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Modular Software and Version Control

 

There are many issues to consider when deciding how to structure your software from an architectural point of view. Chances are that you’ve already split up your code into several modules or components to separate the various routines.

However, deciding about the best software design isn’t the purpose of this blog. At PureCM, we like to look at software from a version control point of view. So let’s agree for the purpose of this blog that a component is a set of files and folders that are versioned together. This also means we’re looking at code components, and at referencing compiled DLLs or the like.

To modularise or not to modularise…

Remember, we’re looking at this question from a version control point of view. So basically there are two options: consider project as one module, or having many modules that are developed individually.

The advantage of having one module for the whole project is obvious. The project gets always built and versioned as a whole, while release snapshots are also taken from version branches as a whole. Also, creating a workspace for a version or feature would always populate the developer workspace with the full content:

Simple. So why would we want to have separate modules?

One of the main reasons is that you might want to reuse certain modules or components for other projects, that they might suddenly get their dedicated developer (team) and individual release cycles. As a consequence, these components need their own container in order to version them separately from the projects they are linked to.

Shared components – an example

Let’s assume you’re using your icon component across multiple projects, with only a specific group working on them – I’ll call them ‘magic designers’. They are the only ones working on these files, so don’t really need to get the other project content to make their changes.

In such a case, you can give them their own version branch in PureCM, which only contains the ‘icons’ components files and folders. Any of your projects using that component could then link to that component version.

So now your developers can either create a workspace for the relevant project version/feature, or the shared component only.

 

Sharing component releases or all changes immediately?

Using shared components in PureCM also gives you another option. You can choose whether you want to share a static component release or dynamic component version.

The obvious advantage of sharing component releases is that changes made against the component version aren’t shared until t ested and ‘released’ as a release snapshot. A development manager would then simply update the component link to the latest component release to update his project. Of course, this also assures that you can link your projects to different component versions as needs dictate.

O n the other hand, there are cases when you’d want to immediately reflect changes made to a component across all linked location. Linking to the component version allows you to do so. Of course, even with this solution you can have your ‘magic designers’ group work on multiple component versions without problems.

Summary

Which of the discussed option you choose is down to your needs; the following t able summarises the available options in PureCM:

 

Only share stable component updates

Share component updates immediately

Support one component version only

Link to relevant component release

Link to component version

Support multiple component versions

Link to component release of the relevant version

Link to relevant component version


However, as a development manager you can be sure that PureCM tracks all your changes across all linked locations:  any changes made to the component, when a component was linked to which project, at what point the link was updated to a newer component release etc.

If you work with PureCM Professional and use tasks, you will get even more information. PureCM will show all tasks originally completed against a component in the history view of any linked location - and the other way around. Not bad to facilitate release note creation (and have a full, repository-wide task history)!

If you want to learn more about working with shared components, there’s also a white paper available. It covers the above and component setup in more detail. Just download it from here:

http://www.purecm.com/download_file.php?type=white_paper&download_id=7