ARMDeveloperEnvironment

Revision 9 as of 2010-05-19 19:04:37

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Summary

  • provide a way to create new archives by branching a subset of ubuntu packages
  • make it easy to change these archives
  • visualize (through a web tool, probably) deltas between archives and their (direct or no?) upstreams/downstreams
  • manage these deltas by pulling/pushing changes from/to upstreams

Not sure if the distinction between full/slim archives is pertinent here? I mean, what type of archives would we be creating? AIUI, we need to create a full archive when the downstream archive includes toolchain changes that would break binary compatibility?

Release Note

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Rationale

We need to allow ARM developers to easily create/maintain derivative archives for use during the development of new devices. They should be able to branch archives, make changes to them and manage deltas.

User stories

  • Ted wants to package the latest version of the Foo project, which depends on the latest version of Bar and Baz, which in turn are not yet available in Ubuntu. Instead of packaging Bar and Baz, Joe can branch off of two existing PPAs that already have packages for the latest version of Bar and Baz. (This use case was invented to try and explain why we might want multiple parents, as discussed during the UDS session)
  • A partner is developing a custom netbook UI but need to keep it private until it's finalized, so they create a slim archive off of the main Ubuntu archive and do any UI changes (or add new packages) on their new archive, which is only accessible by themselves. The slim archive is made possible (instead of a full one) because it should be binary compatible with the main Ubuntu archive. (Not yet clear whether or not the new archive should be hosted on LP, like a private PPA; probably need to allow it to live in LP or outside)
  • YAP (Yet Another Partner) is working on optimizing their new (not-yet-released) chip, but for that they need a version of GCC newer than the one on the Ubuntu archive. They want to create a new (private) archive where they'll upload the new GCC version, but upgrading to that new version of GCC is known to break binary compatibility, so it must be possible for them to easily rebuild all packages using the new GCC.
  • YAP also has a separate team working on the UI for a device which will use their new chip, so they want to have yet another archive, based on the one containing the new GCC, where they'll make their UI changes without affecting other users of the archive containing the new GCC.
  • During the development of YAP's latest device, it should be possible for them to easily see the changes done to the upstream archive since both archives diverged. They should also be able to review those changes and pull the ones they want into their archive.
  • YAP has finished development of a new device and want to upstream the changes they've done when developing. They need to first see what are those changes, decide which ones should go upstream and submit them.

Is https://wiki.ubuntu.com/Specs/M/DerivedArchiveRebuild related to this in any way?

Assumptions

  • archives can be refered to by their URLs. (I think this is how we're going to tell the tools the archives they'll operate on)

Design

You can have subsections that better describe specific parts of the issue.

Implementation

This section should describe a plan of action (the "how") to implement the changes discussed. Could include subsections like:

UI Changes

Should cover changes required to the UI, or specific UI that is required to implement this

Code Changes

Code changes should include an overview of what needs to change, and in some cases even the specific details.

Test/Demo Plan

It's important that we are able to test new features, and demonstrate them to users. Use this section to describe a short plan that anybody can follow that demonstrates the feature is working. This can then be used during testing, and to show off after release. Please add an entry to http://testcases.qa.ubuntu.com/Coverage/NewFeatures for tracking test coverage.

This need not be added or completed until the specification is nearing beta.

Unresolved issues

This should highlight any issues that should be addressed in further specifications, and not problems with the specification itself; since any specification with problems cannot be approved.

BoF agenda and discussion

Goals

  • Goal: branch subset of ubuntu packages and manage changes
    • experiments - short/adhoc / long running (- Salgado: what does this mean?)
    • hierarchy: common archive -> project archive -> project variant archive etc.

      • automatic superseding and merging (- Salgado: what does this mean?)

Releasing

  • Release/Freezes/ACLs
    • have automatic merged release branch owned by releaes team during development
      • period that gets set to manual mode during freezes.
    • at release another branch is auto created that is not changeable??
    (- Salgado: not sure what any of the above means either)

Getting Started

  • getting started: command line tool to branch some archive; by default it starts
    • by copying the binaries; (- Salgado: what if we know the archive will have a new toolchain which breaks binary compatibility? would it make sense to force a rebuild at that point?)
  • some changes like gcc would require move a binary copy archive to a source/rebuild
    • everything mode? is that true? gcc might just have changed for a bug fix/crash etc.
    • tracking build dependencies may be relevant here
    (- Salgado: does this means we'll be aiming to start with slim archives and turn them into full archives if/when there's a toolchain change that breaks binary compatibility?)
  • a way of enforcing version number rules in a particular archive would be good (-Salgado: don't know what this means either)


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