git-p4: introduce asciidoc documentation

Add proper documentation for git-p4.  Delete the old .txt
documentation from contrib/fast-import.

Cc: Frans Klaver <fransklaver@gmail.com>
Cc: Luke Diamand <luke@diamand.org>
Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 455 insertions, 0 deletions

diff --git a/Documentation/git-p4.txt b/Documentation/git-p4.txt
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+git-p4(1)
+=========
+
+NAME
+----
+git-p4 - Import from and submit to Perforce repositories
+
+
+SYNOPSIS
+--------
+[verse]
+'git p4 clone' [<sync options>] [<clone options>] <p4 depot path>...
+'git p4 sync' [<sync options>] [<p4 depot path>...]
+'git p4 rebase'
+'git p4 submit' [<submit options>] [<master branch name>]
+
+
+DESCRIPTION
+-----------
+This command provides a way to interact with p4 repositories
+using git.
+
+Create a new git repository from an existing p4 repository using
+'git p4 clone', giving it one or more p4 depot paths.  Incorporate
+new commits from p4 changes with 'git p4 sync'.  The 'sync' command
+is also used to include new branches from other p4 depot paths.
+Submit git changes back to p4 using 'git p4 submit'.  The command
+'git p4 rebase' does a sync plus rebases the current branch onto
+the updated p4 remote branch.
+
+
+EXAMPLE
+-------
+* Create an alias for 'git p4', using the full path to the 'git-p4'
+  script if needed:
++
+------------
+$ git config --global alias.p4 '!git-p4'
+------------
+
+* Clone a repository:
++
+------------
+$ git p4 clone //depot/path/project
+------------
+
+* Do some work in the newly created git repository:
++
+------------
+$ cd project
+$ vi foo.h
+$ git commit -a -m "edited foo.h"
+------------
+
+* Update the git repository with recent changes from p4, rebasing your
+  work on top:
++
+------------
+$ git p4 rebase
+------------
+
+* Submit your commits back to p4:
++
+------------
+$ git p4 submit
+------------
+
+
+COMMANDS
+--------
+
+Clone
+~~~~~
+Generally, 'git p4 clone' is used to create a new git directory
+from an existing p4 repository:
+------------
+$ git p4 clone //depot/path/project
+------------
+This:
+
+1.   Creates an empty git repository in a subdirectory called 'project'.
++
+2.   Imports the full contents of the head revision from the given p4
+depot path into a single commit in the git branch 'refs/remotes/p4/master'.
++
+3.   Creates a local branch, 'master' from this remote and checks it out.
+
+To reproduce the entire p4 history in git, use the '@all' modifier on
+the depot path:
+------------
+$ git p4 clone //depot/path/project@all
+------------
+
+
+Sync
+~~~~
+As development continues in the p4 repository, those changes can
+be included in the git repository using:
+------------
+$ git p4 sync
+------------
+This command finds new changes in p4 and imports them as git commits.
+
+P4 repositories can be added to an existing git repository using
+'git p4 sync' too:
+------------
+$ mkdir repo-git
+$ cd repo-git
+$ git init
+$ git p4 sync //path/in/your/perforce/depot
+------------
+This imports the specified depot into
+'refs/remotes/p4/master' in an existing git repository.  The
+'--branch' option can be used to specify a different branch to
+be used for the p4 content.
+
+If a git repository includes branches 'refs/remotes/origin/p4', these
+will be fetched and consulted first during a 'git p4 sync'.  Since
+importing directly from p4 is considerably slower than pulling changes
+from a git remote, this can be useful in a multi-developer environment.
+
+
+Rebase
+~~~~~~
+A common working pattern is to fetch the latest changes from the p4 depot
+and merge them with local uncommitted changes.  Often, the p4 repository
+is the ultimate location for all code, thus a rebase workflow makes
+sense.  This command does 'git p4 sync' followed by 'git rebase' to move
+local commits on top of updated p4 changes.
+------------
+$ git p4 rebase
+------------
+
+
+Submit
+~~~~~~
+Submitting changes from a git repository back to the p4 repository
+requires a separate p4 client workspace.  This should be specified
+using the 'P4CLIENT' environment variable or the git configuration
+variable 'git-p4.client'.  The p4 client must exist, but the client root
+will be created and populated if it does not already exist.
+
+To submit all changes that are in the current git branch but not in
+the 'p4/master' branch, use:
+------------
+$ git p4 submit
+------------
+
+To specify a branch other than the current one, use:
+------------
+$ git p4 submit topicbranch
+------------
+
+The upstream reference is generally 'refs/remotes/p4/master', but can
+be overridden using the '--origin=' command-line option.
+
+The p4 changes will be created as the user invoking 'git p4 submit'. The
+'--preserve-user' option will cause ownership to be modified
+according to the author of the git commit.  This option requires admin
+privileges in p4, which can be granted using 'p4 protect'.
+
+
+OPTIONS
+-------
+
+General options
+~~~~~~~~~~~~~~~
+All commands except clone accept this option.
