Autogenerated HTML docs for v1.4.4.2-gdb98
diff --git a/cvs-migration.txt b/cvs-migration.txt index a436180..47846bd 100644 --- a/cvs-migration.txt +++ b/cvs-migration.txt
@@ -1,33 +1,106 @@ git for CVS users ================= -So you're a CVS user. That's OK, it's a treatable condition. The job of -this document is to put you on the road to recovery, by helping you -convert an existing cvs repository to git, and by showing you how to use a -git repository in a cvs-like fashion. +Git differs from CVS in that every working tree contains a repository with +a full copy of the project history, and no repository is inherently more +important than any other. However, you can emulate the CVS model by +designating a single shared repository which people can synchronize with; +this document explains how to do that. Some basic familiarity with git is required. This link:tutorial.html[tutorial introduction to git] should be sufficient. -First, note some ways that git differs from CVS: +Developing against a shared repository +-------------------------------------- - * Commits are atomic and project-wide, not per-file as in CVS. +Suppose a shared repository is set up in /pub/repo.git on the host +foo.com. Then as an individual committer you can clone the shared +repository over ssh with: - * Offline work is supported: you can make multiple commits locally, - then submit them when you're ready. +------------------------------------------------ +$ git clone foo.com:/pub/repo.git/ my-project +$ cd my-project +------------------------------------------------ - * Branching is fast and easy. +and hack away. The equivalent of `cvs update` is - * Every working tree contains a repository with a full copy of the - project history, and no repository is inherently more important than - any other. However, you can emulate the CVS model by designating a - single shared repository which people can synchronize with; see below - for details. +------------------------------------------------ +$ git pull origin +------------------------------------------------ - * Since every working tree contains a repository, a commit in your - private repository will not publish your changes; it will only create - a revision. You have to "push" your changes to a public repository to - make them visible to others. +which merges in any work that others might have done since the clone +operation. If there are uncommitted changes in your working tree, commit +them first before running git pull. + +[NOTE] +================================ +The first `git clone` places the following in the +`my-project/.git/remotes/origin` file, and that's why the previous step +and the next step both work. +------------ +URL: foo.com:/pub/project.git/ +Pull: refs/heads/master:refs/remotes/origin/master +------------ +================================ + +You can update the shared repository with your changes by first commiting +your changes, and then using: + +------------------------------------------------ +$ git push origin master +------------------------------------------------ + +to "push" those commits to the shared repository. If someone else has +updated the repository more recently, `git push`, like `cvs commit`, will +complain, in which case you must pull any changes before attempting the +push again. + +In the `git push` command above we specify the name of the remote branch +to update (`master`). If we leave that out, `git push` tries to update +any branches in the remote repository that have the same name as a branch +in the local repository. So the last `push` can be done with either of: + +------------ +$ git push origin +$ git push foo.com:/pub/project.git/ +------------ + +as long as the shared repository does not have any branches +other than `master`. + +Setting Up a Shared Repository +------------------------------ + +We assume you have already created a git repository for your project, +possibly created from scratch or from a tarball (see the +link:tutorial.html[tutorial]), or imported from an already existing CVS +repository (see the next section). + +If your project's working directory is /home/alice/myproject, you can +create a shared repository at /pub/repo.git with: + +------------------------------------------------ +$ git clone -bare /home/alice/myproject /pub/repo.git +------------------------------------------------ + +Next, give every team member read/write access to this repository. One +easy way to do this is to give all the team members ssh access to the +machine where the repository is hosted. If you don't want to give them a +full shell on the machine, there is a restricted shell which only allows +users to do git pushes and pulls; see gitlink:git-shell[1]. + +Put all the committers in the same group, and make the repository +writable by that group: + +------------------------------------------------ +$ cd /pub +$ chgrp -R $group repo.git +$ find repo.git -mindepth 1 -type d |xargs chmod ug+rwx,g+s +$ GIT_DIR=repo.git git repo-config core.sharedrepository true +------------------------------------------------ + +Make sure committers have a umask of at most 027, so that the directories +they create are writable and searchable by other group members. Importing a CVS archive ----------------------- @@ -60,14 +133,32 @@ branches for your own changes, and merge in the imported branches as necessary. -Development Models ------------------- +Advanced Shared Repository Management +------------------------------------- + +Git allows you to specify scripts called "hooks" to be run at certain +points. You can use these, for example, to send all commits to the shared +repository to a mailing list. See link:hooks.html[Hooks used by git]. + +You can enforce finer grained permissions using update hooks. See +link:howto/update-hook-example.txt[Controlling access to branches using +update hooks]. + +Providing CVS Access to a git Repository +---------------------------------------- + +It is also possible to provide true CVS access to a git repository, so +that developers can still use CVS; see gitlink:git-cvsserver[1] for +details. + +Alternative Development Models +------------------------------ CVS users are accustomed to giving a group of developers commit access to -a common repository. In the next section we'll explain how to do this -with git. However, the distributed nature of git allows other development -models, and you may want to first consider whether one of them might be a -better fit for your project. +a common repository. As we've seen, this is also possible with git. +However, the distributed nature of git allows other development models, +and you may want to first consider whether one of them might be a better +fit for your project. For example, you can choose a single person to maintain the project's primary public repository. Other developers then clone this repository @@ -80,235 +171,3 @@ With a small group, developers may just pull changes from each other's repositories without the need for a central maintainer. - -Creating a Shared Repository ----------------------------- - -Start with an ordinary git working directory containing the project, and -remove the checked-out files, keeping just the bare .git directory: - ------------------------------------------------- -$ mv project/.git /pub/repo.git -$ rm -r project/ ------------------------------------------------- - -Next, give every team member read/write access to this repository. One -easy way to do this is to give all the team members ssh access to the -machine where the repository is hosted. If you don't want to give them a -full shell on the machine, there is a restricted shell which only allows -users to do git pushes and pulls; see gitlink:git-shell[1]. - -Put all the committers in the same group, and make the repository -writable by that group: - ------------------------------------------------- -$ chgrp -R $group repo.git -$ find repo.git -mindepth 1 -type d |xargs chmod ug+rwx,g+s -$ GIT_DIR=repo.git git repo-config core.sharedrepository true ------------------------------------------------- - -Make sure committers have a umask of at most 027, so that the directories -they create are writable and searchable by other group members. - -Performing Development on a Shared Repository ---------------------------------------------- - -Suppose a repository is now set up in /pub/repo.git on the host -foo.com. Then as an individual committer you can clone the shared -repository: - ------------------------------------------------- -$ git clone foo.com:/pub/repo.git/ my-project -$ cd my-project ------------------------------------------------- - -and hack away. The equivalent of `cvs update` is - ------------------------------------------------- -$ git pull origin ------------------------------------------------- - -which merges in any work that others might have done since the clone -operation. - -[NOTE] -================================ -The first `git clone` places the following in the -`my-project/.git/remotes/origin` file, and that's why the previous step -and the next step both work. ------------- -URL: foo.com:/pub/project.git/ my-project -Pull: master:origin ------------- -================================ - -You can update the shared repository with your changes by first commiting -your changes, and then using: - ------------------------------------------------- -$ git push origin master ------------------------------------------------- - -to "push" those commits to the shared repository. If someone else has -updated the repository more recently, `git push`, like `cvs commit`, will -complain, in which case you must pull any changes before attempting the -push again. - -In the `git push` command above we specify the name of the remote branch -to update (`master`). If we leave that out, `git push` tries to update -any branches in the remote repository that have the same name as a branch -in the local repository. So the last `push` can be done with either of: - ------------- -$ git push origin -$ git push repo.shared.xz:/pub/scm/project.git/ ------------- - -as long as the shared repository does not have any branches -other than `master`. - -[NOTE] -============ -Because of this behavior, if the shared repository and the developer's -repository both have branches named `origin`, then a push like the above -attempts to update the `origin` branch in the shared repository from the -developer's `origin` branch. The results may be unexpected, so it's -usually best to remove any branch named `origin` from the shared -repository. -============ - -Advanced Shared Repository Management -------------------------------------- - -Git allows you to specify scripts called "hooks" to be run at certain -points. You can use these, for example, to send all commits to the shared -repository to a mailing list. See link:hooks.html[Hooks used by git]. - -You can enforce finer grained