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[<key-id>]]
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.
73 Set the commit message to be used for the merge commit (in
76 If `--log` is specified, a shortlog of the commits being merged
77 will be appended to the specified message.
79 The 'git fmt-merge-msg' command can be
80 used to give a good default for automated 'git merge'
83 --[no-]rerere-autoupdate::
84 Allow the rerere mechanism to update the index with the
85 result of auto-conflict resolution if possible.
88 Abort the current conflict resolution process, and
89 try to reconstruct the pre-merge state.
91 If there were uncommitted worktree changes present when the merge
92 started, 'git merge --abort' will in some cases be unable to
93 reconstruct these changes. It is therefore recommended to always
94 commit or stash your changes before running 'git merge'.
96 'git merge --abort' is equivalent to 'git reset --merge' when
97 `MERGE_HEAD` is present.
100 Commits, usually other branch heads, to merge into our branch.
101 Specifying more than one commit will create a merge with
102 more than two parents (affectionately called an Octopus merge).
104 If no commit is given from the command line, merge the remote-tracking
105 branches that the current branch is configured to use as its upstream.
106 See also the configuration section of this manual page.
112 Before applying outside changes, you should get your own work in
113 good shape and committed locally, so it will not be clobbered if
114 there are conflicts. See also linkgit:git-stash[1].
115 'git pull' and 'git merge' will stop without doing anything when
116 local uncommitted changes overlap with files that 'git pull'/'git
117 merge' may need to update.
119 To avoid recording unrelated changes in the merge commit,
120 'git pull' and 'git merge' will also abort if there are any changes
121 registered in the index relative to the `HEAD` commit. (One
122 exception is when the changed index entries are in the state that
123 would result from the merge already.)
125 If all named commits are already ancestors of `HEAD`, 'git merge'
126 will exit early with the message "Already up-to-date."
131 Often the current branch head is an ancestor of the named commit.
132 This is the most common case especially when invoked from 'git
133 pull': you are tracking an upstream repository, you have committed
134 no local changes, and now you want to update to a newer upstream
135 revision. In this case, a new commit is not needed to store the
136 combined history; instead, the `HEAD` (along with the index) is
137 updated to point at the named commit, without creating an extra
140 This behavior can be suppressed with the `--no-ff` option.
145 Except in a fast-forward merge (see above), the branches to be
146 merged must be tied together by a merge commit that has both of them
149 A merged version reconciling the changes from all branches to be
150 merged is committed, and your `HEAD`, index, and working tree are
151 updated to it. It is possible to have modifications in the working
152 tree as long as they do not overlap; the update will preserve them.
154 When it is not obvious how to reconcile the changes, the following
157 1. The `HEAD` pointer stays the same.
158 2. The `MERGE_HEAD` ref is set to point to the other branch head.
159 3. Paths that merged cleanly are updated both in the index file and
160 in your working tree.
161 4. For conflicting paths, the index file records up to three
162 versions: stage 1 stores the version from the common ancestor,
163 stage 2 from `HEAD`, and stage 3 from `MERGE_HEAD` (you
164 can inspect the stages with `git ls-files -u`). The working
165 tree files contain the result of the "merge" program; i.e. 3-way
166 merge results with familiar conflict markers `<<<` `===` `>>>`.
167 5. No other changes are made. In particular, the local
168 modifications you had before you started merge will stay the
169 same and the index entries for them stay as they were,
170 i.e. matching `HEAD`.
172 If you tried a merge which resulted in complex conflicts and
173 want to start over, you can recover with `git merge --abort`.
178 When merging an annotated (and possibly signed) tag, Git always
179 creates a merge commit even if a fast-forward merge is possible, and
180 the commit message template is prepared with the tag message.
181 Additionally, if the tag is signed, the signature check is reported
182 as a comment in the message template. See also linkgit:git-tag[1].
184 When you want to just integrate with the work leading to the commit
185 that happens to be tagged, e.g. synchronizing with an upstream
186 release point, you may not want to make an unnecessary merge commit.
188 In such a case, you can "unwrap" the tag yourself before feeding it
189 to `git merge`, or pass `--ff-only` when you do not have any work on
195 git merge --ff-only v1.2.3
199 HOW CONFLICTS ARE PRESENTED
200 ---------------------------
202 During a merge, the working tree files are updated to reflect the result
203 of the merge. Among the changes made to the common ancestor's version,
204 non-overlapping ones (that is, you changed an area of the file while the
205 other side left that area intact, or vice versa) are incorporated in the
206 final result verbatim. When both sides made changes to the same area,
207 however, Git cannot randomly pick one side over the other, and asks you to
208 resolve it by leaving what both sides did to that area.
