contrib/fast-import/git-p4.txt

   1 git-p4 - Perforce <-> Git converter using git-fast-import
   2
   3 Usage
   4 =====
   5
   6 git-p4 can be used in two different ways:
   7
   8 1) To import changes from Perforce to a Git repository, using "git-p4 sync".
   9
  10 2) To submit changes from Git back to Perforce, using "git-p4 submit".
  11
  12 Importing
  13 =========
  14
  15 Simply start with
  16
  17   git-p4 clone //depot/path/project
  18
  19 or
  20
  21   git-p4 clone //depot/path/project myproject
  22
  23 This will:
  24
  25 1) Create an empty git repository in a subdirectory called "project" (or
  26 "myproject" with the second command)
  27
  28 2) Import the head revision from the given Perforce path into a git branch
  29 called "p4" (remotes/p4 actually)
  30
  31 3) Create a master branch based on it and check it out.
  32
  33 If you want the entire history (not just the head revision) then you can simply
  34 append a "@all" to the depot path:
  35
  36   git-p4 clone //depot/project/main@all myproject
  37
  38
  39
  40 If you want more control you can also use the git-p4 sync command directly:
  41
  42   mkdir repo-git
  43   cd repo-git
  44   git init
  45   git-p4 sync //path/in/your/perforce/depot
  46
  47 This will import the current head revision of the specified depot path into a
  48 "remotes/p4/master" branch of your git repository. You can use the
  49 --branch=mybranch option to import into a different branch.
  50
  51 If you want to import the entire history of a given depot path simply use:
  52
  53   git-p4 sync //path/in/depot@all
  54
  55
  56 Note:
  57
  58 To achieve optimal compression you may want to run 'git repack -a -d -f' after
  59 a big import. This may take a while.
  60
  61 Incremental Imports
  62 ===================
  63
  64 After an initial import you can continue to synchronize your git repository
  65 with newer changes from the Perforce depot by just calling
  66
  67   git-p4 sync
  68
  69 in your git repository. By default the "remotes/p4/master" branch is updated.
  70
  71 Advanced Setup
  72 ==============
  73
  74 Suppose you have a periodically updated git repository somewhere, containing a
  75 complete import of a Perforce project. This repository can be cloned and used
  76 with git-p4. When updating the cloned repository with the "sync" command,
  77 git-p4 will try to fetch changes from the original repository first. The git
  78 protocol used with this is usually faster than importing from Perforce
  79 directly.
  80
  81 This behaviour can be disabled by setting the "git-p4.syncFromOrigin" git
  82 configuration variable to "false".
  83
  84 Updating
  85 ========
  86
  87 A common working pattern is to fetch the latest changes from the Perforce depot
  88 and merge them with local uncommitted changes. The recommended way is to use
  89 git's rebase mechanism to preserve linear history. git-p4 provides a convenient
  90
  91   git-p4 rebase
  92
  93 command that calls git-p4 sync followed by git rebase to rebase the current
  94 working branch.
  95
  96 Submitting
  97 ==========
  98
  99 git-p4 has support for submitting changes from a git repository back to the
 100 Perforce depot. This requires a Perforce checkout separate from your git
 101 repository. To submit all changes that are in the current git branch but not in
 102 the "p4" branch (or "origin" if "p4" doesn't exist) simply call
 103
 104     git-p4 submit
 105
 106 in your git repository. If you want to submit changes in a specific branch that
 107 is not your current git branch you can also pass that as an argument:
 108
 109     git-p4 submit mytopicbranch
 110
 111 You can override the reference branch with the --origin=mysourcebranch option.
 112
 113 The Perforce changelists will be created with the user who ran git-p4. If you
 114 use --preserve-user then git-p4 will attempt to create Perforce changelists
 115 with the Perforce user corresponding to the git commit author. You need to
 116 have sufficient permissions within Perforce, and the git users need to have
 117 Perforce accounts. Permissions can be granted using 'p4 protect'.
 118
 119 If a submit fails you may have to "p4 resolve" and submit manually. You can
 120 continue importing the remaining changes with
 121
 122   git-p4 submit --continue
 123
 124 Example
 125 =======
 126
 127 # Clone a repository
 128   git-p4 clone //depot/path/project
 129 # Enter the newly cloned directory
 130   cd project
 131 # Do some work...
 132   vi foo.h
 133 # ... and commit locally to gi
 134   git commit foo.h
 135 # In the meantime somebody submitted changes to the Perforce depot. Rebase your latest
 136 # changes against the latest changes in Perforce:
 137   git-p4 rebase
 138 # Submit your locally committed changes back to Perforce
 139   git-p4 submit
 140 # ... and synchronize with Perforce
 141   git-p4 rebase
 142
 143
 144 Configuration parameters
 145 ========================
 146
 147 git-p4.user ($P4USER)
 148
 149 Allows you to specify the username to use to connect to the Perforce repository.
 150
 151   git config [--global] git-p4.user public
 152
 153 git-p4.password ($P4PASS)
 154
 155 Allows you to specify the password to use to connect to the Perforce repository.
 156 Warning this password will be visible on the command-line invocation of the p4 binary.
 157
 158   git config [--global] git-p4.password public1234
 159
 160 git-p4.port ($P4PORT)
 161
 162 Specify the port to be used to contact the Perforce server. As this will be passed
 163 directly to the p4 binary, it may be in the format host:port as well.
