[LLVMdev] Moving CVS Files

[John Criswell]

Chris Morgan wrote:
> Any reason not to upgrade to subversion?  It does a much better job
> with handling moved or renamed files although svn doesn't actually
> store a 'move' or a 'rename' as a single versioned operation.

We discussed moving to another revision control system about a year ago, 
if I recall correctly.  At that time, we decided not to move to another 
system.  I don't recall the exact reasons for not switching, but part of 
it was that CVS is the "standard" revision control system out there 
(i.e. everyone already has it on their system).  I also recall that, at 
the time, the cost of switching outweighed the benefits we thought we'd 
gain.

Right now, the moving of files doesn't happen often enough to warrant a 
change in software (IMHO).  I just think that we as a group need to 
exercise more care when moving files so that we minimize the problems 
that arise.

-- John T.


> 
> Chris
> 
> 
> On 11/15/05, John Criswell <criswell at cs.uiuc.edu> wrote:
> 
>>Dear All,
>>
>>For those of you who have write access to the LLVM CVS repository, I
>>need to ask you to take more care when moving or renaming files.  If
>>done improperly, moving files can cause headaches when doing updates
>>from the repository or merging revisions between branches (which is
>>becoming more common with the vector_llvm branch).
>>
>>There are two ways that you can move a CVS file:
>>
>>1) Use the CVS commands:
>>
>>a) cd into your working directory.  Move the file from the old location
>>to the new location.
>>
>>b) Use cvs rm to remove the file from its old location.
>>
>>c) Use cvs add to add the file to its new location.
>>
>>d) Use cvs ci to commit the remove and addition of the file.  In the
>>logs, note the old and new locations of the file.
>>
>>This approach is simple and it allows files to be added and removed
>>properly when using cvs up to update a working directory or merge
>>revisions in different branches.  It also maintains all of the CVS tags
>>on the files correctly.
>>
>>The problem with this approach is that it does not copy over all of the
>>revision history from the old location to the new location.
>>
>>2) Manipulate the CVS Repository directly:
>>
>>This method will allow you to copy the revision history of a file into a
>>new location.  However, you have to perform this operation carefully;
>>failure to do it right will make merging to/from branches and cvs
>>updates difficult.
>>
>>Even if you follow these directions, I can't guarantee that cvs up is
>>going to work correctly in all cases.  But if you're going to copy the
>>revision history, following the directions below should help alleviate
>>some of the problems.
>>
>>a) cd into the CVS repository and *copy* the RCS file (the file ending
>>with a ,v) from the old location to the new location inside the repository.
>>
>>Please do NOT remove the old RCS file from the repository.
>>
>>Please do NOT move it using the mv command.
>>
>>b) cd into your working copy.  Use rm and cvs rm to remove the file from
>>its old location.  Then use cvs ci to commit the change.  Make a note in
>>the commit log that you've moved the file, and please indicate its new
>>location.
>>
>>c) Use cvs up in your working directory to get a copy of the file in its
>>new location.
>>
>>d) The file in its new location will have all of the CVS tags that it
>>had in its old location (the revision history also contains all of the
>>tag information).  Use cvs tag -d to remove all of the tags from the new
>>file.
>>
>>Doing this should ensure that the file does not show up in its new
>>location when checking out older versions of the source code, nor will
>>the file magically appear in a branch that it didn't exist in before.
>>
>>e) It may also be good to send email to llvmdev detailing what has been
>>moved.
>>
>>My recommendation is to use approach #1 as it is less error prone.
>>Approach #2 may still cause problems when merging to/from branches, but
>>it should be easier to track where a file has gone if the old version
>>has been cvs rm'ed.
>>
>>Improvements and corrections to the directions above are welcome.  Any
>>input on how to use Approach #2 and still get cvs up to move files
>>correctly when merging to/from branches would be great.
>>
>>Thanks everybody.
>>
>>-- John T.
>>
>>--
>>John T. Criswell
>>Research Programmer
>>University of Illinois at Urbana-Champaign
>>"It's today!" said Piglet. "My favorite day," said Pooh.
>>
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> 
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-- 
John T. Criswell
Research Programmer
University of Illinois at Urbana-Champaign
"It's today!" said Piglet. "My favorite day," said Pooh.