Re: A second cvs checkout (or export) clears file locks :-(

[Todd Denniston]

Peter Toft wrote, On 05/08/2008 04:16 AM:
> On Wed, 07 May 2008 10:27:03 +0200, Peter Toft <pto@linuxbog.dk> wrote:
> > On Wed, 07 May 2008 09:21:56 +0200, Peter Toft <pto@linuxbog.dk> wrote:
> > > Hi all
> > >
> > > I like to draw your attention towards a nasty limitation to CVS locks,
> > > which 
> > > I at least did not know until now.
> > I forgot to mention that I have prior to the stuff below set
> > cvs watch on README.txt
> >
> > Best
> >
> > /peter
>
>
> IMHO it is a design-flaw since I could easily be in a situation, 

I think what we are seeing here is a failing in the documentation, most likely 
because so few folks attempt to do anything resembling locking anymore (most 
times you just don't need it).
After you understand how to get the commands to do what you want, could you 
please make a set of suggested changes to the cederqvist manual[1] and submit 
that back to bug-cvs, so that the edit and watchers commands might be better 
understood by later folks who want to use them.

[1] http://ximbiot.com/cvs/manual/
> where I
> like to signal that I am working on a certain file, i.e. I use 
> cvs watch on + cvs edit
> but somebody asks me to export the module or test something where I need to
> check out the same module in parallel to the first checkout.
>
> I find this behaviour with CVS 1.12.13.
>
> Is there any way to avoid this clearing of file locks?

The first thing you will need to wrap your head around is
CVS DOES NOT LOCK FILES, it puts advisory marks on them called watches.

reading  `cvs --help-commands 2>&1|grep edit`

makes it clear that the commands you want to work with only work on watched 
files.
IIRC if someone puts a watch on a file they will get an notification if 
someone else does one of the actions they are watching it for, i.e., _EACH_ of 
the folks that might want to edit the files you are protecting (README.txt) 
need to do
`cvs watch add -a all README.txt`
at that point you should be able to do
`cat $CVSROOT/my_prog/CVS/fileattr` and see all those folks watching the file.

The following script I think shows how to make it work (note, I have only 
rarely used watchers and have never used edit&unedit):
cd /tmp/
 mkdir testcvs
 mkdir testcvs/testrepo
export CVSROOT=/tmp/testcvs/testrepo/
 cd testcvs/
 cvs init
 mkdir testrepo/baseline
 cvs checkout baseline
 cd baseline/
 touch testfile.txt
 date > testfile2.txt
cvs add testfile*
 cvs commit -m "need file"
cat $CVSROOT/baseline/CVS/fileattr


cvs edit testfile2.txt
cvs editors
#returns that I am editing testfile2.txt
cat $CVSROOT/baseline/CVS/fileattr
cd /tmp/testcvs
 mv baseline/ baseline.old
 cvs checkout baseline
cd baseline
cvs editors
#does not return that I am editing any files...

cd /tmp/testcvs/baseline.old
cvs edit -a edit testfile2.txt
cat $CVSROOT/baseline/CVS/fileattr
cd /tmp/testcvs/baseline
cvs editors
#returns that I am editing testfile2.txt


> Best
>
> Peter
>
>
> > >  $ cvs checkout my_proj
> > >  ... lots of check out lines...
> > >  $ cd my_proj
> > >  $ cvs editors             # No files will be shown since no files are
> > > locked
> > >  $ cvs edit README.txt
> > >  $ cvs editors .
> > >  README.txt    pto        Wed May  7 06:43:15 2008 -0000 myworkstation  
> >
> > >  /opt/cvsroot/my_proj
> > >  $ cd ..
> > >  $ mv my_proj my_proj_work
> > >  $ cvs checkout -r HEAD my_proj
> > >  $ ls -1d
> > >  my_proj              
> > >  my_proj_work
> > >  $ cd my_proj_work
> > >  $ cvs editors .
> > >
> > > Bummer - the lock on my_proj/README.txt is gone.... :-((
> > > Pure magic - but very annoying magic....
> > >
> > > How come? Can I make some different operation, where I don't loose the
> > > file
> > > lock.
> > >
> > > Note; If I replace the second "cvs checkout" with "cvs export" I have
> > the
> > > same problem.
> > >
> > >
> > > Best
> > >
> > > Peter Toft, Ph.D. [pto@linuxbog.dk] http://petertoft.dk   
> > >
> > >
> > >
> > > _______________________________________________
> > > Bug-cvs mailing list
> > > Bug-cvs@nongnu.org
> > > http://lists.nongnu.org/mailman/listinfo/bug-cvs


--
Todd Denniston
Crane Division, Naval Surface Warfare Center (NSWC Crane)
Harnessing the Power of Technology for the Warfighter