Using shelve to mimic Git's staging area

[A. S. Budden]

On 27 September 2011 10:10, John Arbash Meinel <john at arbash-meinel.com> wrote:
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> On 9/27/2011 11:00 AM, A. S. Budden wrote:
>> Dear all,
>>
>> I've recently been experimenting with bzr shelve.  As I understand
>> it, this is intended to be an equivalent to the staging area in
>> git: I can make changes on two separate issues and then commit them
>> separately by moving one set of changes temporarily onto the shelf.
>> I hope I have understood that right.
>>
>> However, I have been unable to work out how to do this when
>> changes are close together in a file.  For example, imagine I had a
>> file stuff.c, which "bzr diff" reports as looking like this:
>>
>> === modified file 'Stuff.c' --- Stuff.c             2011-09-22
>> 14:04:20 +0000 +++ Stuff.c             2011-09-27 07:40:16 +0000 @@
>> -42,6 +42,8 @@ * Some random comments preceding the change * that
>> have already been committed. */ +/* I'd like to shelve this change
>> */ +/* But not this one */ void AFunctionThatHasNotChanged(void) {
>> uint8_t variable;
>>
>> With git, I can add one of those too new comment lines to the
>> staging area and commit, then add the other one and commit [1].
>> Obviously this is a rather contrived example, but is there any way
>> to do the equivalent of this with bzr (q)shelve?
>>
>> Thanks,
>>
>> Al
>>
>> [1] In the command line version of git, this is done by editing
>> the patch directly; in "git gui", you can right-click on a line and
>> select either "add hunk to staging area" or "add line to staging
>> area".
>>
>
> If you do "bzr config change_editor=???", and set that to a text
> editor, it will allow you to do "e" to edit the file.
> My change editor is configured to "vim -d".
>
> That gives you a side-by-side of the old value of the file, and the
> new value of the file. You edit the 'new' side until it looks like
> what you want to keep, and then save and exit. And then bzr will leave
> the new value to what you left it, and determine what diff gets
> shelved based on that.
>
> So in the above case you would hit 'e' then delete the "I want to
> shelve this line" case.

Sounds great, thank you.  However, I think I must be doing something
wrong.  What I did was to run "bzr shelve".  I then hit 'e' and gvim
(diff-mode) opened, so I deleted the line "I'd like to shelve this
change" and hit :wqa.  I hit 'y' and the change was shelved and I was
left with a working file with just the line "But not this one".  I
committed it and everything looked fine.  I then did "bzr unshelve"
and was told:

    Using changes with id "1".
     M  Stuff.c
    Text conflict in Stuff.c
    1 conflicts encountered.
    Deleted changes with id "1".

"bzr st" reported:

    modified:
      Stuff.c
    unknown:
      Stuff.c.BASE
      Stuff.c.OTHER
      Stuff.c.THIS
    conflicts:
      Text conflict in Stuff.c

and bzr diff (ignoring the lines of context) had this to say:

    -/* But not this one */
    +<<<<<<< TREE
    +/* But not this one */
    +=======
    +<<<<<<<
    +=======
    +/* I'd like to shelve this change */
    +/* But not this one */
    +>>>>>>>
    +>>>>>>> MERGE-SOURCE

I realise that this can be easily resolved with qconflicts or
whatever, but this does seem to make the process of committing the two
lines separately (which is what I want to achieve) a lot more
difficult.

Am I missing something obvious?

Al