6 git-merge - Join two or more development histories together
12 'git merge' [-n] [--stat] [--no-commit] [--squash] [--[no-]edit]
13 [-s <strategy>] [-X <strategy-option>]
14 [--[no-]rerere-autoupdate] [-m <msg>] [<commit>...]
15 'git merge' <msg> HEAD <commit>...
20 Incorporates changes from the named commits (since the time their
21 histories diverged from the current branch) into the current
22 branch. This command is used by 'git pull' to incorporate changes
23 from another repository and can be used by hand to merge changes
24 from one branch into another.
26 Assume the following history exists and the current branch is
35 Then "`git merge topic`" will replay the changes made on the
36 `topic` branch since it diverged from `master` (i.e., `E`) until
37 its current commit (`C`) on top of `master`, and record the result
38 in a new commit along with the names of the two parent commits and
39 a log message from the user describing the changes.
44 D---E---F---G---H master
47 The second syntax (<msg> `HEAD` <commit>...) is supported for
48 historical reasons. Do not use it from the command line or in
49 new scripts. It is the same as `git merge -m <msg> <commit>...`.
51 The third syntax ("`git merge --abort`") can only be run after the
52 merge has resulted in conflicts. 'git merge --abort' will abort the
53 merge process and try to reconstruct the pre-merge state. However,
54 if there were uncommitted changes when the merge started (and
55 especially if those changes were further modified after the merge
56 was started), 'git merge --abort' will in some cases be unable to
57 reconstruct the original (pre-merge) changes. Therefore:
59 *Warning*: Running 'git merge' with uncommitted changes is
60 discouraged: while possible, it leaves you in a state that is hard to
61 back out of in the case of a conflict.
66 include::merge-options.txt[]
69 Set the commit message to be used for the merge commit (in
72 If `--log` is specified, a shortlog of the commits being merged
73 will be appended to the specified message.
75 The 'git fmt-merge-msg' command can be
76 used to give a good default for automated 'git merge'
80 --no-rerere-autoupdate::
81 Allow the rerere mechanism to update the index with the
82 result of auto-conflict resolution if possible.
85 Abort the current conflict resolution process, and
86 try to reconstruct the pre-merge state.
88 If there were uncommitted worktree changes present when the merge
89 started, 'git merge --abort' will in some cases be unable to
90 reconstruct these changes. It is therefore recommended to always
91 commit or stash your changes before running 'git merge'.
93 'git merge --abort' is equivalent to 'git reset --merge' when
94 `MERGE_HEAD` is present.
97 Commits, usually other branch heads, to merge into our branch.
98 Specifying more than one commit will create a merge with
99 more than two parents (affectionately called an Octopus merge).
101 If no commit is given from the command line, and if `merge.defaultToUpstream`
102 configuration variable is set, merge the remote-tracking branches
103 that the current branch is configured to use as its upstream.
104 See also the configuration section of this manual page.
110 Before applying outside changes, you should get your own work in
111 good shape and committed locally, so it will not be clobbered if
112 there are conflicts. See also linkgit:git-stash[1].
113 'git pull' and 'git merge' will stop without doing anything when
114 local uncommitted changes overlap with files that 'git pull'/'git
115 merge' may need to update.
117 To avoid recording unrelated changes in the merge commit,
118 'git pull' and 'git merge' will also abort if there are any changes
119 registered in the index relative to the `HEAD` commit. (One
120 exception is when the changed index entries are in the state that
121 would result from the merge already.)
123 If all named commits are already ancestors of `HEAD`, 'git merge'
124 will exit early with the message "Already up-to-date."
129 Often the current branch head is an ancestor of the named commit.
130 This is the most common case especially when invoked from 'git
131 pull': you are tracking an upstream repository, you have committed
132 no local changes, and now you want to update to a newer upstream
133 revision. In this case, a new commit is not needed to store the
134 combined history; instead, the `HEAD` (along with the index) is
135 updated to point at the named commit, without creating an extra
138 This behavior can be suppressed with the `--no-ff` option.
143 Except in a fast-forward merge (see above), the branches to be
144 merged must be tied together by a merge commit that has both of them
147 A merged version reconciling the changes from all branches to be
148 merged is committed, and your `HEAD`, index, and working tree are
149 updated to it. It is possible to have modifications in the working
150 tree as long as they do not overlap; the update will preserve them.
152 When it is not obvious how to reconcile the changes, the following
155 1. The `HEAD` pointer stays the same.
156 2. The `MERGE_HEAD` ref is set to point to the other branch head.
157 3. Paths that merged cleanly are updated both in the index file and
158 in your working tree.
159 4. For conflicting paths, the index file records up to three
160 versions: stage 1 stores the version from the common ancestor,
161 stage 2 from `HEAD`, and stage 3 from `MERGE_HEAD` (you
162 can inspect the stages with `git ls-files -u`). The working
163 tree files contain the result of the "merge" program; i.e. 3-way
164 merge results with familiar conflict markers `<<<` `===` `>>>`.
165 5. No other changes are made. In particular, the local
166 modifications you had before you started merge will stay the
167 same and the index entries for them stay as they were,
168 i.e. matching `HEAD`.
170 If you tried a merge which resulted in complex conflicts and
171 want to start over, you can recover with `git merge --abort`.
176 When merging an annotated (and possibly signed) tag, Git always
177 creates a merge commit even if a fast-forward merge is possible, and
178 the commit message template is prepared with the tag message.
