You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
171 lines
5.9 KiB
171 lines
5.9 KiB
git-merge(1) |
|
============ |
|
|
|
NAME |
|
---- |
|
git-merge - Join two or more development histories together |
|
|
|
|
|
SYNOPSIS |
|
-------- |
|
[verse] |
|
'git-merge' [-n] [--stat] [--no-commit] [--squash] [-s <strategy>]... |
|
[-m <msg>] <remote> <remote>... |
|
'git-merge' <msg> HEAD <remote>... |
|
|
|
DESCRIPTION |
|
----------- |
|
This is the top-level interface to the merge machinery |
|
which drives multiple merge strategy scripts. |
|
|
|
The second syntax (<msg> `HEAD` <remote>) is supported for |
|
historical reasons. Do not use it from the command line or in |
|
new scripts. It is the same as `git merge -m <msg> <remote>`. |
|
|
|
|
|
OPTIONS |
|
------- |
|
include::merge-options.txt[] |
|
|
|
-m <msg>:: |
|
The commit message to be used for the merge commit (in case |
|
it is created). The `git-fmt-merge-msg` script can be used |
|
to give a good default for automated `git-merge` invocations. |
|
|
|
<remote>:: |
|
Other branch head merged into our branch. You need at |
|
least one <remote>. Specifying more than one <remote> |
|
obviously means you are trying an Octopus. |
|
|
|
include::merge-strategies.txt[] |
|
|
|
|
|
If you tried a merge which resulted in a complex conflicts and |
|
would want to start over, you can recover with |
|
linkgit:git-reset[1]. |
|
|
|
CONFIGURATION |
|
------------- |
|
include::merge-config.txt[] |
|
|
|
branch.<name>.mergeoptions:: |
|
Sets default options for merging into branch <name>. The syntax and |
|
supported options are equal to that of git-merge, but option values |
|
containing whitespace characters are currently not supported. |
|
|
|
HOW MERGE WORKS |
|
--------------- |
|
|
|
A merge is always between the current `HEAD` and one or more |
|
commits (usually, branch head or tag), and the index file must |
|
exactly match the |
|
tree of `HEAD` commit (i.e. the contents of the last commit) when |
|
it happens. In other words, `git-diff --cached HEAD` must |
|
report no changes. |
|
|
|
[NOTE] |
|
This is a bit of a lie. In certain special cases, your index is |
|
allowed to be different from the tree of the `HEAD` commit. The most |
|
notable case is when your `HEAD` commit is already ahead of what |
|
is being merged, in which case your index can have arbitrary |
|
differences from your `HEAD` commit. Also, your index entries |
|
may have differences from your `HEAD` commit that match |
|
the result of a trivial merge (e.g. you received the same patch |
|
from an external source to produce the same result as what you are |
|
merging). For example, if a path did not exist in the common |
|
ancestor and your head commit but exists in the tree you are |
|
merging into your repository, and if you already happen to have |
|
that path exactly in your index, the merge does not have to |
|
fail. |
|
|
|
Otherwise, merge will refuse to do any harm to your repository |
|
(that is, it may fetch the objects from remote, and it may even |
|
update the local branch used to keep track of the remote branch |
|
with `git pull remote rbranch:lbranch`, but your working tree, |
|
`.git/HEAD` pointer and index file are left intact). |
|
|
|
You may have local modifications in the working tree files. In |
|
other words, `git-diff` is allowed to report changes. |
|
However, the merge uses your working tree as the working area, |
|
and in order to prevent the merge operation from losing such |
|
changes, it makes sure that they do not interfere with the |
|
merge. Those complex tables in read-tree documentation define |
|
what it means for a path to "interfere with the merge". And if |
|
your local modifications interfere with the merge, again, it |
|
stops before touching anything. |
|
|
|
So in the above two "failed merge" case, you do not have to |
|
worry about loss of data --- you simply were not ready to do |
|
a merge, so no merge happened at all. You may want to finish |
|
whatever you were in the middle of doing, and retry the same |
|
pull after you are done and ready. |
|
|
|
When things cleanly merge, these things happen: |
|
|
|
1. The results are updated both in the index file and in your |
|
working tree; |
|
2. Index file is written out as a tree; |
|
3. The tree gets committed; and |
|
4. The `HEAD` pointer gets advanced. |
|
|
|
Because of 2., we require that the original state of the index |
|
file to match exactly the current `HEAD` commit; otherwise we |
|
will write out your local changes already registered in your |
|
index file along with the merge result, which is not good. |
|
Because 1. involves only the paths different between your |
|
branch and the remote branch you are pulling from during the |
|
merge (which is typically a fraction of the whole tree), you can |
|
have local modifications in your working tree as long as they do |
|
not overlap with what the merge updates. |
|
|
|
When there are conflicts, these things happen: |
|
|
|
1. `HEAD` stays the same. |
|
|
|
2. Cleanly merged paths are updated both in the index file and |
|
in your working tree. |
|
|
|
3. For conflicting paths, the index file records up to three |
|
versions; stage1 stores the version from the common ancestor, |
|
stage2 from `HEAD`, and stage3 from the remote branch (you |
|
can inspect the stages with `git-ls-files -u`). The working |
|
tree files have the result of "merge" program; i.e. 3-way |
|
merge result with familiar conflict markers `<<< === >>>`. |
|
|
|
4. No other changes are done. In particular, the local |
|
modifications you had before you started merge will stay the |
|
same and the index entries for them stay as they were, |
|
i.e. matching `HEAD`. |
|
|
|
After seeing a conflict, you can do two things: |
|
|
|
* Decide not to merge. The only clean-up you need are to reset |
|
the index file to the `HEAD` commit to reverse 2. and to clean |
|
up working tree changes made by 2. and 3.; `git-reset` can |
|
be used for this. |
|
|
|
* Resolve the conflicts. `git-diff` would report only the |
|
conflicting paths because of the above 2. and 3.. Edit the |
|
working tree files into a desirable shape, `git-add` or `git-rm` |
|
them, to make the index file contain what the merge result |
|
should be, and run `git-commit` to commit the result. |
|
|
|
|
|
SEE ALSO |
|
-------- |
|
linkgit:git-fmt-merge-msg[1], linkgit:git-pull[1], |
|
linkgit:gitattributes[5] |
|
|
|
|
|
Author |
|
------ |
|
Written by Junio C Hamano <junkio@cox.net> |
|
|
|
|
|
Documentation |
|
-------------- |
|
Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. |
|
|
|
GIT |
|
--- |
|
Part of the linkgit:git[7] suite
|
|
|