210 By default, Git uses the same style as the one used by the "merge" program
211 from the RCS suite to present such a conflicted hunk, like this:
214 Here are lines that are either unchanged from the common
215 ancestor, or cleanly resolved because only one side changed.
216 <<<<<<< yours:sample.txt
217 Conflict resolution is hard;
220 Git makes conflict resolution easy.
221 >>>>>>> theirs:sample.txt
222 And here is another line that is cleanly resolved or unmodified.
225 The area where a pair of conflicting changes happened is marked with markers
226 `<<<<<<<`, `=======`, and `>>>>>>>`. The part before the `=======`
227 is typically your side, and the part afterwards is typically their side.
229 The default format does not show what the original said in the conflicting
230 area. You cannot tell how many lines are deleted and replaced with
231 Barbie's remark on your side. The only thing you can tell is that your
232 side wants to say it is hard and you'd prefer to go shopping, while the
233 other side wants to claim it is easy.
235 An alternative style can be used by setting the "merge.conflictstyle"
236 configuration variable to "diff3". In "diff3" style, the above conflict
240 Here are lines that are either unchanged from the common
241 ancestor, or cleanly resolved because only one side changed.
242 <<<<<<< yours:sample.txt
243 Conflict resolution is hard;
246 Conflict resolution is hard.
248 Git makes conflict resolution easy.
249 >>>>>>> theirs:sample.txt
250 And here is another line that is cleanly resolved or unmodified.
253 In addition to the `<<<<<<<`, `=======`, and `>>>>>>>` markers, it uses
254 another `|||||||` marker that is followed by the original text. You can
255 tell that the original just stated a fact, and your side simply gave in to
256 that statement and gave up, while the other side tried to have a more
257 positive attitude. You can sometimes come up with a better resolution by
258 viewing the original.
261 HOW TO RESOLVE CONFLICTS
262 ------------------------
264 After seeing a conflict, you can do two things:
266 * Decide not to merge. The only clean-ups you need are to reset
267 the index file to the `HEAD` commit to reverse 2. and to clean
268 up working tree changes made by 2. and 3.; `git merge --abort`
269 can be used for this.
271 * Resolve the conflicts. Git will mark the conflicts in
272 the working tree. Edit the files into shape and
273 'git add' them to the index. Use 'git commit' to seal the deal.
275 You can work through the conflict with a number of tools:
277 * Use a mergetool. `git mergetool` to launch a graphical
278 mergetool which will work you through the merge.
280 * Look at the diffs. `git diff` will show a three-way diff,
281 highlighting changes from both the `HEAD` and `MERGE_HEAD`
284 * Look at the diffs from each branch. `git log --merge -p <path>`
285 will show diffs first for the `HEAD` version and then the
286 `MERGE_HEAD` version.
288 * Look at the originals. `git show :1:filename` shows the
289 common ancestor, `git show :2:filename` shows the `HEAD`
290 version, and `git show :3:filename` shows the `MERGE_HEAD`
297 * Merge branches `fixes` and `enhancements` on top of
298 the current branch, making an octopus merge:
300 ------------------------------------------------
301 $ git merge fixes enhancements
302 ------------------------------------------------
304 * Merge branch `obsolete` into the current branch, using `ours`
307 ------------------------------------------------
308 $ git merge -s ours obsolete
309 ------------------------------------------------
311 * Merge branch `maint` into the current branch, but do not make
312 a new commit automatically:
314 ------------------------------------------------
315 $ git merge --no-commit maint
316 ------------------------------------------------
318 This can be used when you want to include further changes to the
319 merge, or want to write your own merge commit message.
321 You should refrain from abusing this option to sneak substantial
322 changes into a merge commit. Small fixups like bumping
323 release/version name would be acceptable.
326 include::merge-strategies.txt[]
330 include::merge-config.txt[]
332 branch.<name>.mergeoptions::
333 Sets default options for merging into branch <name>. The syntax and
334 supported options are the same as those of 'git merge', but option
335 values containing whitespace characters are currently not supported.
339 linkgit:git-fmt-merge-msg[1], linkgit:git-pull[1],
340 linkgit:gitattributes[5],
341 linkgit:git-reset[1],
342 linkgit:git-diff[1], linkgit:git-ls-files[1],
343 linkgit:git-add[1], linkgit:git-rm[1],
344 linkgit:git-mergetool[1]
348 Part of the linkgit:git[1] suite
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