 164
 165   git config [--global] git-p4.port codes.zimbra.com:2666
 166
 167 git-p4.host ($P4HOST)
 168
 169 Specify the host to contact for a Perforce repository.
 170
 171   git config [--global] git-p4.host perforce.example.com
 172
 173 git-p4.client ($P4CLIENT)
 174
 175 Specify the client name to use
 176
 177   git config [--global] git-p4.client public-view
 178
 179 git-p4.allowSubmit
 180
 181   git config [--global] git-p4.allowSubmit false
 182
 183 git-p4.syncFromOrigin
 184
 185 A useful setup may be that you have a periodically updated git repository
 186 somewhere that contains a complete import of a Perforce project. That git
 187 repository can be used to clone the working repository from and one would
 188 import from Perforce directly after cloning using git-p4. If the connection to
 189 the Perforce server is slow and the working repository hasn't been synced for a
 190 while it may be desirable to fetch changes from the origin git repository using
 191 the efficient git protocol. git-p4 supports this setup by calling "git fetch origin"
 192 by default if there is an origin branch. You can disable this using:
 193
 194   git config [--global] git-p4.syncFromOrigin false
 195
 196 git-p4.useclientspec
 197
 198   git config [--global] git-p4.useclientspec false
 199
 200 The P4CLIENT environment variable should be correctly set for p4 to be
 201 able to find the relevant client.  This client spec will be used to
 202 both filter the files cloned by git and set the directory layout as
 203 specified in the client (this implies --keep-path style semantics).
 204
 205 git-p4.skipSubmitModTimeCheck
 206
 207   git config [--global] git-p4.skipSubmitModTimeCheck false
 208
 209 If true, submit will not check if the p4 change template has been modified.
 210
 211 git-p4.preserveUser
 212
 213   git config [--global] git-p4.preserveUser false
 214
 215 If true, attempt to preserve user names by modifying the p4 changelists. See
 216 the "--preserve-user" submit option.
 217
 218 git-p4.allowMissingPerforceUsers
 219
 220   git config [--global] git-p4.allowMissingP4Users false
 221
 222 If git-p4 is setting the perforce user for a commit (--preserve-user) then
 223 if there is no perforce user corresponding to the git author, git-p4 will
 224 stop. With allowMissingPerforceUsers set to true, git-p4 will use the
 225 current user (i.e. the behavior without --preserve-user) and carry on with
 226 the perforce commit.
 227
 228 git-p4.skipUserNameCheck
 229
 230   git config [--global] git-p4.skipUserNameCheck false
 231
 232 When submitting, git-p4 checks that the git commits are authored by the current
 233 p4 user, and warns if they are not. This disables the check.
 234
 235 git-p4.detectRenames
 236
 237 Detect renames when submitting changes to Perforce server. Will enable -M git
 238 argument. Can be optionally set to a number representing the threshold
 239 percentage value of the rename detection.
 240
 241   git config [--global] git-p4.detectRenames true
 242   git config [--global] git-p4.detectRenames 50
 243
 244 git-p4.detectCopies
 245
 246 Detect copies when submitting changes to Perforce server. Will enable -C git
 247 argument. Can be optionally set to a number representing the threshold
 248 percentage value of the copy detection.
 249
 250   git config [--global] git-p4.detectCopies true
 251   git config [--global] git-p4.detectCopies 80
 252
 253 git-p4.detectCopiesHarder
 254
 255 Detect copies even between files that did not change when submitting changes to
 256 Perforce server. Will enable --find-copies-harder git argument.
 257
 258   git config [--global] git-p4.detectCopies true
 259
 260 git-p4.branchUser
 261
 262 Only use branch specifications defined by the selected username.
 263
 264   git config [--global] git-p4.branchUser username
 265
 266 git-p4.branchList
 267
 268 List of branches to be imported when branch detection is enabled.
 269
 270   git config [--global] git-p4.branchList main:branchA
 271   git config [--global] --add git-p4.branchList main:branchB
 272
 273 Implementation Details...
 274 =========================
 275
 276 * Changesets from Perforce are imported using git fast-import.
 277 * The import does not require anything from the Perforce client view as it just uses
 278   "p4 print //depot/path/file#revision" to get the actual file contents.
 279 * Every imported changeset has a special [git-p4...] line at the
 280   end of the log message that gives information about the corresponding
 281   Perforce change number and is also used by git-p4 itself to find out
 282   where to continue importing when doing incremental imports.
 283   Basically when syncing it extracts the perforce change number of the
 284   latest commit in the "p4" branch and uses "p4 changes //depot/path/...@changenum,#head"
 285   to find out which changes need to be imported.
 286 * git-p4 submit uses "git rev-list" to pick the commits between the "p4" branch
 287   and the current branch.
 288   The commits themselves are applied using git diff/format-patch ... | git apply
 289