179 Additionally, if the tag is signed, the signature check is reported
180 as a comment in the message template. See also linkgit:git-tag[1].
182 When you want to just integrate with the work leading to the commit
183 that happens to be tagged, e.g. synchronizing with an upstream
184 release point, you may not want to make an unnecessary merge commit.
186 In such a case, you can "unwrap" the tag yourself before feeding it
187 to `git merge`, or pass `--ff-only` when you do not have any work on
193 git merge --ff-only v1.2.3
197 HOW CONFLICTS ARE PRESENTED
198 ---------------------------
200 During a merge, the working tree files are updated to reflect the result
201 of the merge. Among the changes made to the common ancestor's version,
202 non-overlapping ones (that is, you changed an area of the file while the
203 other side left that area intact, or vice versa) are incorporated in the
204 final result verbatim. When both sides made changes to the same area,
205 however, Git cannot randomly pick one side over the other, and asks you to
206 resolve it by leaving what both sides did to that area.
208 By default, Git uses the same style as the one used by the "merge" program
209 from the RCS suite to present such a conflicted hunk, like this:
212 Here are lines that are either unchanged from the common
213 ancestor, or cleanly resolved because only one side changed.
214 <<<<<<< yours:sample.txt
215 Conflict resolution is hard;
218 Git makes conflict resolution easy.
219 >>>>>>> theirs:sample.txt
220 And here is another line that is cleanly resolved or unmodified.
223 The area where a pair of conflicting changes happened is marked with markers
224 `<<<<<<<`, `=======`, and `>>>>>>>`. The part before the `=======`
225 is typically your side, and the part afterwards is typically their side.
227 The default format does not show what the original said in the conflicting
228 area. You cannot tell how many lines are deleted and replaced with
229 Barbie's remark on your side. The only thing you can tell is that your
230 side wants to say it is hard and you'd prefer to go shopping, while the
231 other side wants to claim it is easy.
233 An alternative style can be used by setting the "merge.conflictstyle"
234 configuration variable to "diff3". In "diff3" style, the above conflict
238 Here are lines that are either unchanged from the common
239 ancestor, or cleanly resolved because only one side changed.
240 <<<<<<< yours:sample.txt
241 Conflict resolution is hard;
244 Conflict resolution is hard.
246 Git makes conflict resolution easy.
247 >>>>>>> theirs:sample.txt
248 And here is another line that is cleanly resolved or unmodified.
251 In addition to the `<<<<<<<`, `=======`, and `>>>>>>>` markers, it uses
252 another `|||||||` marker that is followed by the original text. You can
253 tell that the original just stated a fact, and your side simply gave in to
254 that statement and gave up, while the other side tried to have a more
255 positive attitude. You can sometimes come up with a better resolution by
256 viewing the original.
259 HOW TO RESOLVE CONFLICTS
260 ------------------------
262 After seeing a conflict, you can do two things:
264 * Decide not to merge. The only clean-ups you need are to reset
265 the index file to the `HEAD` commit to reverse 2. and to clean
266 up working tree changes made by 2. and 3.; `git merge --abort`
267 can be used for this.
269 * Resolve the conflicts. Git will mark the conflicts in
270 the working tree. Edit the files into shape and
271 'git add' them to the index. Use 'git commit' to seal the deal.
273 You can work through the conflict with a number of tools:
275 * Use a mergetool. `git mergetool` to launch a graphical
276 mergetool which will work you through the merge.
278 * Look at the diffs. `git diff` will show a three-way diff,
279 highlighting changes from both the `HEAD` and `MERGE_HEAD`
282 * Look at the diffs from each branch. `git log --merge -p <path>`
283 will show diffs first for the `HEAD` version and then the
284 `MERGE_HEAD` version.
286 * Look at the originals. `git show :1:filename` shows the
287 common ancestor, `git show :2:filename` shows the `HEAD`
288 version, and `git show :3:filename` shows the `MERGE_HEAD`
295 * Merge branches `fixes` and `enhancements` on top of
296 the current branch, making an octopus merge:
298 ------------------------------------------------
299 $ git merge fixes enhancements
300 ------------------------------------------------
302 * Merge branch `obsolete` into the current branch, using `ours`
305 ------------------------------------------------
306 $ git merge -s ours obsolete
307 ------------------------------------------------
309 * Merge branch `maint` into the current branch, but do not make
310 a new commit automatically:
312 ------------------------------------------------
313 $ git merge --no-commit maint
314 ------------------------------------------------
316 This can be used when you want to include further changes to the
317 merge, or want to write your own merge commit message.
319 You should refrain from abusing this option to sneak substantial
320 changes into a merge commit. Small fixups like bumping
321 release/version name would be acceptable.
324 include::merge-strategies.txt[]
328 include::merge-config.txt[]
330 branch.<name>.mergeoptions::
331 Sets default options for merging into branch <name>. The syntax and
332 supported options are the same as those of 'git merge', but option
333 values containing whitespace characters are currently not supported.
337 linkgit:git-fmt-merge-msg[1], linkgit:git-pull[1],
338 linkgit:gitattributes[5],
339 linkgit:git-reset[1],
340 linkgit:git-diff[1], linkgit:git-ls-files[1],
341 linkgit:git-add[1], linkgit:git-rm[1],
342 linkgit:git-mergetool[1]
346 Part of the linkgit:git[1] suite
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