pull: remove inadequate use of operations records to update stepdone
The 'stepdone' set is design to be a client side mechanism. If the client used
some advanced capabilities to request necessary information (changeset,
obsmarkers, phases, etc). It marks the steps as done to avoid having a less
advanced mechanism issue a duplicated request.
So, the "stepdone.add('phases')" should be the result of a client choice,
because only the client can know it has requested all it needed to request. In
4a08cf1a2cfe this principle was broken because any phase-heads part sent by
the server to the client would declare the phases retrieval complete.
Now that there is an official phases related capability and code associated to
it. We do not need the change in
4a08cf1a2cfe anymore and we can back it out.
This brings back 'stepdone' management for 'phases' in line with the rest of
the code (including other phases handing).
Here is an example of potential misbehavior that
4a08cf1a2cfe introduced:
Imagine a server that pre-computes bundles. The bundles contains a changegroup
part and an (advisory) 'phase-heads' part. When a pull occurs, precomputed
bundled are reused if available. As the phase part is advisory it can be sent
to all clients. However they could be relevant changesets without phase
information. Either because they are already common or because they had no
precomputed bundle for them yet.
If receiving any 'phase-heads' parts disable subsequent phases re-trivial
parts, the client will not request phase data for all relevant changesets. For
example common changesets will not turn public.
pull: use 'phase-heads' to retrieve phase information
A new bundle2 capability 'phases' has been added. If 'heads' is part of the
supported value for 'phases', the server supports reading and sending 'phase-
heads' bundle2 part.
Server is now able to process a 'phases' boolean parameter to 'getbundle'. If
'True', a 'phase-heads' bundle2 part will be included in the bundle with phase
information relevant to the whole pulled set. If this method is available the
phases listkey namespace will no longer be listed.
Beside the more efficient encoding of the data, this new method will greatly
improve the phase exchange efficiency for repositories with non-served
changesets (obsolete, secret) since we'll no longer send data about the
filtered heads.
Add a new 'devel.legacy.exchange' config item to allow fallback to the old
'listkey in bundle2' method.
Reminder: the pulled set is not just the changesets bundled by the pull. It
also contains changeset selected by the "pull specification" on the client
side (eg: everything for bare pull). One of the reason why the 'pulled set' is
important is to make sure we can move -common- nodes to public.
bundle2: only grab a transaction when 'phase-heads' affect the repository
The next patch will use the 'phase-heads' part to exchange phase data relevant to
the pulled set.
'handlephases' currently acquires a transaction even in case of no-op pull,
which would results in an empty transaction and messing with the existing
journal.
Pass the transaction fetcher to updatephases so it can fetch it if necessary.