permissions using update hooks. See -link:howto/update-hook-example.txt[Controlling access to branches using -update hooks]. - -CVS annotate ------------- - -So, something has gone wrong, and you don't know whom to blame, and -you're an ex-CVS user and used to do "cvs annotate" to see who caused -the breakage. You're looking for the "git annotate", and it's just -claiming not to find such a script. You're annoyed. - -Yes, that's right. Core git doesn't do "annotate", although it's -technically possible, and there are at least two specialized scripts out -there that can be used to get equivalent information (see the git -mailing list archives for details). - -git has a couple of alternatives, though, that you may find sufficient -or even superior depending on your use. One is called "git-whatchanged" -(for obvious reasons) and the other one is called "pickaxe" ("a tool for -the software archaeologist"). - -The "git-whatchanged" script is a truly trivial script that can give you -a good overview of what has changed in a file or a directory (or an -arbitrary list of files or directories). The "pickaxe" support is an -additional layer that can be used to further specify exactly what you're -looking for, if you already know the specific area that changed. - -Let's step back a bit and think about the reason why you would -want to do "cvs annotate a-file.c" to begin with. - -You would use "cvs annotate" on a file when you have trouble -with a function (or even a single "if" statement in a function) -that happens to be defined in the file, which does not do what -you want it to do. And you would want to find out why it was -written that way, because you are about to modify it to suit -your needs, and at the same time you do not want to break its -current callers. For that, you are trying to find out why the -original author did things that way in the original context. - -Many times, it may be enough to see the commit log messages of -commits that touch the file in question, possibly along with the -patches themselves, like this: - - $ git-whatchanged -p a-file.c - -This will show log messages and patches for each commit that -touches a-file. - -This, however, may not be very useful when this file has many -modifications that are not related to the piece of code you are -interested in. You would see many log messages and patches that -do not have anything to do with the piece of code you are -interested in. As an example, assuming that you have this piece -of code that you are interested in in the HEAD version: - - if (frotz) { - nitfol(); - } - -you would use git-rev-list and git-diff-tree like this: - - $ git-rev-list HEAD | - git-diff-tree --stdin -v -p -S'if (frotz) { - nitfol(); - }' - -We have already talked about the "\--stdin" form of git-diff-tree -command that reads the list of commits and compares each commit -with its parents (otherwise you should go back and read the tutorial). -The git-whatchanged command internally runs -the equivalent of the above command, and can be used like this: - - $ git-whatchanged -p -S'if (frotz) { - nitfol(); - }' - -When the -S option is used, git-diff-tree command outputs -differences between two commits only if one tree has the -specified string in a file and the corresponding file in the -other tree does not. The above example looks for a commit that -has the "if" statement in it in a file, but its parent commit -does not have it in the same shape in the corresponding file (or -the other way around, where the parent has it and the commit -does not), and the differences between them are shown, along -with the commit message (thanks to the -v flag). It does not -show anything for commits that do not touch this "if" statement. - -Also, in the original context, the same statement might have -appeared at first in a different file and later the file was -renamed to "a-file.c". CVS annotate would not help you to go -back across such a rename, but git would still help you in such -a situation. For that, you can give the -C flag to -git-diff-tree, like this: - - $ git-whatchanged -p -C -S'if (frotz) { - nitfol(); - }' - -When the -C flag is used, file renames and copies are followed. -So if the "if" statement in question happens to be in "a-file.c" -in the current HEAD commit, even if the file was originally -called "o-file.c" and then renamed in an earlier commit, or if -the file was created by copying an existing "o-file.c" in an -earlier commit, you will not lose track. If the "if" statement -did not change across such a rename or copy, then the commit that -does rename or copy would not show in the output, and if the -"if" statement was modified while the file was still called -"o-file.c", it would find the commit that changed the statement -when it was in "o-file.c". - -NOTE: The current version of "git-diff-tree -C" is not eager - enough to find copies, and it will miss the fact that a-file.c - was created by copying o-file.c unless o-file.c was somehow - changed in the same commit. - -You can use the --pickaxe-all flag in addition to the -S flag. -This causes the differences from all the files contained in -those two commits, not just the differences between the files -that contain this changed "if" statement: - - $ git-whatchanged -p -C -S'if (frotz) { - nitfol(); - }' --pickaxe-all - -NOTE: This option is called "--pickaxe-all" because -S - option is internally called "pickaxe", a tool for software - archaeologists. 