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(cvs.info)Choosing a model

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Choosing between reserved or unreserved checkouts
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   Reserved and unreserved checkouts each have pros and cons.  Let it
be said that a lot of this is a matter of opinion or what works given
different groups' working styles, but here is a brief description of
some of the issues.  There are many ways to organize a team of
developers.  CVS does not try to enforce a certain organization.  It is
a tool that can be used in several ways.

   Reserved checkouts can be very counter-productive.  If two persons
want to edit different parts of a file, there may be no reason to
prevent either of them from doing so.  Also, it is common for someone
to take out a lock on a file, because they are planning to edit it, but
then forget to release the lock.

   People, especially people who are familiar with reserved checkouts,
often wonder how often conflicts occur if unreserved checkouts are
used, and how difficult they are to resolve.  The experience with many
groups is that they occur rarely and usually are relatively
straightforward to resolve.

   The rarity of serious conflicts may be surprising, until one realizes
that they occur only when two developers disagree on the proper design
for a given section of code; such a disagreement suggests that the team
has not been communicating properly in the first place.  In order to
collaborate under _any_ source management regimen, developers must
agree on the general design of the system; given this agreement,
overlapping changes are usually straightforward to merge.

   In some cases unreserved checkouts are clearly inappropriate.  If no
merge tool exists for the kind of file you are managing (for example
word processor files or files edited by Computer Aided Design
programs), and it is not desirable to change to a program which uses a
mergeable data format, then resolving conflicts is going to be
unpleasant enough that you generally will be better off to simply avoid
the conflicts instead, by using reserved checkouts.

   The watches features described above in Note: Watches can be
considered to be an intermediate model between reserved checkouts and
unreserved checkouts.  When you go to edit a file, it is possible to
find out who else is editing it.  And rather than having the system
simply forbid both people editing the file, it can tell you what the
situation is and let you figure out whether it is a problem in that
particular case or not.  Therefore, for some groups it can be
considered the best of both the reserved checkout and unreserved
checkout worlds.