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