Re: What is HEAD?

[Ming Kin Lai]

> > Larry Jones writes:
> > That description is lacking.  The manual source contains the following...:
> >
> > @c FIXME: What does HEAD really mean?  I believe that
> > @c the current answer is the head of the default branch
> > @c for all cvs commands except diff.  For diff, it
> > @c seems to be (a) the head of the trunk (or the default
> > @c branch?) if there is no sticky tag, (b) the head of the
> > @c branch for the sticky tag, if there is a sticky tag.
> > @c (b) is ugly as it differs
> > @c from what HEAD means for other commands, but people
> > @c and/or scripts are quite possibly used to it.
> >
> > The "head" of a branch (or trunk) is also called the "tip" and refers to
> > the highest numbered revision on the branch.  The "default branch" is
> > generally the vendor branch if the file has been imported and not
> > locally modified, and the trunk otherwise.
>
> I need some clarification and confirmaton.  By "default branch", you do not 
> mean a branch created by
> cvs tag -b mybranch
> You mean either the "vendor branch" that is imported or the trunk.  Right?
> Therefore even if I am on mybranch, with diff and no sticky tag and the 
> file is not imported, or a command other than diff, HEAD does not mean the 
> tip of mybranch, but still means the tip of the trunk. With diff and a 
> sticky tag, HEAD is the tip of mybranch.  Right?

Seems right!  I did a little experiment: Revision 1.3 is my branch point, 
which I tagged Root-of-mybranch.  I added the word "thrice" to the fle and 
committed it as Revision 1.4.  Then I did a update -r mybranch to go on the 
branch.  I added the word "fourtimes" there and committed it as Revision 
1.3.2.1.

address@hidden cvs status -v
cvs status: Examining proj
===============================================
File: test3             Status: Up-to-date

  Working revision:    1.3.2.1 Sun Sep 11 00:56:21 2005
  Repository revision: 1.3.2.1 /home/mingl/shitrepo/proj/test3,v
  Sticky Tag:          mybranch (branch: 1.3.2)
  Sticky Date:         (none)
  Sticky Options:      (none)

  Existing Tags:
       mybranch                        (branch: 1.3.2)
       Root-of-branch                  (revision: 1.3)
       release                         (revision: 1.1.1.1)
       vendor                          (branch: 1.1.1)

address@hidden cvs diff -r 1.3.2.1 -r HEAD test3

address@hidden cvs diff -r 1.3.2.1 -r 1.4 test3
Index: test3
===============================================
RCS file: /home/mingl/shitrepo/proj/test3,v
retrieving revision 1.3.2.1
retrieving revision 1.4
diff -r1.3.2.1 -r1.4
4c4
< fourtimes
---
> thrice

address@hidden cvs diff -r HEAD -r 1.4 test3
Index: test3
===============================================
RCS file: /home/mingl/shitrepo/proj/test3,v
retrieving revision 1.3.2.1
retrieving revision 1.4
diff -r1.3.2.1 -r1.4
4c4
< fourtimes
---
> thrice

Obviously HEAD is 1.3.2.1, tip of mybranch.

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