SVN commit basic policy guide

Think twice before committing

Committing something to SVN has serious consequences. All other developers will get your changes once they are in SVN, and if they break something, they will break it for everybody. All commits will be publicly available in the SVN repository forever.

The baseline is: Be aware of the consequences of your commits. Take time to think about them before committing.

Never commit code that doesn’t compile

Compile the code and correct all errors before committing. Make sure that newly added files are comitted. If they are missing your local compile will work fine but everybody else won’t be able to compile.

Run all tests and check they passed.

You certainly should make sure that the code compiles with your local setup and platform. You should also consider what consequences your commit will have for compiling on another architecture. When you made a change to database structure, commit alter scripts as well.

Test your changes before committing

Build the packages and start the application affected by your change and make sure that the changes behaves as desired.
Double check what you commit.

Do a “svn up” and a “svn diff” before committing. Take messages from SVN about conflicts, unknown files, etc. seriously. The “svn diff” will tell you exactly what you will be committing. Check if that’s really what you intended to commit.

Always add descriptive log messages

Log messages should be understandable to someone who sees only the log. They shouldn’t depend on information outside the context of the commit. Try to put the log messages only to those files which are really affected by the change described in the log message.

In particular put all important information which can’t be seen from the diff in the log message.

Don?t add email, skype or any other communication as log message.

Respect special commit policies set by the release plans

Respect the policies of the current release phase, i.e. avoid commiting new features and code shortly before a planed release.

Source control systems are not a substitute for developer communication

When you plan to make changes which affect a lot of different code in SVN, announce them on the mailing list in advance.

Changes which affect a lot of code in SVN, like making use of a new feature in the libs, might break other code even if they look trivial, e.g., because an application must also compile with older versions of the libs for some reasons. By announcing the changes in advance, developers are prepared and can express concerns before something gets broken.

Take responsibility for your commits

If your commit breaks something or has side effects on other code, take the responsibility to fix or help fix the problems.

Don’t commit code you don’t understand

Avoid things like “I don’t know why it crashes, but when I do this, it does not crash anymore.” or “I’m not completely sure if thats right, but at least it works for me.”.

If you don’t find a solution to a problem, discuss it with other developers.

Don’t abuse your SVN account to push in changes with which other developers disagree

If there are disagreements over code changes, these should be resolved by discussing them on the mailing lists or in private, not by forcing code on others by simply committing the changes to SVN.

If you commit bug fixes, consider porting the fixes to other branches

Use the same comment for both the original fix and the back port, that way it is easy to see which fixes have been backported already.

If you fix bugs reported on the bug tracking system, add the bug number to the log message

In order to keep the bug tracking system in sync with SVN, you should reference the bug report in your commits, and close the fixed bugs in the bug tracking system.

This doesn’t mean that you don’t need an understandable log message. It should be clear from the log message what has been changed without looking at the bug report.

For example: “Fixed add to basket button (#1859)”

Don’t add files generated by standard tools to the repository

Files generated at build shouldn’t be checked into the repository because this is redundant information and might cause conflicts. Only real source files should be in SVN.

Don’t use SVN keywords like Id or Log in the source files

These tags cause unnecessary conflicts when merging branches and don’t contain any information which wouldn’t be available in the SVN repository anyway.

Make “atomic” commits

SVN has the ability to commit more than one file at a time. Therefore, please commit all related changes in multiple files, even if they span over multiple directories at the same time in the same commit. This way, you ensure that SVN stays in a compilable state before and after the commit.

Don’t mix formatting changes with code changes

Changing formatting like indenting or white spaces blows up the diff, so that it is hard to find code changes if they are mixed with reinventing commits or similar things when looking at the logs and diffs later. Committing formatting changes separately solves this problem.

3 thoughts on “SVN commit basic policy guide

  1. Martin M?lek Post author

    He doesn’t want to say he is not using any source control, just not SVN. If you have time, try GIT or Mercurial. Both are more mature and has more features than SVN. After some months with both of them I like more GIT. Give it a try.

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