[Mitgcm-support] CVS Policy

Wed Jul 9 15:56:31 EDT 2003

Alistair/ Jean-Michel / Chris / Patrick,

 The attached needs updating. You seem to have decided 
that the policy you used to have doesn't work for you.
You need to modify the attached to reflect what your policies 
are for maintaining a useful repository where you can still 
develop but that the main checkpoint branch is always a
"quality" product!!!

Thanks,

The Code Police :-)...

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         MITGCM CVS policies
         ===================

o Introduction

  This note describes policies that apply to the MITGCM CVS repository

o Why have a policy?

  CVS itself is a liberal free-for-all product that can be used in a
variety
  of ways. It is designed to provide a system for storing arbitrary
files 
  in a way that allows the change history of the individual files to be 
  tracked. If CVS is used without any other policy the result can be a 
  collection of files each of which has complex, multiply branched set
of 
  interelated versions. This sort of CVS repository can be come like a 
  library where books are simply stored in a huge heap. Although nothing
is 
  actually lost, the task of finding a coherent collection of material
soon 
  becomes impossible.

  The policies we employ address two areas 
    1. Maintaining an orderly and easily identifiable, coherent set of 
       evolving "products".
    2. Allowing concurrent, on-going development of product components.

o Development trees and checkpoint trees

  A directory within the MITGCM repository resides under either the
  development branch or the checkpoint branch. Files within each branch
  follow different policies.

o Development tree policies

  Development trees are intended to be flexible areas where arbitrary
files
  can be stored with multiple versions, many branches supporting
multiple 
  ongoing streams of development. Development trees have no policies in 
  place to control complexity. Development trees might be associated
with 
  a particular person, a certain project or a particular special piece
of 
  work. These trees are intended to be useful areas for storing current 
  work and for archiving partially finished work so that it doesn't get 
  mislaid and so that some record of the development history can be
easily 
  maintained. The only policy that applies to development trees is that 
  this style of tree is not intended to be used for providing a 
  "checkpoint" distribution. Tagged configurations of tools built from
this
  style of tree can be distributed, but because these trees do not have
any
  polcies regarding testing of functionality, platform coverage or 
  documentation these trees are not allowed to form the basis of 
  "checkpoint" distrbutions or formal "releases". Other policies can 
  be defined by individuals users of these trees but there are no
further 
  global policies. The MITGCM repository development_tree/ subdirectory
is 
  reserved for holding development trees. Development trees also serve
as 
  experimental areas for exploring new code management policies.

o Checkpoint tree policies

  Checkpoint trees are intended to provide structured storage areas for 
  holding code that is intended for open distribution and is to be
readily 
  downloaded. There are policies governing the operation of these trees 
  which are designed to ensure that distributed codes are clearly 
  identified and meet certain levels of quality.

  1. Check-out

     Just do it! Two mechanisms are available. cvsanon for read only
access
     and regular cvs co .... for read/write access.

  2. Check-in.

     The code check in procedure for a "checkpoint" tree is as follows
     2.1  Check out the latest main branch revision.
     2.2  Merge your changes into that revision.
     2.3  Build and validate new code. 
     2.4  Check that there have been no further changes to the
          repository. Repeat from 2.1 if repository has changed.
     2.5  Get clearance from other developers to check in your changes.
     2.6  Check in your changed main branch.
     2.8  Build and validate the new changes.
     2.9  Tag code as "checkpointNN". Add records to docs/tag-index.
     2.10 Build and validate test cases (see testing).
     2.11 Create and install checkpointNN.tar.gz

  3. Testing

     Things in a checkpoint tree require a test case that
     can be used to validate the component. 

  4. Checkpoint tagging

     No code should be left in limbo. Checking in code and then
     leaving it in the repository untagged is bad. When you check
     in code you are creating a new checkpoint. That means you don't
     check in some code which you "know" works 100% and then go away 
     for two weeks. When you start checking in code you make sure
     you have time to do the process end-to-end as described in section
     2.

  5. Release tagging

     Releases are only based on checkpoint tree code. Maintenance fixes
     to releases are also maintained within the checkpoint tree. Files
     within a release must have accompanying documentation. The form of
this
     documentation depends on the file type.

  6. Branches

     Branches are to be used for bug-fixes and code patches to releases 
     only. All other changes e.g. totally new features, bug-fixes to 
     checkpoints are introduced by moving checkpoint levels forward. The 
     only historical code maintenance that is employed is for fixes and 
     patches to formal releases - not checkpoints.

o These policies are causing me a big problem, what can I do?

  The policies are not enforced by any mechanism other than mutual 
  agreement! If you think the policies are not appropriate then let us
know 
  and we can discuss changing them. However, if you simply ignore the 
  policies regarding the checkpoint_release trees then your code may be 
  removed and/or your access revoked.

o What about bitkeeper

  We are looking at bitkeeper (www.bitkeeper.com). It looks cool, but 
  policies are still important. Any experience, suggestions let us know. 
  Watch this space!

Questions, comments e-mail: support at mitgcm.org
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Jean-Michel Campin wrote:
> 
> Alistair,
> 
> I discussed with Chris, and it seems better to leave thoses changes
> for the furtur. I start to put in the Cranck-Nickelson time stepping
> (in the main branch). May be after, we will see if a "developpement"
> branch is necessary.
> 
> Right now, I will check-in 3 minor corrections.
> 
> See you,
> 
> Jean-Michel