Using version control - IntelliJ IDEA in Action - page 279

Files marked as externally deleted are files that are missing from your working
directory but that IDEA wasn't responsible for deleting. This happens when you
delete the files from outside IDEA through the command line, the file explorer, or
another application. The option Show externally deleted lets you toggle the dis-
play of these items off and on.
Finally, the Show Changes command lets you view the line-by-line changes
you're committing. This is discussed in the next section.

8.2.4 Working with branches and tags

CVS derives its name (Concurrent Versioning System) from the fact that it lets you
maintain multiple simultaneous versions of your project through the uses of
branches and tags. A tag is a symbolic name assigned to the current version of all
the files in your project at a given point in time, generally a release or major mile-
stone. From then on, you can always retrieve a copy of your project the way it was
at that instant in time. A branch is a special type of tag that lets you fork off a sepa-
rate line of changes to your code, which varies independently of the trunk. Typi-
cally, this feature is used to build minor updates to the shipping release of the
project without having to include all the changes already made on the trunk.
Full instructions on using branches and tags are beyond the scope of this book,
but we'll explain how IDEA lets you use them.

Creating a tag
Creating a tag is relatively straightforward: Use the CVS | Create Tag command
to bring up the tag creation dialog. IDEA prompts for a valid CVS tag name. If you
want to replace an existing tag (or review your old tags), click the Browse button
to see the list of tags already present in the repository. An option is provided that
lets you replace all existing instances of the tag, if any are present. The other
option, Switch to this tag , updates your working directory to the specified tag.

Deleting a tag
Deleting a tag is equally straightforward: Select CVS | Delete Tag , choosing the
tag you wish to delete from the provided list. When you delete a tag, all you're
doing is removing the symbolic reference that links all the file versions under one
tag name. Files aren't deleted or modified in any way when you remove a tag.

Creating a branch
Creating a branch operates almost the same as creating a tag, primarily because
under CVS a branch is a special type of tag. Use CVS | Create Branch to bring up
the branch creation dialog, which looks exactly like the tag creation dialog. As