Re: [RFC] mtn to git conversion script

> On Sun, Aug 24, 2008 at 12:18:50PM +0300, Felipe Contreras wrote:
>> I developed a script that converts a monotone repository into a git
>> one (exact clone), I want to contribute it so everybody can use it.
>>
>> This is the gist of the script:
>>
>> mtn update --revision #{@id} --reallyquiet
>> git ls-files --modified --others --exclude-standard -z | git
>> update-index --add --remove -z --stdin
>> git write-tree
>> git write-raw < /tmp/commit.txt
>> git update-ref refs/mtn/#{@id} #{@git_id}
>>
>> branches.each do |e|
>>     git update-ref refs/heads/#{e} #{@git_id}
>> end
>
> You definitely want to use fast-import, but you probably want to do
> something a lot closer to fast-export for monotone (read: use its
> automate stdio interface and avoid expensive calls).
>
> Here's a simple monotone to git converter I wrote.  You'll need the
> Monotone::AutomateStdio perl module to use it (which I think I got it
> from monotone's net.venge.monotone.contrib.lib.automate-stdio branch).
> It is very fast; it can convert the OpenEmbedded repo in something like
> 5-10 minutes on my machine.

> Note that for monotone export to go fast you absolutely /must/ avoid the
> get_manifest operation.  In my converter I use the revision information
> directly.  Getting the renames right with this is a little tricky; IIRC,
> the ordering that works is:
>
> * Rename all renamed files, innermost files first, to temporary names.
> * Delete all deleted files, innermost first.
> * Rename all temporary names to permanent names, outermost first.
> * Add all new/modified files.
>
> Conveniently, all of the above can be done by directly emitting
> fast-import commands, so you don't have to keep track of trees directly.
> (With one exception, which I'll elaborate on in a different email.)