How Working Copies Track the Repository
For each file in a working directory, Subversion records two essential pieces of information in the .svn/ administrative area:
Which revision your working file is based on (this is called the file’s working revision)
A timestamp recording when the local copy was last updated by the repository
Given this information, by talking to the repository, Subversion can tell which of the following four states a working file is in:
- Unchanged, and current
The file is unchanged in the working directory, and no changes to that file have been committed to the repository since its working revision. An svn commit of the file will do nothing, and an svn update of the file will do nothing.
- Locally changed, and current
The file has been changed in the working directory, and no changes to that file have been committed to the repository since you last updated. There are local changes that have not been committed to the repository; thus an svn commit of the file will succeed in publishing your changes, and an svn update of the file will do nothing.
- Unchanged, and out of date
The file has not been changed in the working directory, but it has been changed in the repository. The file should eventually be updated in order to make it current with the latest public revision. An svn commit of the file will do nothing, and an svn update of the file will fold the latest changes into your working copy.
- Locally changed, and out of date
The file has been changed both in the working directory and in the repository. An svn commit of the file will fail with an “out of date” error. The file should be updated first; an svn update command will attempt to merge the public changes with the local changes. If Subversion can’t complete the merge in a plausible way automatically, it leaves it to the user to resolve the conflict.
This may sound like a lot to keep track of, but the svn status command will show you the state of any item in your working copy. For more information on that command, refer to See an overview of your changes.