59ab4eb36e
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
76 lines
2.9 KiB
Plaintext
76 lines
2.9 KiB
Plaintext
Date: Sat, 5 Jan 2008 20:17:40 -0500
|
|
From: Sean <seanlkml@sympatico.ca>
|
|
To: Miklos Vajna <vmiklos@frugalware.org>
|
|
Cc: git@vger.kernel.org
|
|
Subject: how to use git merge -s subtree?
|
|
Abstract: In this article, Sean demonstrates how one can use the subtree merge
|
|
strategy.
|
|
Content-type: text/asciidoc
|
|
Message-ID: <BAYC1-PASMTP12374B54BA370A1E1C6E78AE4E0@CEZ.ICE>
|
|
|
|
How to use the subtree merge strategy
|
|
=====================================
|
|
|
|
There are situations where you want to include contents in your project
|
|
from an independently developed project. You can just pull from the
|
|
other project as long as there are no conflicting paths.
|
|
|
|
The problematic case is when there are conflicting files. Potential
|
|
candidates are Makefiles and other standard filenames. You could merge
|
|
these files but probably you do not want to. A better solution for this
|
|
problem can be to merge the project as its own subdirectory. This is not
|
|
supported by the 'recursive' merge strategy, so just pulling won't work.
|
|
|
|
What you want is the 'subtree' merge strategy, which helps you in such a
|
|
situation.
|
|
|
|
In this example, let's say you have the repository at `/path/to/B` (but
|
|
it can be an URL as well, if you want). You want to merge the 'master'
|
|
branch of that repository to the `dir-B` subdirectory in your current
|
|
branch.
|
|
|
|
Here is the command sequence you need:
|
|
|
|
----------------
|
|
$ git remote add -f Bproject /path/to/B <1>
|
|
$ git merge -s ours --no-commit Bproject/master <2>
|
|
$ git read-tree --prefix=dir-B/ -u Bproject/master <3>
|
|
$ git commit -m "Merge B project as our subdirectory" <4>
|
|
|
|
$ git pull -s subtree Bproject master <5>
|
|
----------------
|
|
<1> name the other project "Bproject", and fetch.
|
|
<2> prepare for the later step to record the result as a merge.
|
|
<3> read "master" branch of Bproject to the subdirectory "dir-B".
|
|
<4> record the merge result.
|
|
<5> maintain the result with subsequent merges using "subtree"
|
|
|
|
The first four commands are used for the initial merge, while the last
|
|
one is to merge updates from 'B project'.
|
|
|
|
Comparing 'subtree' merge with submodules
|
|
-----------------------------------------
|
|
|
|
- The benefit of using subtree merge is that it requires less
|
|
administrative burden from the users of your repository. It works with
|
|
older (before Git v1.5.2) clients and you have the code right after
|
|
clone.
|
|
|
|
- However if you use submodules then you can choose not to transfer the
|
|
submodule objects. This may be a problem with the subtree merge.
|
|
|
|
- Also, in case you make changes to the other project, it is easier to
|
|
submit changes if you just use submodules.
|
|
|
|
Additional tips
|
|
---------------
|
|
|
|
- If you made changes to the other project in your repository, they may
|
|
want to merge from your project. This is possible using subtree -- it
|
|
can shift up the paths in your tree and then they can merge only the
|
|
relevant parts of your tree.
|
|
|
|
- Please note that if the other project merges from you, then it will
|
|
connect its history to yours, which can be something they don't want
|
|
to.
|