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| 8 |  | 
| 9 | <h2> | 
| 10 | Introduction</h2> | 
| 11 | This note describes policies that apply to the MITGCM CVS repository. | 
| 12 | <h2> | 
| 13 | Why have a policy?</h2> | 
| 14 | CVS itself is a liberal free-for-all product that can be used in a variety | 
| 15 | of ways. It is designed to provide a system for storing arbitrary files | 
| 16 | in a way that allows the change history of the individual files to be tracked. | 
| 17 | If CVS is used without any other policy the result can be a collection | 
| 18 | of files each of which has complex, multiply branched set of interelated | 
| 19 | versions. This sort of CVS repository can be come like a library where | 
| 20 | books are simply stored in a huge heap. Although nothing is actually lost, | 
| 21 | the task of finding a coherent collection of material soon becomes impossible. | 
| 22 | <p>The policies we employ address two areas | 
| 23 | <ol> | 
| 24 | <li> | 
| 25 | Maintaining an orderly and easily identifiable, coherent set of evolving | 
| 26 | "products".</li> | 
| 27 |  | 
| 28 | <li> | 
| 29 | Allowing concurrent, on-going development of product components.</li> | 
| 30 | </ol> | 
| 31 |  | 
| 32 | <h2> | 
| 33 | Development trees and checkpoint trees</h2> | 
| 34 | A directory within the MITGCM repository resides under either the development | 
| 35 | branch or the checkpoint branch. Files within each branch follow different | 
| 36 | policies. | 
| 37 | <h2> | 
| 38 | Development tree policies</h2> | 
| 39 | Development trees are intended to be flexible areas where arbitrary files | 
| 40 | can be stored with multiple versions, many branches supporting multiple | 
| 41 | ongoing streams of development. Development trees have no policies in place | 
| 42 | to control complexity. Development trees might be associated with a particular | 
| 43 | person, a certain project or a particular special piece of work. These | 
| 44 | trees are intended to be useful areas for storing current work and for | 
| 45 | archiving partially finished work so that it doesn't get mislaid and so | 
| 46 | that some record of the development history can be easily maintained. The | 
| 47 | only policy that applies to development trees is that this style of tree | 
| 48 | is not intended to be used for providing a "checkpoint" distribution. Tagged | 
| 49 | configurations of tools built from this style of tree can be distributed, | 
| 50 | but because these trees do not have any polcies regarding testing of functionality, | 
| 51 | platform coverage or documentation these trees are not allowed to form | 
| 52 | the basis of "checkpoint" distrbutions or formal "releases". Other policies | 
| 53 | can be defined by individuals users of these trees but there are no further | 
| 54 | global policies. The MITGCM repository development_tree/ subdirectory is | 
| 55 | reserved for holding development trees. Development trees also serve as | 
| 56 | experimental areas for exploring new code management policies. | 
| 57 | <h2> | 
| 58 | Checkpoint tree policies</h2> | 
| 59 | Checkpoint trees are intended to provide structured storage areas for holding | 
| 60 | code that is intended for open distribution and is to be readily downloaded. | 
| 61 | There are policies governing the operation of these trees which are designed | 
| 62 | to ensure that distributed codes are early identified and meet certain | 
| 63 | levels of quality. | 
| 64 | <ol> | 
| 65 | <li> | 
| 66 | Check-out</li> | 
| 67 |  | 
| 68 | <br>Just do it! Two mechanisms are available. cvsanon for read only access | 
| 69 | and regular cvs co .... for read/write access. | 
| 70 | <li> | 
