Code review comment for lp:~spiv/bzr/inventory-delta

I'm not really sure what testing you've done on this, but I'm getting some really strange results.

Specifically, when I push it turns out to be sending xml fragments over the wire. Specifically it seems to be this code:
        elif (not from_format.supports_chks):
            # Source repository doesn't support chks. So we can transmit the
            # inventories 'as-is' and either they are just accepted on the
            # target, or the Sink will properly convert it.
            # (XXX: this assumes that all non-chk formats are understood as-is
            # by any Sink, but that presumably isn't true for foreign repo
            # formats added by bzr-svn etc?)
            return self._get_simple_inventory_stream(revision_ids,
                    missing=missing)

Which means that the raw xml bytes are being transmitted, and then the target side is extracting the xml upcasting and downcasting.

I see that there are code paths in place to do otherwise, but as near as I can tell, "_stream_invs_as_deltas" is only getting called if the *source* format is CHK.

From the profiling I've done, the _generate_root_texts() code is the bulk of the overhead with the new format. But *that* is because all of the data is sent to the server as XML texts, and the server has to do all the work to convert it.

When I just disable the code path that sends 'simple_inventory_stream', then I get:

$ time wbzr push bzr://localhost/test-2a/x
bzr: ERROR: Version present for / in TREE_ROOT

So I have a *strong* feeling the code you've introduced is actually broken, and you just didn't realize it.