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Re: [PATCH] Add URL support for propset and propdel and fix URL support for propedit

From: David James <james_at_cs.toronto.edu>
Date: Fri, 22 Feb 2008 14:03:04 -0800

On Fri, Feb 22, 2008 at 11:44 AM, <kmradke_at_rockwellcollins.com> wrote:
> "Mark Phippard" <markphip_at_gmail.com> wrote on 02/22/2008 01:34:23 PM:
>
> > 2008/2/22 Kevin Radke <kmradke_at_gmail.com>:
> > > This is my first attempt at a patch to add URL support to the propset
> > > and propdel subcommands of svn. In doing so, I also noticed that
> > > propedit did not support multiple URL arguments correctly.
> > >
> > > I needed URL functionality for propdel, since we had a repository
> which
> > > had the svn:special property set for a file that was not special. I
> was
> > > unable to create a working copy with this file due to this error, and
> > > I was also unable to delete the property since you previously needed
> > > a working copy to delete properties. I was able to use this modified
> > > propdel to delete the incorrect property directly in the repository.
> >
> > What is the stuff about the -r parameter for? We would never allow
> > you to go back in time and delete or edit a property, only HEAD. Is
> > it being used for some other purpose?
> >
> > I am just going by the email, have not looked at the patch.
>
> Needed a way to specify a "base revision", because of the possible
> race condition between looking at the properties and then
> performing a command directly on the repository.
>
> We kicked around a --base-rev parameter in another thread, but
> it was easier for me to "overload" the meaning of -r here.
>
> Not using -r and using some other parameter is definitely a
> (probably less confusing) option.
>
> We could also assume "HEAD" (others didn't like this)
>
> Is peg revision syntax appropriate? (no idea on this)

I think that 'svn propdel' and 'svn propset' should assume the
"base-rev" is HEAD. Here's why:
  - If the file currently exists, svn rm already assumes that the
base-rev is HEAD. So svn propdel should do the same when the property
exists.
  - If the file does not exist, svn import already assumes that the
base-rev is HEAD. So svn propset should do the same when the property
does not exist.

Based on the above, there is only one situation where you need to
specify a base revision -- if you are trying to modify (but not
delete) a property which is already present in the repository. In
other cases, you can specify a base revision if you want to have
additional safety constraints, but there is no need to do so.

Some more comments:
  - If a pegrev is explicitly specified, the base rev should default
to the pegrev.
  - If you leave out the revision, or explicitly specify "-r HEAD" or
file_at_HEAD for 'svn propset', svn propset should check to see if the
property already exists in the repository. If the property already
exists, an error message should be printed which explains that a
base-rev is required.

I can also think of a few places outside of the 'svn prop*" commands
where base revs might be useful:
  - In future, I think we should extend the 'svn rm', and 'svn import'
commands to also support base revisions. In both cases, this would
allow for additional safety when you want to be sure you aren't
overwriting someone else's changes. In the case of 'svn import' if you
specify a base-rev, you can actually overwrite an existing file in the
repository with a new version.
  - In future, we might also want to extend 'svn cp' and 'svn mv' to
support base revs and a --replace option. This would allow, in theory,
for users to overwrite a file or directory which is already present in
the repository with a new version in a single commit.

Based on the fact that base revs might be useful in future in commands
which already accept the '-r' option, I think that we should use a
different option for 'base-rev', such as --base-rev.

Cheers,

David

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Received on 2008-02-22 23:03:22 CET

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