RE: merge mode for XML

[Noel Yap]

--- Paul Sander <address@hidden> wrote:
> >--- Forwarded mail from address@hidden
> 
> >Greg is talking about the second issue.  I have an
> >inkling keeping this info on a per-version basis
> won't
> >work but I haven't come up with anything
> substantial.
> 
> Here's one:
> 
> - Create a new file and check in a few versions on
> the trunk.
> - Create a branch.
> - Check in a few versions on the branch, but change
> the data type before
>   the first commit.  All versions on the branch
> contain the same data type,
>   but they differ from the trunk.
> - Merge the branch to the trunk *OR* update the
> branch from the trunk.
> 
> What's the correct action for the last step?  Is it
> to refuse to merge
> because the tools are different?  Is it to copy the
> contributor and change
> the data type on the target?  Is it to somehow
> convert one data type to
> the other and invoke the proper merge tool and
> record that tool with the
> next commit?
> 
> None of these choices is a good one because there
> are valid cases where
> each one is correct.  I'm inclined to go with the
> first one and diagnose
> an error, but I'm sure others would disagree.

Yes, I think it should be an error since it would be
unwise to expect CVS to be able to act on files of two
different types.  I guess ideally CVS would be able to
be configured to use diff/merge programs that did
their work on files of different types (eg similar to
overloaded functions), but this is way too much to
hope for.

As a workaround, the user can change the diff/merge
program for the trunk, then perform the operation
without impunity.

Come to think of it, you might've mentioned this
before, all that the file has to keep track of is its
type.  CVS can then map that type to a particular
diff/merge program.  This has two advantages:
1. Changing the diff/merge for a bunch of files with
the same type is easy.
2. Adding more type-specific behaviour in the future
would be easier.

Noel


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