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(cvsbook.info)Branches And Keyword Expansion -- Natural Enemies

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Branches And Keyword Expansion - Natural Enemies
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If your files contain RCS keywords that expand differently on branch and
trunk, you're almost guaranteed to get spurious conflicts on every
merge.  Even if nothing else changed, the keywords are overlapping, and
their expansions won't match.  For example, if README.txt contains this
on the trunk

     $Revision: 1.14 $

and this on the branch

     $Revision: 1.14.2.1 $

then when the merge is performed, you'll get the following conflict:

     floss$ cvs update -j Exotic_Greetings-branch
     RCS file: /usr/local/newrepos/myproj/README.txt,v
     retrieving revision 1.14
     retrieving revision 1.14.2.1
     Merging differences between 1.14 and 1.14.2.1 into README.txt
     rcsmerge: warning: conflicts during merge
     floss$ cat README.txt
      ...
     <<<<<<< README.txt
     key $Revision: 1.14 $
     =======
     key $Revision: 1.14.2.1 $
     >>>>>>> 1.14.2.1
      ...
     floss$

To avoid this, you can temporarily disable expansion by passing the -kk
option (I don't know what it stands for; "kill keywords" maybe?) when
you do the merge:

     floss$ cvs update -kk -j Exotic_Greetings-branch
     RCS file: /usr/local/newrepos/myproj/README.txt,v
     retrieving revision 1.14
     retrieving revision 1.14.2.1
     Merging differences between 1.14 and 1.14.2.1 into README.txt
     floss$ cat README.txt
      ...
     $Revision$
      ...
     floss$

There is one thing to be careful of, however: If you use -kk, it
overrides whatever other keyword expansion mode you may have set for
that file.  Specifically, this is a problem for binary files, which are
normally -kb (which suppresses all keyword expansion and line-end
conversion).  So if you have to merge binary files in from a branch,
don't use -kk.  Just deal with the conflicts by hand instead.