Leopard migration plansEdit

Created , updated

This page provides a broad overview of my product roadmaps and the development infrastructure that I plan to use in the move to Mac OS X Leopard.

Timeline

The official Apple web page says that Leopard is, "Coming spring 2007", which means at some point in March, April or May 2007. At the time of writing (late September 2006) that means I have a minimum of 5 months, and possibly as much as 7 months, in which to make my products Leopard-ready.

My plan in that timeframe is to continue releasing updates for my products without changing their minimum system requirements:

But once Leopard is out I plan to raise the minimum requirements to take advantage of the new features. Development will be split into two branches: new releases (the main branch) will require Leopard; releases on the other branch (maintenance branch) will continue to support the older versions of Mac OS X but will be basic bug fix and maintenance releases only.

The only exception to this pattern will be Install, which will continue to run on any version of Mac OS X from Jaguar up; there will be no branching for Install.

In previous Mac OS X updates I have held back from increasing the minimum system requirements and this has lead to some unfortunate limitations. It means that an application like Synergy, which has always supported Jaguar as a minimum, has been unable to take advantage of newer technologies introduced in Panther like Cocoa Bindings and this has made development more difficult. Likewise, Synergy Advance, which has always supported Panther as a minimum, has been unable to take advantage of newer technologies introduced in Tiger like Core Data. (Note: this is somewhat of a simplification as it is possible to partially support newer-technologies by using tricks like selective bundle loading and weak linking, but these tricks tend to make things more complex and difficult to maintain.)

Leopard offers some fantastic new APIs and I changes to the Objective-C language such as garbage collection so I’m going to use it as the point for the "big jump" in which I move all main development to the new platform. This will enable me to make some big changes, introduce more new features, and work better and faster. To support customers using older versions of the operating system I’ll continue to release maintenance releases for those systems. Also, from a business perspective this makes sense; by offering products to a wider market segment I stand to sell more licenses.

To the customer the releases will look like this:

  • Consider a product with versions 1.0, 1.2, 1.3 that runs on Panther and up.
  • Once Leopard is out, most development will occur on a new branch — the 2.0, 2.1, 2.2 (etc) releases — and these releases will only run on Leopard.
  • I will continue to do maintenance releases on the old branch (1.3.1, 1.3.2, 1.4 etc) that support the old version of Mac OS X.

Phase 1: Jaguar/Panther compatible releases

In the 5 to 7 months that remain before Leopard comes out I will continue targeting the older versions of Mac OS X and performing public releases where appropriate.

Phase 2: Branching for Leopard

When I am ready to start Leopard-specific development I will perform a branch. The page, Creating branches with Subversion, details how I did this for the Synergy code base. For the time being I am doing my work directly on the panther branch. Most likely after the next public release I will merge the changes from that branch onto the trunk and start doing most of the work on trunk instead.

During this transition period I will continue to use the Panther version of buildtools. When the focus shifts to Leopard I will branch buildtools and all of my frameworks at the same time. The Leopard-oriented development (occurring in the trunk of each product) will continue as normal, but the development for older versions will need to use the older versions of buildtools. The easiest way to achieve this will be to have multiple, totally separate build hierarchies:

# Leopard development (trunk)
work/build
work/build-intermediates
work/buildtools
work/project1
work/project2
work/framework1
work/framework2

# Tiger branch, likewise for Panther, Jaguar
work-tiger/build
work-tiger/build-intermediates
work-tiger/buildtools
work-tiger/project1
work-tiger/project2
work-tiger/framework1
work-tiger/framework2

Phase 3: Leopard releases

In general, all new features will go into the trunk branch (for Leopard) and only bug fixes and maintenance changes will go into the older branches.