This is a partial review of Practical Perforce by Laura Wingerd, published by O'Reilly (ISBN 0-596-10185-6). The reason it is partial is that I intend to comment in more detail in future blog articles on some parts of the book, and wanted to post this without waiting for the whole thing!

As Laura mentions in the preface, the book is not intended for complete beginners, but more for readers with experience in other SCM (software configuration management) tools who are looking to understand how Perforce works.

To quote the introduction, there are two parts to this book:

• Part I (Chapters 1-6) is a whirlwind technical tour of Perforce commands and concepts. It's not a tutorial, nor a reference, but helpful nonetheless.
• Part II (Chapters 7-11) describes the big picture, using Perforce in a collaborative software development environment. It is particularly strong on branching patterns, how to structure codelines and tips and tricks in this area.

The real meat of the book for most Perforce sites is thus Part II, but there are definitely some goodies in Part I.

Chapter 1 presents some fundamentals about Perforce syntax and concepts. The diagrams on pages 6 &7 explain the relationship between revisions and changelists very well.

In Chapter 2, Laura discusses client workspaces and things like view syntax. She also describes basic check outs (open for edit in Perforce command line parlance), and introduces branching when she refers to cloning of files. She includes concepts of renaming and replacing content in files, reconciling changes made offline, and even introduces a couple of bits of undocumented syntax such as "p4 files @=1452". Quite a chunk of information in this chapter.

Resolving and Merging are the subject of chapter 3 and includes some very useful diagrams showing various scenarios. If you have ever had any questions about 3-way merging in Perforce - read this! On pp68-69 she gives examples of reconciling changes you have made to a file someone else renamed using the undocumented merge3 command - interesting if a touch esoteric (also referred to in "How to undo a merge" on p80. The recommendation on p74 to sync and resolve one changelist at a time is certainly worth considering, although I think it will depend on your environment as to how necessary that is.

The basics of branching are covered in chapter 4 including initial scenarios and how to track merge requirements across branches. She makes quite a lot of use of the interchanges command (not yet exposed in the GUIs) and explains the gory details of "yours", "theirs" and "base" nicely. Her approach of using filespec integrations for the initial examples is nice and simple, but I suspect more people are likely to use branch specs in real life. On p111 she gives a useful couple of commands to show how to find which changes have been merged in (more likely to be automated in scripts for most sites I would expect). Other subjects ocvered include all the gory details of what integrate actually does, as well as some very useful details as to what the interchanges command can tell us, particular with respect to cherry picked integrations.

Chapter 5 is quite short on labels and jobs and shows all the basics. A quick note on the final section where a job is used as a reference for a changelist - as of release 2005.2 there is an undocumented "dynamic label" option where a label can have an attached revision which probably makes the job trick unnecessary.

Chapter 6 gets into the subject of remote depots and proxies and also mentions the very useful spec depot option (automatic versioning of all spec objects). There is also some good advice on using p4web in browse mode to access your repository. The section on triggers and automation is a little light, but understandable.

Part II starts with Chapter 7 "How software evolves". This chapter is perhaps the highlight of the book, and introduces concepts that are totally independent of Perforce and apply to many SCM tools. Fortunately the chapter is currently available as a free PDF document from the O'Reilly website for the book. A firm understanding of the concepts introduced here will make it much easier for you to come up with suitable branching patterns for use in your organisations, and also, perhaps more importantly, give you some incredibly useful concepts for explaining your structure to other people within the organisation. Most SCM problems are due to poor communication rather than poor tools, or poor ideas. Laura relates the problems in the real world prevent us from an overly simplistic ideal world, and yet how some simple concepts allow us to manage this real world complexity. The "flow of change" and the "tofu scale" are classic concepts which should be in everyone's SCM vocabulary.

Summary

I am going to stop this post here, and will get to further chapters and some detailed comments on them as I have time.

But I will finish with the recommendation - buy this book!!