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>] [-S[<keyid>]]
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 non-trivial uncommitted changes is
60 discouraged: while possible, it may leave you in a state that is hard to
61 back out of in the case of a conflict.
66 include::merge-options.txt[]
69 --gpg-sign[=<keyid>]::
70 GPG-sign the resulting merge commit. The `keyid` argument is
71 optional and defaults to the committer identity; if specified,
72 it must be stuck to the option without a space.
75 Set the commit message to be used for the merge commit (in
78 If `--log` is specified, a shortlog of the commits being merged
79 will be appended to the specified message.
81 The 'git fmt-merge-msg' command can be
82 used to give a good default for automated 'git merge'
83 invocations. The automated message can include the branch description.
85 --[no-]rerere-autoupdate::
86 Allow the rerere mechanism to update the index with the
87 result of auto-conflict resolution if possible.
90 Abort the current conflict resolution process, and
91 try to reconstruct the pre-merge state.
93 If there were uncommitted worktree changes present when the merge
94 started, 'git merge --abort' will in some cases be unable to
95 reconstruct these changes. It is therefore recommended to always
96 commit or stash your changes before running 'git merge'.
98 'git merge --abort' is equivalent to 'git reset --merge' when
99 `MERGE_HEAD` is present.
102 Commits, usually other branch heads, to merge into our branch.
103 Specifying more than one commit will create a merge with
104 more than two parents (affectionately called an Octopus merge).
106 If no commit is given from the command line, merge the remote-tracking
107 branches that the current branch is configured to use as its upstream.
108 See also the configuration section of this manual page.
110 When `FETCH_HEAD` (and no other commit) is specified, the branches
111 recorded in the `.git/FETCH_HEAD` file by the previous invocation
112 of `git fetch` for merging are merged to the current branch.
118 Before applying outside changes, you should get your own work in
119 good shape and committed locally, so it will not be clobbered if
120 there are conflicts. See also linkgit:git-stash[1].
121 'git pull' and 'git merge' will stop without doing anything when
122 local uncommitted changes overlap with files that 'git pull'/'git
123 merge' may need to update.
125 To avoid recording unrelated changes in the merge commit,
126 'git pull' and 'git merge' will also abort if there are any changes
127 registered in the index relative to the `HEAD` commit. (One
128 exception is when the changed index entries are in the state that
129 would result from the merge already.)
131 If all named commits are already ancestors of `HEAD`, 'git merge'
132 will exit early with the message "Already up-to-date."
137 Often the current branch head is an ancestor of the named commit.
138 This is the most common case especially when invoked from 'git
139 pull': you are tracking an upstream repository, you have committed
140 no local changes, and now you want to update to a newer upstream
141 revision. In this case, a new commit is not needed to store the
142 combined history; instead, the `HEAD` (along with the index) is
143 updated to point at the named commit, without creating an extra
146 This behavior can be suppressed with the `--no-ff` option.
151 Except in a fast-forward merge (see above), the branches to be
152 merged must be tied together by a merge commit that has both of them
155 A merged version reconciling the changes from all branches to be
156 merged is committed, and your `HEAD`, index, and working tree are
157 updated to it. It is possible to have modifications in the working
158 tree as long as they do not overlap; the update will preserve them.
160 When it is not obvious how to reconcile the changes, the following
163 1. The `HEAD` pointer stays the same.
164 2. The `MERGE_HEAD` ref is set to point to the other branch head.
165 3. Paths that merged cleanly are updated both in the index file and
166 in your working tree.
167 4. For conflicting paths, the index file records up to three
168 versions: stage 1 stores the version from the common ancestor,
169 stage 2 from `HEAD`, and stage 3 from `MERGE_HEAD` (you
170 can inspect the stages with `git ls-files -u`). The working
171 tree files contain the result of the "merge" program; i.e. 3-way
172 merge results with familiar conflict markers `<<<` `===` `>>>`.
173 5. No other changes are made. In particular, the local
174 modifications you had before you started merge will stay the
175 same and the index entries for them stay as they were,
176 i.e. matching `HEAD`.
178 If you tried a merge which resulted in complex conflicts and
179 want to start over, you can recover with `git merge --abort`.
184 When merging an annotated (and possibly signed) tag, Git always
185 creates a merge commit even if a fast-forward merge is possible, and
186 the commit message template is prepared with the tag message.
187 Additionally, if the tag is signed, the signature check is reported
188 as a comment in the message template. See also linkgit:git-tag[1].
190 When you want to just integrate with the work leading to the commit
191 that happens to be tagged, e.g. synchronizing with an upstream
192 release point, you may not want to make an unnecessary merge commit.