+
+--git-dir <dir>::
+	Set the 'GIT_DIR' environment variable.  See linkgit:git[1].
+
+Sync options
+~~~~~~~~~~~~
+These options can be used in the initial 'clone' as well as in
+subsequent 'sync' operations.
+
+--branch <branch>::
+	Import changes into given branch.  If the branch starts with
+	'refs/', it will be used as is, otherwise the path 'refs/heads/'
+	will be prepended.  The default branch is 'master'.
+
+--detect-branches::
+	Use the branch detection algorithm to find new paths in p4.  It is
+	documented below in "BRANCH DETECTION".
+
+--changesfile <file>::
+	Import exactly the p4 change numbers listed in 'file', one per
+	line.  Normally, 'git p4' inspects the current p4 repository
+	state and detects the changes it should import.
+
+--silent::
+	Do not print any progress information.
+
+--verbose::
+	Provide more progress information.
+
+--detect-labels::
+	Query p4 for labels associated with the depot paths, and add
+	them as tags in git.
+
+--import-local::
+	By default, p4 branches are stored in 'refs/remotes/p4/',
+	where they will be treated as remote-tracking branches by
+	linkgit:git-branch[1] and other commands.  This option instead
+	puts p4 branches in 'refs/heads/p4/'.
+
+--max-changes <n>::
+	Limit the number of imported changes to 'n'.  Useful to
+	limit the amount of history when using the '@all' p4 revision
+	specifier.
+
+--keep-path::
+	The mapping of file names from the p4 depot path to git, by
+	default, involves removing the entire depot path.  With this
+	option, the full p4 depot path is retained in git.  For example,
+	path '//depot/main/foo/bar.c', when imported from
+	'//depot/main/', becomes 'foo/bar.c'.  With '--keep-path', the
+	git path is instead 'depot/main/foo/bar.c'.
+
+--use-client-spec::
+	Use a client spec to find the list of interesting files in p4.
+	The client spec is discovered using 'p4 client -o' which checks
+	the 'P4CLIENT' environment variable and returns a mapping of
+	depot files to workspace files.
+
+Clone options
+~~~~~~~~~~~~~
+These options can be used in an initial 'clone', along with the 'sync'
+options described above.
+
+--destination <directory>::
+	Where to create the git repository.  If not provided, the last
+	component in the p4 depot path is used to create a new
+	directory.
+
+--bare::
+	Perform a bare clone.  See linkgit:git-clone[1].
+
+-/ <path>::
+	Exclude selected depot paths when cloning.
+
+Submit options
+~~~~~~~~~~~~~~
+These options can be used to modify 'git p4 submit' behavior.
+
+--verbose::
+	Provide more progress information.
+
+--origin <commit>::
+	Upstream location from which commits are identified to submit to
+	p4.  By default, this is the most recent p4 commit reachable
+	from 'HEAD'.
+
+-M[<n>]::
+	Detect renames.  See linkgit:git-diff[1].  Renames will be
+	represented in p4 using explicit 'move' operations.
+
+--preserve-user::
+	Re-author p4 changes before submitting to p4.  This option
+	requires p4 admin privileges.
+
+
+DEPOT PATH SYNTAX
+-----------------
+The p4 depot path argument to 'git p4 sync' and 'git p4 clone' can
+be one or more space-separated p4 depot paths, with an optional
+p4 revision specifier on the end:
+
+"//depot/my/project"::
+    Import one commit with all files in the '#head' change under that tree.
+
+"//depot/my/project@all"::
+    Import one commit for each change in the history of that depot path.
+
+"//depot/my/project@1,6"::
+    Import only changes 1 through 6.
+
+"//depot/proj1 //depot/proj2@all"::
+    Import all changes from both named depot paths.
+
+See 'p4 help revisions' for the full syntax of p4 revision specifiers.
+
+
+BRANCH DETECTION
+----------------
+P4 does not have the same concept of a branch as git.  Instead,
+p4 organizes its content as a directory tree, where by convention
+different logical branches are in different locations in the tree.
+The 'p4 branch' command is used to maintain mappings between
+different areas in the tree, and indicate related content.  'git p4'
+can use these mappings to determine branch relationships.
+
+If you have a repository where all the branches of interest exist as
+subdirectories of a single depot path, you can use '--detect-branches'
+when cloning or syncing to have 'git p4' automatically find
+subdirectories in p4, and to generate these as branches in git.
+
+For example, if the P4 repository structure is:
+----
+//depot/main/...
+//depot/branch1/...
+----
+
+And "p4 branch -o branch1" shows a View line that looks like:
+----
+//depot/main/... //depot/branch1/...
+----
+
+Then this 'git p4 clone' command:
+----
+git p4 clone --detect-branches //depot@all
+----
+produces a separate branch in 'refs/remotes/p4/' for //depot/main,
+called 'master', and one for //depot/branch1 called 'depot/branch1'.
