Re: [CEDET-devel] transplant revisions between unrelated projects

[Lluís <xscript@gmx.net>]

Stefan Monnier writes:

>>>> You can find the code here:
>>>> https://launchpad.net/bzr-tp/trunk
>>>> This will give some more details on how to use it:
>>>> bzr help transplant
>>> Could you describe (or point to a description) of what it actually does?
>> Could be seen like an inter-project merge tool, where history is kept
>> (including merges), as long as the "transplanted" revisions affect
>> files identified as "transplantable".

>> For example, emacs->cedet synchronization would transplant files
>> "lisp/emacs-lisp/eieio\(.*\).el" from emacs into
>> "lisp/eieio/eieio\1.el" in cedet, where cedet controls what to
>> transplant and when (transplant metadata is committed into the cedet
>> branch):

> I understand that, but I don't understand how it does it.  It seems like
> it works a bit like a "rebase".  So, what does "history is kept"
> mean exactly?  Will a "bzr tp-from" (once "tp-from-finish"ed) appear
> as a merge in the DAG?

AFAIU it's a mix between rebasing and merging, as the shape of the DAG in the
transplanted revisions from "emacs" should be kept in "cedet".

Example of log showing all levels (-n 0) in "emacs" (c* are the commit
messages):

* c1
* c2
* [merge] c3
  * c4
  * c5
  * c6
* c7

Assuming "c1" was already transplanted into cedet sometime in the past, this is
what you should get after the transplant from "emacs" into "cedet":

* [merge] Transplant from 'emacs': <revid of c2>..<revid of c7>
  * c2
    Transplant from 'emacs': <revid of c2>
  * [merge] c3
    Transplant from 'emacs': <revid of c3>
    * c4
      Transplant from 'emacs': <revid of c4>
    * c5
      Transplant from 'emacs': <revid of c5>
    * c6
      Transplant from 'emacs': <revid of c6>
  * c7
    Transplant from 'emacs': <revid of c7>


Sorry if I haven't used the appropriate bazaar concepts.

You can see the main algorithm here:
  http://bazaar.launchpad.net/~lluis.vilanova/bzr-tp/trunk/view/head:/transplant.py#L250


Lluis

-- 
 "And it's much the same thing with knowledge, for whenever you learn
 something new, the whole world becomes that much richer."
 -- The Princess of Pure Reason, as told by Norton Juster in The Phantom
 Tollbooth