Re: New branch name with no other changes

On Fri, Jun 10, 2011 at 07:03:55AM -0700, Stephen Leake wrote:
> Quoting Hendrik Boom <[email protected]>:
>
>> On Thu, Jun 09, 2011 at 02:14:16PM -0400, Hendrik Boom wrote,
>>
>> but forgot to mention he was using mtn 1.0:
>>
>>> I checked out a new workspace, and I want to check it in again unchenged
>>> with a new branch name  -- the one I want to use to make changes.  I'd
>>> like to make it clear that the new branch is starting in the same state
>>> as the current head in the old one.
>
> I use this:
>
> function gds_create_mission(mission, from_branch, new_branch)
>    local from_project, new_project, result, output, rev
>
>    from_project = mission .. "." .. from_branch
>    new_project = mission .. "." .. new_branch
>
>    io.write("checking ...\n")
>    result, output = mtn_automate("branches")
>    if not result then
>       error(string.format("Error from 'mtn_automate branches %s'", output))
>    end
>
>    if string.find (output, new_project) then
>       error(string.format("%s branch already declared", new_project))
>    end
>
>    result, output = mtn_automate("heads", from_project)
>    if not result then
>       error(string.format("Error from 'mtn_automate heads %s'", from_project))
>    end
>
>    -- A single head gives an output with a single 40 byte rev id, plus 
> newline.
>    if #output > 41 then
>       error(string.format("%s has multiple heads; need merge", from_project))
>    end
>
>    io.write(string.format("creating %s from %s\n", new_project, from_project))
>    result, output = mtn_automate("select", "h:" .. from_project)
>    if not result then
>       error(string.format("Error from 'mtn_automate select %s'", "h:" .. 
> from_project))
>    end
>    rev = string.sub(output, 1, 40)
>    result, output = mtn_automate("cert", rev, "branch", new_project)
>    if not result then
>       error(string.format("Error from 'mtn_automate cert %s branch %s : 
> %s'", rev, new_project, output))
>    end
> end
>
> register_command("gds_create_mission", "mission from_branch new_branch", 
> "create mtn branch for a GDS mission",
>       "Create mtn branch derived from FROM_BRANCH, in MISSION.",
>       "gds_create_mission")
>
> The key command is "automate cert"; just add the new branch cert to the 
> existing revision.
>
> There have been discussions before about making something like this part 
> of mtn, but nothing has been agreed on.

Actually, the approve command worked fine, though it took a few moments 
to determine the right revision ID.  Maybe approving the revision in the 
current workspace should be an option on that command?  I wouldn't want 
it to be the default: too easy to approve the wrong thing by accident.

But to me, the obvious thing was to commit with an explicit branch 
option.  Which didn't work.

--- hendrik