BundleFormat2

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
• pull:
  • (mostly for phase)
    • and any other data the server send as a reply to the multipart-bundle The server would be able to reply a multi-bundle. To inform the client of potential phase//bookmark//changeset rewrites etc…

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.

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