git-p4 - Perforce <-> Git converter using git-fast-import Usage ===== git-p4 supports two main modes: Importing from Perforce to a Git repository is done using "git-p4 sync" or "git-p4 rebase". Submitting changes from Git back to Perforce is done using "git-p4 submit". Importing ========= You can simply start with git-p4 clone //depot/path/project or git-p4 clone //depot/path/project myproject This will create an empty git repository in a subdirectory called "project" (or "myproject" with the second command), import the head revision from the specified perforce path into a git "p4" branch (remotes/p4 actually), create a master branch off it and check it out. If you want the entire history (not just the head revision) then you can simply append a "@all" to the depot path: git-p4 clone //depot/project/main@all myproject If you want more control you can also use the git-p4 sync command directly: mkdir repo-git cd repo-git git init git-p4 sync //path/in/your/perforce/depot This will import the current head revision of the specified depot path into a "remotes/p4/master" branch of your git repository. You can use the --branch=mybranch option to use a different branch. If you want to import the entire history of a given depot path just use git-p4 sync //path/in/depot@all To achieve optimal compression you may want to run 'git repack -a -d -f' after a big import. This may take a while. Support for Perforce integrations is still work in progress. Don't bother trying it unless you want to hack on it :) Incremental Imports =================== After an initial import you can easily synchronize your git repository with newer changes from the Perforce depot by just calling git-p4 sync in your git repository. By default the "remotes/p4/master" branch is updated. It is recommended to run 'git repack -a -d -f' from time to time when using incremental imports to optimally combine the individual git packs that each incremental import creates through the use of git-fast-import. Updating ======== A common working pattern is to fetch the latest changes from the Perforce depot and merge them with local uncommitted changes. The recommended way is to use git's rebase mechanism to preserve linear history. git-p4 provides a convenient git-p4 rebase command that calls git-p4 sync followed by git rebase to rebase the current working branch. Submitting ========== git-p4 has support for submitting changes from a git repository back to the Perforce depot. This requires a Perforce checkout separate to your git repository. To submit all changes that are in the current git branch but not in the "p4" branch (or "origin" if "p4" doesn't exist) simply call git-p4 submit in your git repository. If you want to submit changes in a specific branch that is not your current git branch you can also pass that as an argument: git-p4 submit mytopicbranch You can override the reference branch with the --origin=mysourcebranch option. If a submit fails you may have to "p4 resolve" and submit manually. You can continue importing the remaining changes with git-p4 submit --continue After submitting you should sync your perforce import branch ("p4" or "origin") from Perforce using git-p4's sync command. If you have changes in your working directory that you haven't committed into git yet but that you want to commit to Perforce directly ("quick fixes") then you do not have to go through the intermediate step of creating a git commit first but you can just call git-p4 submit --direct Example ======= # Clone a repository git-p4 clone //depot/path/project # Enter the newly cloned directory cd project # Do some work... vi foo.h # ... and commit locally to gi git commit foo.h # In the meantime somebody submitted changes to the Perforce depot. Rebase your latest # changes against the latest changes in Perforce: git-p4 rebase # Submit your locally committed changes back to Perforce git-p4 submit # ... and synchronize with Perforce git-p4 rebase Configuration parameters ======================== git-p4.user ($P4USER) Allows you to specify the username to use to connect to the Perforce repository. git config [--global] git-p4.user public git-p4.password ($P4PASS) Allows you to specify the password to use to connect to the Perforce repository. Warning this password will be visible on the command-line invocation of the p4 binary. git config [--global] git-p4.password public1234 git-p4.port ($P4PORT) Specify the port to be used to contact the Perforce server. As this will be passed directly to the p4 binary, it may be in the format host:port as well. git config [--global] git-p4.port codes.zimbra.com:2666 git-p4.host ($P4HOST) Specify the host to contact for a Perforce repository. git config [--global] git-p4.host perforce.example.com git-p4.client ($P4CLIENT) Specify the client name to use git config [--global] git-p4.client public-view git-p4.syncFromOrigin A useful setup may be that you have a periodically updated git repository somewhere that contains a complete import of a Perforce project. That git repository can be used to clone the working repository from and one would import from Perforce directly after cloning using git-p4. If the connection to the Perforce server is slow and the working repository hasn't been synced for a while it may be desirable to fetch changes from the origin git repository using the efficient git protocol. git-p4 supports this setup by calling "git fetch origin" by default if there is an origin branch. You can disable this using: git config [--global] git-p4.syncFromOrigin false Implementation Details... ========================= * Changesets from Perforce are imported using git fast-import. * The import does not require anything from the Perforce client view as it just uses "p4 print //depot/path/file#revision" to get the actual file contents. * Every imported changeset has a special [git-p4...] line at the end of the log message that gives information about the corresponding Perforce change number and is also used by git-p4 itself to find out where to continue importing when doing incremental imports. Basically when syncing it extracts the perforce change number of the latest commit in the "p4" branch and uses "p4 changes //depot/path/...@changenum,#head" to find out which changes need to be imported. * git-p4 submit uses "git rev-list" to pick the commits between the "p4" branch and the current branch. The commits themselves are applied using git diff/format-patch ... | git apply