Re: [boost] [GitHelp] (Mis-)Understanding merge

Subject: Re: [boost] [GitHelp] (Mis-)Understanding merge
From: Daniel James (dnljms_at_[hidden])
Date: 2014-02-26 02:28:06

On 26 February 2014 06:50, Edward Diener <eldiener_at_[hidden]> wrote:
> I was following Modular Boost document "Establishing a merge point after SVN
> Conversion" (https://svn.boost.org/trac/boost/wiki/PostCvtMergePoint) and
> everything appeared to go well. I did my 'merge', 'commit', and 'push'
> specified at the end of the document and things seemed pretty good so I was
> confident I had established a correct merge point.
>
> Knowing that the latest 'develop' had been pushed and tested I determined to
> update 'master' with the latest 'develop' prior to pushing it. So I did a
> merge from 'develop' to 'master' and after carefully fixing a few minor
> conflicts in favor of the 'develop' versions the merge was successful.
>
> Yet when I looked at the files involved I noticed that a file which was in
> 'develop' was not in 'master'. How can this be ? If I merge from 'develop'
> to 'master' are not any files in 'develop' which are not in 'master' added
> automatically to 'master' ? If this is not the case it seems that a 'merge'
> is not doing what I expect it to do. Am I really expected to have to
> manually add files to 'master' which are in 'develop' and not in 'master'
> prior to the merge, or I have I missed some 'merge' functionality that would
> have done this for me automatically ?

Assuming you're talking about preprocessor there are a lot of
differences between master and your merge base, when you merge git
won't take these into account - it only deals with changes made after
the last merge. This is the tricky thing about transitioning from
subversion to git, they have different models of merging, subversion
is based on tracking individual changesets, git is based on the
history graph. You could try finding the old changesets that haven't
been merged and cherry pick them. In this case, I found the commit by
doing:

    > git log origin/develop --
include/boost/preprocessor/seq/variadic_seq_to_seq.hpp

    commit b60a47252d1b87d169bc4eac2b19f6c2916e9983
    Author: Paul Mensonides <pmenso57_at_[hidden]>
    Date:   Wed Sep 26 04:50:27 2012

       added VARIADIC_SEQ_TO_SEQ

       [SVN r80704]

This gave me the change that need to be cherry picked:

    > git cherry-pick b60a47252d1b87d169bc4eac2b19f6c2916e9983

But even after doing that there are still a lot of old changes that
need to be merged, mainly in the documentation:

    > git diff --stat 5e0422ff9732b0ddb2908f381d58d6241b0d8461
                (master)
    doc/headers.html                             | 32
++++++++++++++++----------------
    doc/headers/facilities.html                  |  2 +-
    doc/headers/facilities/overload.html         |  4 ++--
    doc/headers/tuple.html                       | 18 +++++++++---------
    doc/headers/tuple/eat.html                   |  2 +-
    doc/headers/tuple/elem.html                  |  2 +-
    doc/headers/tuple/enum.html                  |  4 ++--
    doc/headers/tuple/rem.html                   |  4 ++--
    doc/headers/tuple/reverse.html               |  2 +-
    doc/headers/tuple/size.html                  |  4 ++--
    doc/headers/tuple/to_array.html              |  4 ++--
    doc/headers/tuple/to_list.html               |  2 +-
    doc/headers/tuple/to_seq.html                |  2 +-
    doc/headers/variadic.html                    | 14 +++++++-------
    doc/headers/variadic/elem.html               |  4 ++--
    doc/headers/variadic/size.html               |  4 ++--
    doc/headers/variadic/to_array.html           |  4 ++--
    doc/headers/variadic/to_list.html            |  4 ++--
    doc/headers/variadic/to_seq.html             |  4 ++--
    doc/headers/variadic/to_tuple.html           |  4 ++--
    doc/ref.html                                 | 36
++++++++++++++++++------------------
    doc/ref/overload.html                        |  4 ++--
    doc/ref/tuple_eat.html                       |  8 ++++----
    doc/ref/tuple_elem.html                      |  6 +++---
    doc/ref/tuple_enum.html                      |  8 ++++----
    doc/ref/tuple_rem.html                       |  8 ++++----
    doc/ref/tuple_rem_ctor.html                  |  8 ++++----
    doc/ref/tuple_reverse.html                   |  8 ++++----
    doc/ref/tuple_size.html                      |  4 ++--
    doc/ref/tuple_to_array.html                  |  8 ++++----
    doc/ref/tuple_to_list.html                   |  8 ++++----
    doc/ref/tuple_to_seq.html                    |  8 ++++----
    doc/ref/variadic_elem.html                   |  4 ++--
    doc/ref/variadic_seq_to_seq.html             |  2 +-
    doc/ref/variadic_size.html                   |  4 ++--
    doc/ref/variadic_to_array.html               |  4 ++--
    doc/ref/variadic_to_list.html                |  4 ++--
    doc/ref/variadic_to_seq.html                 |  2 +-
    doc/ref/variadic_to_tuple.html               |  4 ++--
    doc/topics/variadic_macros.html              |  7 ++++---
    include/boost/preprocessor.hpp               |  2 +-
    include/boost/preprocessor/config/config.hpp |  2 +-
    42 files changed, 135 insertions(+), 134 deletions(-)

You could try to track down all the appropriate changes, but IMO the
best thing to do is to get develop to a release-worthy point and just
overwrite master from develop.