[chousuke]

I think committing everything in the working directory is an awful default. Few developers are disciplined enough that the contents of a working directory always make a perfect commit.

With git, how you code is a non-issue. The whole idea is that you're able to to worry about commits afterwards. The index is a wonderful tool to help you untangle the mess of code that has not yet been separated into logical pieces. Working with git is not just writing out code and then committing it. Making proper commits requires time, discipline and practice.

Part of the problem might be the mindset that a VCS is supposed to record how the development happens, but if you think about it, that does not make much sense. The actual development process of a feature or even a bugfix is often riddled with experiments, trivial mistakes, sidetracking, and other largely uninteresting issues.

Once you have thought about what is logical to record into the repository and create a commit, you can test it. Git stash allows you to put aside all other work while you run tests, and git commit --amend allows you to fix the commit until it works.

Test your commits, and you will not have broken revisions or unbisectable history.