| 71 | Check-in</li> | 
| 72 |  | 
| 73 | <br>The code check in procedure for a "checkpoint" tree is as follows | 
| 74 | <ol> | 
| 75 | <li> | 
| 76 | Check out the latest main branch revision.</li> | 
| 77 |  | 
| 78 | <li> | 
| 79 | Merge your changes into that revision.</li> | 
| 80 |  | 
| 81 | <li> | 
| 82 | Build and validate new code.</li> | 
| 83 |  | 
| 84 | <li> | 
| 85 | Check that there have been no further changes to the repository. Repeat | 
| 86 | from 2.1 if repository has changed.</li> | 
| 87 |  | 
| 88 | <li> | 
| 89 | Get clearance from other developers to check in your changes.</li> | 
| 90 |  | 
| 91 | <li> | 
| 92 | Check in your changed main branch.</li> | 
| 93 |  | 
| 94 | <li> | 
| 95 | Build and validate the new changes.</li> | 
| 96 |  | 
| 97 | <li> | 
| 98 | Tag code as "checkpointNN". Add records to docs/tag-index.</li> | 
| 99 |  | 
| 100 | <li> | 
| 101 | Build and validate test cases (see testing).</li> | 
| 102 |  | 
| 103 | <li> | 
| 104 | Create and install checkpointNN.tar.gz</li> | 
| 105 | </ol> | 
| 106 |  | 
| 107 | <li> | 
| 108 | Testing</li> | 
| 109 |  | 
| 110 | <br>Things in a checkpoint tree require a test case that can be used to | 
| 111 | validate the component. | 
| 112 | <li> | 
| 113 | Checkpoint tagging</li> | 
| 114 |  | 
| 115 | <br>No code should be left in limbo. Checking in code and then leaving | 
| 116 | it in the repository untagged is bad. When you check in code you are creating | 
| 117 | a new checkpoint. That means you don't check in some code which you "know" | 
| 118 | works 100% and then go away for two weeks. When you start checking in code | 
| 119 | you make sure you have time to do the process end-to-end as described in | 
| 120 | section 2. | 
| 121 | <li> | 
| 122 | Release tagging</li> | 
| 123 |  | 
| 124 | <br>Releases are only based on checkpoint tree code. Maintenance fixes | 
| 125 | to releases are also maintained within the checkpoint tree. Files within | 
| 126 | a release must have accompanying documentation. The form of this documentation | 
| 127 | depends on the file type. | 
| 128 | <li> | 
| 129 | Branches</li> | 
| 130 |  | 
| 131 | <br>Branches are to be used for bug-fixes and code patches to releases | 
| 132 | only. All other changes e.g. totally new features, bug-fixes to checkpoints | 
| 133 | are introduced by moving checkpoint levels forward. The only historical | 
| 134 | code maintenance that is employed is for fixes and patches to formal releases | 
| 135 | - not checkpoints.</ol> | 
| 136 |  | 
| 137 | <h2> | 
| 138 | These policies are causing me a big problem, what can I do?</h2> | 
| 139 | The policies are not enforced by any mechanism other than mutual agreement! | 
| 140 | If you think the policies are not appropriate then let us know and we can | 
| 141 | discuss changing them. However, if you simply ignore the policies regarding | 
| 142 | the checkpoint_release trees then your code may be removed and/or your | 
| 143 | access revoked. | 
| 144 | <h2> | 
| 145 | What about bitkeeper</h2> | 
| 146 | We are looking at bitkeeper (www.bitkeeper.com). It looks cool, but policies | 
| 147 | are still important. Any experience, suggestions let us know. Watch this | 
| 148 | space! | 
| 149 | <p>Questions, comments e-mail: code.czars@mitgcm.org | 
| 150 | <br> | 
| 151 | <hr WIDTH="100%"> | 
| 152 | <table CELLSPACING=0 CELLPADDING=0 WIDTH="100%" NOSAVE > | 
| 153 | <tr NOSAVE> | 
| 154 | <td><font size=-1>Last modified on $Date: $</font></td> | 
| 155 |  | 
| 156 | <td> | 
| 157 | <div align=right><font size=-1>CVS: $Source: $Revision: $</font></div> | 
| 158 | </td> | 
| 159 | </tr> | 
| 160 | </table> | 
| 161 |  | 
| 162 | </body> | 
| 163 | </html> |