On Versions

Versions are dead, long live versions

What version of Chrome are you using? Beyond the major version number, what version of your operating system are you on? If you deploy using Linux code, what version is your Linux Kernel?

My answer to those questions: I don’t know. Or didn’t. I just checked and I’m on version 42.0.2311.39 beta for Chrome, 10.10.2 for OS X, and 3.16.7-tinycore64 for my Docker VM I use for testing images. My life isn’t better for knowing that information, though.

The same is true for most of the software you create. The version number doesn’t matter, but to this day software developers don’t want to mark their software as version 1.0. 1.0 carries a lot of weight. To a lot of developer’s it means you’re done. It means you’re confident in it. It means things aren’t going to drastically change.

The Python community is afraid of 1.0. The only reason I can understand why is because it’s the largest case of collective imposter’s syndrome I’ve ever seen.

Don’t believe me? There are 61,564 Python packages that have been released according to this page. Of those, 40,489 have a version number that begins with 0. That’s two-thirds of the packages that I can’t tell anything from those version numbers.

For example, is virtual-touchpad more stable than Werkzeug? The former is at version 0.11 while the latter is only at 0.10.1. Of course, Werkzeug is almost certainly more stable. The download numbers seem to tell me that with it’s more than 20,000 downloads in the last day. Werkzeug runs a huge chunk of the web that’s powered by Python. Flask doesn’t exist without it.

Statements like the one in the previous paragraph that begin with “of course”, however, are only obvious with the correct reference. If you’re coming from world outside of the Python community, you don’t have that reference.

Sane Versions

Enter Sematic Versions. It can be described in a tweet, but here’s the slightly more expanded version.

  • Versions begin at 0.x. Anything in 0.x hasn’t been deployed anywhere and you’re still turning it into something useful. You make no guarantees about it.
  • The first code that’s used in production is 1.0.0. Production means it’s being used and not just written.
  • Versions follow Major.Minor.Bugfix.
  • Major version numbers are for backward compatibility. If this number changes, the API has changed and it means that code written against the old version won’t work with the new version in at least one case.
  • Minor versions are for new features. Nothing should break between versions 1.0.0 and 1.1.0 or 1.101.0.
  • Bugfix versions are for bugfixes. No new features are added here, just corrections to code to make sure it does what it’s supposed to.

It’s really that simple. When I install your software package at version 1.2.0 I know that I can run anything before version 2.0.0 and it should all continue to work.

There are some devils hiding in the details. For example, how many back versions do you support? If you find a bug in version 1.3.0 that was present all the way back to 1.0.0, do you patch versions 1.0.x, 1.1.x, and 1.2.x as well? Does each new feature mean a minor version bump?

That’s up to you as a maintainer. There are no right answers to those questions: the main point is to make sure that code that works in one release doesn’t break in the next. If it does, and sometimes it needs to, bump the major version number.

Also, it’s ok to break. SemVer gives you the opportunity to convey to the users of your code that something needed change in ways that weren’t compatible with the previous code.

To the Python Community

Please consider adopting SemVer. What’s stopping you? Is it because you don’t think your code is ready to be called 1.0? I promise you, it is. It’s actually awesome!

All I want is for you to quit worrying about getting it perfect. Get it close to right, make it so people can use it. Then release it. If you get something wrong or need to fundamentally change the API, do it, but bump the major version number so everyone knows at what point their code might not just work™.

Software is just that: soft. It can, and should change. Don’t be afraid of v1.0 or v2.0 or v20.0.

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