fetch: opportunistically update tracking refs
[git/git.git] / Documentation / pull-fetch-param.txt
1 <repository>::
2 The "remote" repository that is the source of a fetch
3 or pull operation. This parameter can be either a URL
4 (see the section <<URLS,GIT URLS>> below) or the name
5 of a remote (see the section <<REMOTES,REMOTES>> below).
6
7 ifndef::git-pull[]
8 <group>::
9 A name referring to a list of repositories as the value
10 of remotes.<group> in the configuration file.
11 (See linkgit:git-config[1]).
12 endif::git-pull[]
13
14 <refspec>::
15 The format of a <refspec> parameter is an optional plus
16 `+`, followed by the source ref <src>, followed
17 by a colon `:`, followed by the destination ref <dst>.
18 +
19 The remote ref that matches <src>
20 is fetched, and if <dst> is not empty string, the local
21 ref that matches it is fast-forwarded using <src>.
22 If the optional plus `+` is used, the local ref
23 is updated even if it does not result in a fast-forward
24 update.
25 +
26 [NOTE]
27 If the remote branch from which you want to pull is
28 modified in non-linear ways such as being rewound and
29 rebased frequently, then a pull will attempt a merge with
30 an older version of itself, likely conflict, and fail.
31 It is under these conditions that you would want to use
32 the `+` sign to indicate non-fast-forward updates will
33 be needed. There is currently no easy way to determine
34 or declare that a branch will be made available in a
35 repository with this behavior; the pulling user simply
36 must know this is the expected usage pattern for a branch.
37 +
38 [NOTE]
39 You never do your own development on branches that appear
40 on the right hand side of a <refspec> colon on `Pull:` lines;
41 they are to be updated by 'git fetch'. If you intend to do
42 development derived from a remote branch `B`, have a `Pull:`
43 line to track it (i.e. `Pull: B:remote-B`), and have a separate
44 branch `my-B` to do your development on top of it. The latter
45 is created by `git branch my-B remote-B` (or its equivalent `git
46 checkout -b my-B remote-B`). Run `git fetch` to keep track of
47 the progress of the remote side, and when you see something new
48 on the remote branch, merge it into your development branch with
49 `git pull . remote-B`, while you are on `my-B` branch.
50 +
51 [NOTE]
52 There is a difference between listing multiple <refspec>
53 directly on 'git pull' command line and having multiple
54 `Pull:` <refspec> lines for a <repository> and running
55 'git pull' command without any explicit <refspec> parameters.
56 <refspec> listed explicitly on the command line are always
57 merged into the current branch after fetching. In other words,
58 if you list more than one remote refs, you would be making
59 an Octopus. While 'git pull' run without any explicit <refspec>
60 parameter takes default <refspec>s from `Pull:` lines, it
61 merges only the first <refspec> found into the current branch,
62 after fetching all the remote refs. This is because making an
63 Octopus from remote refs is rarely done, while keeping track
64 of multiple remote heads in one-go by fetching more than one
65 is often useful.
66 +
67 Some short-cut notations are also supported.
68 +
69 * `tag <tag>` means the same as `refs/tags/<tag>:refs/tags/<tag>`;
70 it requests fetching everything up to the given tag.
71 ifndef::git-pull[]
72 * A parameter <ref> without a colon fetches that ref into FETCH_HEAD,
73 endif::git-pull[]
74 ifdef::git-pull[]
75 * A parameter <ref> without a colon merges <ref> into the current
76 branch,
77 endif::git-pull[]
78 and updates the remote-tracking branches (if any).