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Diffstat (limited to 'contrib/subtree/git-subtree.txt')
| -rw-r--r-- | contrib/subtree/git-subtree.txt | 192 |
1 files changed, 92 insertions, 100 deletions
diff --git a/contrib/subtree/git-subtree.txt b/contrib/subtree/git-subtree.txt index 0db02fe..9cddfa2 100644 --- a/contrib/subtree/git-subtree.txt +++ b/contrib/subtree/git-subtree.txt @@ -9,13 +9,14 @@ git-subtree - Merge subtrees together and split repository into subtrees SYNOPSIS -------- [verse] -'git subtree' add -P <prefix> <commit> -'git subtree' add -P <prefix> <repository> <ref> -'git subtree' pull -P <prefix> <repository> <ref> -'git subtree' push -P <prefix> <repository> <ref> -'git subtree' merge -P <prefix> <commit> -'git subtree' split -P <prefix> [OPTIONS] [<commit>] +'git subtree' [<options>] -P <prefix> add <local-commit> +'git subtree' [<options>] -P <prefix> add <repository> <remote-ref> +'git subtree' [<options>] -P <prefix> merge <local-commit> +'git subtree' [<options>] -P <prefix> split [<local-commit>] +[verse] +'git subtree' [<options>] -P <prefix> pull <repository> <remote-ref> +'git subtree' [<options>] -P <prefix> push <repository> <refspec> DESCRIPTION ----------- @@ -28,7 +29,7 @@ as a subdirectory of your application. Subtrees are not to be confused with submodules, which are meant for the same task. Unlike submodules, subtrees do not need any special -constructions (like .gitmodules files or gitlinks) be present in +constructions (like '.gitmodules' files or gitlinks) be present in your repository, and do not force end-users of your repository to do anything special or to understand how subtrees work. A subtree is just a subdirectory that can be @@ -59,70 +60,71 @@ project as much as possible. That is, if you make a change that affects both the library and the main application, commit it in two pieces. That way, when you split the library commits out later, their descriptions will still make sense. But if this -isn't important to you, it's not *necessary*. git subtree will +isn't important to you, it's not *necessary*. 'git subtree' will simply leave out the non-library-related parts of the commit when it splits it out into the subproject later. COMMANDS -------- -add:: +add <local-commit>:: +add <repository> <remote-ref>:: Create the <prefix> subtree by importing its contents - from the given <commit> or <repository> and remote <ref>. + from the given <local-commit> or <repository> and <remote-ref>. A new commit is created automatically, joining the imported - project's history with your own. With '--squash', imports + project's history with your own. With '--squash', import only a single commit from the subproject, rather than its entire history. -merge:: - Merge recent changes up to <commit> into the <prefix> +merge <local-commit>:: + Merge recent changes up to <local-commit> into the <prefix> subtree. As with normal 'git merge', this doesn't remove your own local changes; it just merges those - changes into the latest <commit>. With '--squash', - creates only one commit that contains all the changes, + changes into the latest <local-commit>. With '--squash', + create only one commit that contains all the changes, rather than merging in the entire history. + If you use '--squash', the merge direction doesn't always have to be forward; you can use this command to go back in time from v2.5 to v2.4, for example. If your merge introduces a conflict, you can resolve it in the usual ways. - -pull:: - Exactly like 'merge', but parallels 'git pull' in that - it fetches the given ref from the specified remote - repository. - -push:: - Does a 'split' (see below) using the <prefix> supplied - and then does a 'git push' to push the result to the - repository and ref. This can be used to push your - subtree to different branches of the remote repository. - -split:: + +split [<local-commit>]:: Extract a new, synthetic project history from the - history of the <prefix> subtree. The new history + history of the <prefix> subtree of <local-commit>, or of + HEAD if no <local-commit> is given. The new history includes only the commits (including merges) that affected <prefix>, and each of those commits now has the contents of <prefix> at the root of the project instead of in a subdirectory. Thus, the newly created history is suitable for export as a separate git repository. + -After splitting successfully, a single commit id is printed to stdout. +After splitting successfully, a single commit ID is printed to stdout. This corresponds to the HEAD of the newly created tree, which you can manipulate however you want. + Repeated splits of exactly the same history are guaranteed to be -identical (i.e. to produce the same commit ids). Because of this, if -you add new commits and then re-split, the new commits will be attached -as commits on top of the history you generated last time, so 'git merge' -and friends will work as expected. -+ -Note that if you use '--squash' when you merge, you should usually not -just '--rejoin' when you split. +identical (i.e. to produce the same commit IDs) as long as the +settings passed to 'split' (such as '--annotate') are the same. +Because of this, if you add new commits and then re-split, the new +commits will be attached as commits on top of the history you +generated last time, so 'git merge' and friends will work as expected. +pull <repository> <remote-ref>:: + Exactly like 'merge', but parallels 'git pull' in that + it fetches the given ref from the specified remote + repository. + +push <repository> [+][<local-commit>:]<remote-ref>:: + Does a 'split' using the <prefix> subtree of <local-commit> + and then does a 'git push' to push the result to the + <repository> and <remote-ref>. This can be used to push your + subtree to different branches of the remote repository. Just + as with 'split', if no <local-commit> is given, then HEAD is + used. The optional leading '+' is ignored. -OPTIONS -------- +OPTIONS FOR ALL COMMANDS +------------------------ -q:: --quiet:: Suppress unnecessary output messages on stderr. @@ -137,21 +139,16 @@ OPTIONS want to manipulate. This option is mandatory for all commands. --m <message>:: ---message=<message>:: - This option is only valid for add, merge, pull, and split --rejoin. - Specify <message> as the commit message for the merge commit. - +OPTIONS FOR 'add' AND 'merge' (ALSO: 'pull', 'split --rejoin', AND 'push --rejoin') +----------------------------------------------------------------------------------- +These options for 'add' and 'merge' may also be given to 'pull' (which +wraps 'merge'), 'split --rejoin' (which wraps either 'add' or 'merge' +as appropriate), and 'push --rejoin' (which wraps 'split --rejoin'). -OPTIONS FOR add, merge, and pull --------------------------------- --squash:: - This option is only valid for add, merge, and pull - commands. -+ -Instead of merging the entire history from the subtree project, produce -only a single commit that contains all the differences you want to -merge, and then merge that new commit into your project. + Instead of merging the entire history from the subtree project, produce + only a single commit that contains all the differences you want to + merge, and then merge that new commit into your project. + Using this option helps to reduce log clutter. People rarely want to see every change that happened between v1.0 and v1.1 of the library they're @@ -174,57 +171,53 @@ Whether or not you use '--squash', changes made in your local repository remain intact and can be later split and send upstream to the subproject. +-m <message>:: +--message=<message>:: + Specify <message> as the commit message for the merge commit. + +OPTIONS FOR 'split' (ALSO: 'push') +---------------------------------- +These options for 'split' may also be given to 'push' (which wraps +'split'). -OPTIONS FOR split ------------------ --annotate=<annotation>:: - This option is only valid for the split command. -+ -When generating synthetic history, add <annotation> as a prefix to each -commit message. Since we're creating new commits with the same commit -message, but possibly different content, from the original commits, this -can help to differentiate them and avoid confusion. + When generating synthetic history, add <annotation> as a prefix to each + commit message. Since we're creating new commits with the same commit + message, but possibly different content, from the original commits, this + can help to differentiate them and avoid confusion. + Whenever you split, you need to use the same <annotation>, or else you don't have a guarantee that the new re-created history will be identical to the old one. That will prevent merging from working correctly. git -subtree tries to make it work anyway, particularly if you use --rejoin, +subtree tries to make it work anyway, particularly if you use '--rejoin', but it may not always be effective. -b <branch>:: --branch=<branch>:: - This option is only valid for the split command. -+ -After generating the synthetic history, create a new branch called -<branch> that contains the new history. This is suitable for immediate -pushing upstream. <branch> must not already exist. + After generating the synthetic history, create a new branch called + <branch> that contains the new history. This is suitable for immediate + pushing upstream. <branch> must not already exist. --ignore-joins:: - This option is only valid for the split command. -+ -If you use '--rejoin', git subtree attempts to optimize its history -reconstruction to generate only the new commits since the last -'--rejoin'. '--ignore-join' disables this behaviour, forcing it to -regenerate the entire history. In a large project, this can take a long -time. + If you use '--rejoin', git subtree attempts to optimize its history + reconstruction to generate only the new commits since the last + '--rejoin'. '--ignore-joins' disables this behavior, forcing it to + regenerate the entire history. In a large project, this can take a long + time. --onto=<onto>:: - This option is only valid for the split command. -+ -If your subtree was originally imported using something other than git -subtree, its history may not match what git subtree is expecting. In -that case, you can specify the commit id <onto> that corresponds to the -first revision of the subproject's history that was imported into your -project, and git subtree will attempt to build its history from there. + If your subtree was originally imported using something other than git + subtree, its history may not match what git subtree is expecting. In + that case, you can specify the commit ID <onto> that corresponds to the + first revision of the subproject's history that was imported into your + project, and git subtree will attempt to build its history from there. + If you used 'git subtree add', you should never need this option. --rejoin:: - This option is only valid for the split command. -+ -After splitting, merge the newly created synthetic history back into -your main project. That way, future splits can search only the part of -history that has been added since the most recent --rejoin. + After splitting, merge the newly created synthetic history back into + your main project. That way, future splits can search only the part of + history that has been added since the most recent '--rejoin'. + If your split commits end up merged into the upstream subproject, and then you want to get the latest upstream version, this will allow git's @@ -235,13 +228,12 @@ Unfortunately, using this option results in 'git log' showing an extra copy of every new commit that was created (the original, and the synthetic one). + -If you do all your merges with '--squash', don't use '--rejoin' when you -split, because you don't want the subproject's history to be part of -your project anyway. +If you do all your merges with '--squash', make sure you also use +'--squash' when you 'split --rejoin'. -EXAMPLE 1. Add command ----------------------- +EXAMPLE 1. 'add' command +------------------------ Let's assume that you have a local repository that you would like to add an external vendor library to. In this case we will add the git-subtree repository as a subdirectory of your already existing @@ -253,15 +245,15 @@ git-extensions repository in ~/git-extensions/: 'master' needs to be a valid remote ref and can be a different branch name -You can omit the --squash flag, but doing so will increase the number +You can omit the '--squash' flag, but doing so will increase the number of commits that are included in your local repository. We now have a ~/git-extensions/git-subtree directory containing code from the master branch of git://github.com/apenwarr/git-subtree.git in our git-extensions repository. -EXAMPLE 2. Extract a subtree using commit, merge and pull ---------------------------------------------------------- +EXAMPLE 2. Extract a subtree using 'commit', 'merge' and 'pull' +--------------------------------------------------------------- Let's use the repository for the git source code as an example. First, get your own copy of the git.git repository: @@ -269,7 +261,7 @@ First, get your own copy of the git.git repository: $ cd test-git gitweb (commit 1130ef3) was merged into git as of commit -0a8f4f0, after which it was no longer maintained separately. +0a8f4f0, after which it was no longer maintained separately. But imagine it had been maintained separately, and we wanted to extract git's changes to gitweb since that time, to share with the upstream. You could do this: @@ -279,14 +271,14 @@ the upstream. You could do this: --branch gitweb-latest $ gitk gitweb-latest $ git push git@github.com:whatever/gitweb.git gitweb-latest:master - + (We use '0a8f4f0^..' because that means "all the changes from 0a8f4f0 to the current version, including 0a8f4f0 itself.") If gitweb had originally been merged using 'git subtree add' (or -a previous split had already been done with --rejoin specified) +a previous split had already been done with '--rejoin' specified) then you can do all your splits without having to remember any -weird commit ids: +weird commit IDs: $ git subtree split --prefix=gitweb --annotate='(split) ' --rejoin \ --branch gitweb-latest2 @@ -313,7 +305,7 @@ And fast forward again: $ git subtree merge --prefix=gitweb --squash gitweb-latest And notice that your change is still intact: - + $ ls -l gitweb/myfile And you can split it out and look at your changes versus @@ -321,8 +313,8 @@ the standard gitweb: git log gitweb-latest..$(git subtree split --prefix=gitweb) -EXAMPLE 3. Extract a subtree using branch ------------------------------------------ +EXAMPLE 3. Extract a subtree using a branch +------------------------------------------- Suppose you have a source directory with many files and subdirectories, and you want to extract the lib directory to its own git project. Here's a short way to do it: |