194 In such a case, you can "unwrap" the tag yourself before feeding it
195 to `git merge`, or pass `--ff-only` when you do not have any work on
201 git merge --ff-only v1.2.3
205 HOW CONFLICTS ARE PRESENTED
206 ---------------------------
208 During a merge, the working tree files are updated to reflect the result
209 of the merge. Among the changes made to the common ancestor's version,
210 non-overlapping ones (that is, you changed an area of the file while the
211 other side left that area intact, or vice versa) are incorporated in the
212 final result verbatim. When both sides made changes to the same area,
213 however, Git cannot randomly pick one side over the other, and asks you to
214 resolve it by leaving what both sides did to that area.
216 By default, Git uses the same style as the one used by the "merge" program
217 from the RCS suite to present such a conflicted hunk, like this:
220 Here are lines that are either unchanged from the common
221 ancestor, or cleanly resolved because only one side changed.
222 <<<<<<< yours:sample.txt
223 Conflict resolution is hard;
226 Git makes conflict resolution easy.
227 >>>>>>> theirs:sample.txt
228 And here is another line that is cleanly resolved or unmodified.
231 The area where a pair of conflicting changes happened is marked with markers
232 `<<<<<<<`, `=======`, and `>>>>>>>`. The part before the `=======`
233 is typically your side, and the part afterwards is typically their side.
235 The default format does not show what the original said in the conflicting
236 area. You cannot tell how many lines are deleted and replaced with
237 Barbie's remark on your side. The only thing you can tell is that your
238 side wants to say it is hard and you'd prefer to go shopping, while the
239 other side wants to claim it is easy.
241 An alternative style can be used by setting the "merge.conflictStyle"
242 configuration variable to "diff3". In "diff3" style, the above conflict
246 Here are lines that are either unchanged from the common
247 ancestor, or cleanly resolved because only one side changed.
248 <<<<<<< yours:sample.txt
249 Conflict resolution is hard;
252 Conflict resolution is hard.
254 Git makes conflict resolution easy.
255 >>>>>>> theirs:sample.txt
256 And here is another line that is cleanly resolved or unmodified.
259 In addition to the `<<<<<<<`, `=======`, and `>>>>>>>` markers, it uses
260 another `|||||||` marker that is followed by the original text. You can
261 tell that the original just stated a fact, and your side simply gave in to
262 that statement and gave up, while the other side tried to have a more
263 positive attitude. You can sometimes come up with a better resolution by
264 viewing the original.
267 HOW TO RESOLVE CONFLICTS
268 ------------------------
270 After seeing a conflict, you can do two things:
272 * Decide not to merge. The only clean-ups you need are to reset
273 the index file to the `HEAD` commit to reverse 2. and to clean
274 up working tree changes made by 2. and 3.; `git merge --abort`
275 can be used for this.
277 * Resolve the conflicts. Git will mark the conflicts in
278 the working tree. Edit the files into shape and
279 'git add' them to the index. Use 'git commit' to seal the deal.
281 You can work through the conflict with a number of tools:
283 * Use a mergetool. `git mergetool` to launch a graphical
284 mergetool which will work you through the merge.
286 * Look at the diffs. `git diff` will show a three-way diff,
287 highlighting changes from both the `HEAD` and `MERGE_HEAD`
290 * Look at the diffs from each branch. `git log --merge -p <path>`
291 will show diffs first for the `HEAD` version and then the
292 `MERGE_HEAD` version.
294 * Look at the originals. `git show :1:filename` shows the
295 common ancestor, `git show :2:filename` shows the `HEAD`
296 version, and `git show :3:filename` shows the `MERGE_HEAD`
303 * Merge branches `fixes` and `enhancements` on top of
304 the current branch, making an octopus merge:
306 ------------------------------------------------
307 $ git merge fixes enhancements
308 ------------------------------------------------
310 * Merge branch `obsolete` into the current branch, using `ours`
313 ------------------------------------------------
314 $ git merge -s ours obsolete
315 ------------------------------------------------
317 * Merge branch `maint` into the current branch, but do not make
318 a new commit automatically:
320 ------------------------------------------------
321 $ git merge --no-commit maint
322 ------------------------------------------------
324 This can be used when you want to include further changes to the
325 merge, or want to write your own merge commit message.
327 You should refrain from abusing this option to sneak substantial
328 changes into a merge commit. Small fixups like bumping
329 release/version name would be acceptable.
332 include::merge-strategies.txt[]
336 include::merge-config.txt[]
338 branch.<name>.mergeOptions::
339 Sets default options for merging into branch <name>. The syntax and
340 supported options are the same as those of 'git merge', but option
341 values containing whitespace characters are currently not supported.
345 linkgit:git-fmt-merge-msg[1], linkgit:git-pull[1],
346 linkgit:gitattributes[5],
347 linkgit:git-reset[1],
348 linkgit:git-diff[1], linkgit:git-ls-files[1],
349 linkgit:git-add[1], linkgit:git-rm[1],
350 linkgit:git-mergetool[1]
354 Part of the linkgit:git[1] suite
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