+
+However, it is not necessary to create branches in p4 to be able to use
+them like branches.  Because it is difficult to infer branch
+relationships automatically, a git configuration setting
+'git-p4.branchList' can be used to explicitly identify branch
+relationships.  It is a list of "source:destination" pairs, like a
+simple p4 branch specification, where the "source" and "destination" are
+the path elements in the p4 repository.  The example above relied on the
+presence of the p4 branch.  Without p4 branches, the same result will
+occur with:
+----
+git config git-p4.branchList main:branch1
+git p4 clone --detect-branches //depot@all
+----
+
+
+PERFORMANCE
+-----------
+The fast-import mechanism used by 'git p4' creates one pack file for
+each invocation of 'git p4 sync'.  Normally, git garbage compression
+(linkgit:git-gc[1]) automatically compresses these to fewer pack files,
+but explicit invocation of 'git repack -adf' may improve performance.
+
+
+CONFIGURATION VARIABLES
+-----------------------
+The following config settings can be used to modify 'git p4' behavior.
+They all are in the 'git-p4' section.
+
+General variables
+~~~~~~~~~~~~~~~~~
+git-p4.user::
+	User specified as an option to all p4 commands, with '-u <user>'.
+	The environment variable 'P4USER' can be used instead.
+
+git-p4.password::
+	Password specified as an option to all p4 commands, with
+	'-P <password>'.
+	The environment variable 'P4PASS' can be used instead.
+
+git-p4.port::
+	Port specified as an option to all p4 commands, with
+	'-p <port>'.
+	The environment variable 'P4PORT' can be used instead.
+
+git-p4.host::
+	Host specified as an option to all p4 commands, with
+	'-h <host>'.
+	The environment variable 'P4HOST' can be used instead.
+
+git-p4.client::
+	Client specified as an option to all p4 commands, with
+	'-c <client>'.  This can also be used as a way to find
+	the client spec for the 'useClientSpec' option.
+	The environment variable 'P4CLIENT' can be used instead.
+
+Clone and sync variables
+~~~~~~~~~~~~~~~~~~~~~~~~
+git-p4.syncFromOrigin::
+	Because importing commits from other git repositories is much faster
+	than importing them from p4, a mechanism exists to find p4 changes
+	first in git remotes.  If branches exist under 'refs/remote/origin/p4',
+	those will be fetched and used when syncing from p4.  This
+	variable can be set to 'false' to disable this behavior.
+
+git-p4.branchUser::
+	One phase in branch detection involves looking at p4 branches
+	to find new ones to import.  By default, all branches are
+	inspected.  This option limits the search to just those owned
+	by the single user named in the variable.
+
+git-p4.branchList::
+	List of branches to be imported when branch detection is
+	enabled.  Each entry should be a pair of branch names separated
+	by a colon (:).  This example declares that both branchA and
+	branchB were created from main:
+-------------
+git config       git-p4.branchList main:branchA
+git config --add git-p4.branchList main:branchB
+-------------
+
+git-p4.useClientSpec::
+	Specify that the p4 client spec to be used to identify p4 depot
+	paths of interest.  This is equivalent to specifying the option
+	'--use-client-spec'.  The variable 'git-p4.client' can be used
+	to specify the name of the client.
+
+Submit variables
+~~~~~~~~~~~~~~~~
+git-p4.detectRenames::
+	Detect renames.  See linkgit:git-diff[1].
+
+git-p4.detectCopies::
+	Detect copies.  See linkgit:git-diff[1].
+
+git-p4.detectCopiesHarder::
+	Detect copies harder.  See linkgit:git-diff[1].
+
+git-p4.preserveUser::
+	On submit, re-author changes to reflect the git author,
+	regardless of who invokes 'git p4 submit'.
+
+git-p4.allowMissingP4Users::
+	When 'preserveUser' is true, 'git p4' normally dies if it
+	cannot find an author in the p4 user map.  This setting
+	submits the change regardless.
+
+git-p4.skipSubmitEdit::
+	The submit process invokes the editor before each p4 change
+	is submitted.  If this setting is true, though, the editing
+	step is skipped.
+
+git-p4.skipSubmitEditCheck::
+	After editing the p4 change message, 'git p4' makes sure that
+	the description really was changed by looking at the file
+	modification time.  This option disables that test.
+
+git-p4.allowSubmit::
+	By default, any branch can be used as the source for a 'git p4
+	submit' operation.  This configuration variable, if set, permits only
+	the named branches to be used as submit sources.
+
+git-p4.skipUserNameCheck::
+	If the user running 'git p4 submit' does not exist in the p4
+	user map, 'git p4' exits.  This option can be used to force
+	submission regardless.
+
+
+IMPLEMENTATION DETAILS
+----------------------
+* Changesets from p4 are imported using git fast-import.
+* Cloning or syncing does not require a p4 client; file contents are
+  collected using 'p4 print'.
+* Submitting requires a p4 client, which is not in the same location
+  as the git repository.  Patches are applied, one at a time, to
+  this p4 client and submitted from there.
+* Each commit imported by 'git p4' has a line at the end of the log
+  message indicating the p4 depot location and change number.  This
+  line is used by later 'git p4 sync' operations to know which p4
+  changes are new.