Re: Two head revisions?

[Jim Hyslop]

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Derek R. Price wrote:
> Has anyone ever seen RCS archive corruption in the form of two head
> revisions or have any idea how it may have come about?

OK, here are some random thoughts, which may or may not be useful :=)

Could there be some hidden characters (e.g. embedded backspaces)?

The usual troubleshooting questions - does the problem manifest itself
only the one file, or on multiple files? If multiple files, is there any
common attribute of those files? What version of the client & server?
access method? mounting points (i.e. Samba, NFS, local, etc.)? I'm sure
you've gone over all that, of course, but if you can mention anything
out of the ordinary it might trigger some thoughts.

> 
> It appears to have happened as part of a commit.  The head revision was
> initially 1.4.  CVS overwrote the metadata entry for 1.4 (commit time,
> author, state, branches, next), but put a second, undiffed entry for the
> head revision after the first.  So, before the commit, the file probably
> looked like:

Hmmm... do you have access to any backups, which might show what the
file really did look like after Jane's commit and before Joe's commit?

...
> 
> Then, after the (otherwise successful) commit:
> 
> RCSHEADER
> 
> 1.4
> date YYYY.MM.DD.hh.mm.ss;     author joeschmoe;       state Exp;
> branches;
> next  1.3;

So, just to make sure I understand the problem correctly: here, we would
expect to see something like:

1.5
date YYYY.MM.DD.hh.mm.ss;       author joeshcmoe;       state Exp;
branches;
next    1.4;

followed by the revision data for Jane, for rev 1.4, right?

> 
> [REVISION METADATA 1.3-1.1)
> 
> desc
> @@
> 
> 1.4
> log
> @what jane did
> @
> text
> @jane's content
> @
> 
> 1.4
> log
> @what joe did
> @
> text
> @joe's content (based on jane's content, but not the diff from it)
> @

Interesting.

Here's a hypothesis: maybe before Joe's commit the revision metadata for
rev 1.4 was missing or corrupted, so CVS thought the most recent version
was 1.3, and ignored the existing 1.4 revision entry.

- --
Jim Hyslop
Dreampossible: Better software. Simply.     http://www.dreampossible.ca
                 Consulting * Mentoring * Training in
    C/C++ * OOD * SW Development & Practices * Version Management
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