]> git.ipfire.org Git - thirdparty/git.git/blame - Documentation/merge-strategies.txt
Merge branch 'js/t3404-typofix' into maint
[thirdparty/git.git] / Documentation / merge-strategies.txt
CommitLineData
bb73d73c
JL
1MERGE STRATEGIES
2----------------
3
3c3e6f56 4The merge mechanism (`git merge` and `git pull` commands) allows the
566c5111
JH
5backend 'merge strategies' to be chosen with `-s` option. Some strategies
6can also take their own options, which can be passed by giving `-X<option>`
3c3e6f56 7arguments to `git merge` and/or `git pull`.
566c5111 8
bb73d73c
JL
9resolve::
10 This can only resolve two heads (i.e. the current branch
4fa535a1 11 and another branch you pulled from) using a 3-way merge
bb73d73c
JL
12 algorithm. It tries to carefully detect criss-cross
13 merge ambiguities and is considered generally safe and
9688a882 14 fast.
bb73d73c
JL
15
16recursive::
4fa535a1
WC
17 This can only resolve two heads using a 3-way merge
18 algorithm. When there is more than one common
19 ancestor that can be used for 3-way merge, it creates a
9688a882 20 merged tree of the common ancestors and uses that as
bb73d73c
JL
21 the reference tree for the 3-way merge. This has been
22 reported to result in fewer merge conflicts without
13f72a1d 23 causing mismerges by tests done on actual merge commits
bb73d73c
JL
24 taken from Linux 2.6 kernel development history.
25 Additionally this can detect and handle merges involving
85b46030
BP
26 renames, but currently cannot make use of detected
27 copies. This is the default merge strategy when pulling
28 or merging one branch.
566c5111
JH
29+
30The 'recursive' strategy can take the following options:
31
32ours;;
33 This option forces conflicting hunks to be auto-resolved cleanly by
34 favoring 'our' version. Changes from the other tree that do not
35 conflict with our side are reflected to the merge result.
a944af1d 36 For a binary file, the entire contents are taken from our side.
566c5111
JH
37+
38This should not be confused with the 'ours' merge strategy, which does not
39even look at what the other tree contains at all. It discards everything
40the other tree did, declaring 'our' history contains all that happened in it.
41
42theirs;;
c25d98b2 43 This is the opposite of 'ours'; note that, unlike 'ours', there is
bd9958c3 44 no 'theirs' merge strategy to confuse this merge option with.
566c5111 45
58a1ece4
JF
46patience;;
47 With this option, 'merge-recursive' spends a little extra time
48 to avoid mismerges that sometimes occur due to unimportant
49 matching lines (e.g., braces from distinct functions). Use
50 this when the branches to be merged have diverged wildly.
51 See also linkgit:git-diff[1] `--patience`.
52
4db4f0fb
JK
53diff-algorithm=[patience|minimal|histogram|myers];;
54 Tells 'merge-recursive' to use a different diff algorithm, which
55 can help avoid mismerges that occur due to unimportant matching
56 lines (such as braces from distinct functions). See also
57 linkgit:git-diff[1] `--diff-algorithm`.
58
4e5dd044
JF
59ignore-space-change;;
60ignore-all-space;;
61ignore-space-at-eol;;
e9282f02 62ignore-cr-at-eol;;
4e5dd044
JF
63 Treats lines with the indicated type of whitespace change as
64 unchanged for the sake of a three-way merge. Whitespace
65 changes mixed with other changes to a line are not ignored.
e9282f02
JH
66 See also linkgit:git-diff[1] `-b`, `-w`,
67 `--ignore-space-at-eol`, and `--ignore-cr-at-eol`.
4e5dd044
JF
68+
69* If 'their' version only introduces whitespace changes to a line,
70 'our' version is used;
71* If 'our' version introduces whitespace changes but 'their'
72 version includes a substantial change, 'their' version is used;
73* Otherwise, the merge proceeds in the usual way.
74
7610fa57
JN
75renormalize;;
76 This runs a virtual check-out and check-in of all three stages
77 of a file when resolving a three-way merge. This option is
78 meant to be used when merging branches with different clean
79 filters or end-of-line normalization rules. See "Merging
80 branches with differing checkin/checkout attributes" in
81 linkgit:gitattributes[5] for details.
82
83no-renormalize;;
84 Disables the `renormalize` option. This overrides the
85 `merge.renormalize` configuration variable.
86
d2b11eca 87no-renames;;
85b46030
BP
88 Turn off rename detection. This overrides the `merge.renames`
89 configuration variable.
d2b11eca
FGA
90 See also linkgit:git-diff[1] `--no-renames`.
91
1b47ad16 92find-renames[=<n>];;
83837ec0 93 Turn on rename detection, optionally setting the similarity
85b46030
BP
94 threshold. This is the default. This overrides the
95 'merge.renames' configuration variable.
1b47ad16
FGA
96 See also linkgit:git-diff[1] `--find-renames`.
97
10ae7526 98rename-threshold=<n>;;
1b47ad16 99 Deprecated synonym for `find-renames=<n>`.
10ae7526 100
62b4698e 101subtree[=<path>];;
566c5111
JH
102 This option is a more advanced form of 'subtree' strategy, where
103 the strategy makes a guess on how two trees must be shifted to
104 match with each other when merging. Instead, the specified path
105 is prefixed (or stripped from the beginning) to make the shape of
106 two trees to match.
bb73d73c
JL
107
108octopus::
4fa535a1
WC
109 This resolves cases with more than two heads, but refuses to do
110 a complex merge that needs manual resolution. It is
bb73d73c
JL
111 primarily meant to be used for bundling topic branch
112 heads together. This is the default merge strategy when
4fa535a1 113 pulling or merging more than one branch.
bb73d73c
JL
114
115ours::
d4cbaa12
TR
116 This resolves any number of heads, but the resulting tree of the
117 merge is always that of the current branch head, effectively
118 ignoring all changes from all other branches. It is meant to
bb73d73c 119 be used to supersede old development history of side
566c5111
JH
120 branches. Note that this is different from the -Xours option to
121 the 'recursive' merge strategy.
02b00e16
MV
122
123subtree::
124 This is a modified recursive strategy. When merging trees A and
125 B, if B corresponds to a subtree of A, B is first adjusted to
126 match the tree structure of A, instead of reading the trees at
127 the same level. This adjustment is also done to the common
128 ancestor tree.
c5665000 129
130With the strategies that use 3-way merge (including the default, 'recursive'),
131if a change is made on both branches, but later reverted on one of the
132branches, that change will be present in the merged result; some people find
133this behavior confusing. It occurs because only the heads and the merge base
134are considered when performing a merge, not the individual commits. The merge
135algorithm therefore considers the reverted change as no change at all, and
136substitutes the changed version instead.