Differences between revisions 17 and 18
Revision 17 as of 2014-03-10 22:38:51
Size: 4887
Comment:
Revision 18 as of 2014-03-11 20:15:21
Size: 4892
Comment:
Deletions are marked like this. Additions are marked like this.
Line 114: Line 114:
* HG10 (old changeset bundle format)
* HG19 (new changeset bundle with support for modern stuff)
* pushkey data (phase, bookmarks)
* obsolescence markers (format 1 and upcoming format 2 ?)
* client capacity (to be used for the reply multi part bundle)
 * HG10 (old changeset bundle format)
 * HG19 (new changeset bundle with support for modern stuff)
 * pushkey data (phase, bookmarks)
 * obsolescence markers (format 1 and upcoming format 2 ?)
 * client capacity (to be used for the reply multi part bundle)

Note:

This page is primarily intended for developers of Mercurial.

This page describes the current plan to get a more modern and complete bundle format. (for old content of this page check BundleFormatHG19)

(current content is copy pasted from 2.9 sprint note)

New bundle format

  • lightweight
  • new manifest
  • general delta
  • bookmarks
  • phase boundaries
  • obsolete markers
  • >sha1 support

  • pushkey
  • extensible for new features (required and optional)
  • progress information
  • resumable?
  • transaction commit markers?

It's possible to envision a format that sends a change, its manifest, and filenodes in each chunk rather than sending all changesets, then all manifests, etc. capabilities

Changes in current command

Push Orchestraction

Current situation
  • push:
    • changesets:
      • discovery
      • validation
      • actual push
    • phase:
      • discovery
      • pull
      • push
    • obsolescence
      • discovery
      • push
    • bookmark
      • discovery
      • push

Aimed orchestration

* push:

  • discovery:
    • changesets
    • phase
    • obs
    • bookmark
  • post-discovery action:
    • current usecase move phase for common changeset seen as public.
  • local-validation:
    • (much easier will everything in hands)
    • complains about:
      • multiple heads
      • new branch
      • troubles changeset
      • divergent bookmark
      • Rent in Manhattan
      • etc…
  • push:
    • (using multipart-bundle when possible)
      • The one and single remote side transaction happen here
  • (post-push) pull:
    • The server send back its own multipart-bundle to the client
      • (The server would be able to reply a multi-bundle. To inform the client of potential phase//bookmark//changeset rewrites etc…)

post-push pull

If we lets the protocol send arbitrary data to the server, we need the server to be able to send back arbitrary data too.

The idea is to use the very same top level format. It could contains any kind of thing the client have advertise to understand. This last phase is advisory this the client can totally decide to ignores its content.

Possible use case are:

  • sending standard output back
  • sending standard error back
  • notification that a changeset was made public on push
  • notification of partially accepted changeset
  • notification of automatic bookmark move on the server
  • test case result (or test run key)
  • Automatic shipment of Pony to contributor address
  • … (Possibility are endless)

Changes in Pull

Same kind of stuff wil happen but pull is much simpler. (I'm not worried at all about it)

Change in Bundle/Unbundle

Unbundle would learn to unbundle both

Maybe we can have the new bundle format start with an invalide entry to prevent old unbundle to try to import them

bundle should be able to produce new bundle. It can probably not do it by default for a long time however :-/

Top level Bundle

content

On the remote side, the server will need to redo the validation that was done on the remote side to ensure that nothing interesting happened between discovery and push. We need to send appriopricate data to the remote for validation. This implies either argument in the command data. Or a dedicated section in the bundle. The dedicated section seems the way to go as it feels more flexible. We do not know what kind of data will be monitored and send. So we cannot build a sensible set of argument doing the job. With a dedicated section in the multi-part bundle, we can make this section evolve over time to match the evolution of data we send to the server.

forseen sections

Here are the idea we already have about section

  • HG10 (old changeset bundle format)
  • HG19 (new changeset bundle with support for modern stuff)
  • pushkey data (phase, bookmarks)
  • obsolescence markers (format 1 and upcoming format 2 ?)
  • client capacity (to be used for the reply multi part bundle)

Changesets exchange

New header

type Header struct {
    length       uint32
    lNode        byte
    node         [lNode]byte

    // if empty (lP1 ==0) then default to previous node in the stream
    lP1          byte
    p1           [lP1]byte

    // if empty, nullrev
    lP2          byte
    p2           [lP2]byte

    // if empty, self (for changelogs)
    lLinknode    byte
    linknode     [lLinknode]byte

    // if empty, p1
    lDeltaParent byte
    deltaParent  [lDeltaParent]byte 
}

We'll modify the existing changegroup type so it can pretend to be a new changegroup that just has a variety of empty fields. Progress information fields might be optional.


CategoryNewFeatures

BundleFormat2 (last edited 2018-02-10 00:05:58 by AviKelman)