test_branch.WorkingSubversionBranch.test_ghost_workingtree
    ("Invalid revision number '-1'", 160006)

^Cbzr: interrupted

Hmm. Doh! I got mixed up between commenting in and commenting out!

Whoops!

... at least now I have something to debug ;-).

You might want to also have a look at lp:~jelmer/bzr-svn/replay, which contains my initial work on this.