git-p4: add p4 submit hooks

The git command "commit" supports a number of hooks that support
changing the behavior of the commit command.  The git-p4.py program only
has one existing hook, "p4-pre-submit".  This command occurs early in
the process.  There are no hooks in the process flow for modifying
the P4 changelist text programmatically.

Adds 3 new hooks to git-p4.py to the submit option.

The new hooks are:
* p4-prepare-changelist - Execute this hook after the changelist file
  has been created. The hook will be executed even if the
  --prepare-p4-only option is set.  This hook ignores the --no-verify
  option in keeping with the existing behavior of git commit.

* p4-changelist - Execute this hook after the user has edited the
  changelist. Do not execute this hook if the user has selected the
  --prepare-p4-only option. This hook will honor the --no-verify,
  following the conventions of git commit.

* p4-post-changelist - Execute this hook after the P4 submission process
  has completed successfully. This hook takes no parameters and is
  executed regardless of the --no-verify option.  It's return value will
  not be checked.

The calls to the new hooks: p4-prepare-changelist, p4-changelist,
and p4-post-changelist should all be called inside the try-finally
block.

Signed-off-by: Ben Keene <seraphire@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/Documentation/git-p4.txt b/Documentation/git-p4.txt
index 362b50eb21..dab9609013 100644
--- a/Documentation/git-p4.txt
+++ b/Documentation/git-p4.txt
@@ -387,6 +387,41 @@ It can be bypassed with the `--no-verify` command line option.
 
 One usage scenario is to run unit tests in the hook.
 
+p4-prepare-changelist
+~~~~~~~~~~~~~~~~~~~~~
+
+The `p4-prepare-changelist` hook is executed right after preparing
+the default changelist message and before the editor is started.
+It takes one parameter, the name of the file that contains the
+changelist text. Exiting with a non-zero status from the script
+will abort the process.
+
+The purpose of the hook is to edit the message file in place,
+and it is not supressed by the `--no-verify` option. This hook
+is called even if `--prepare-p4-only` is set.
+
+p4-changelist
+~~~~~~~~~~~~~
+
+The `p4-changelist` hook is executed after the changelist
+message has been edited by the user. It can be bypassed with the
+`--no-verify` option. It takes a single parameter, the name
+of the file that holds the proposed changelist text. Exiting
+with a non-zero status causes the command to abort.
+
+The hook is allowed to edit the changelist file and can be used
+to normalize the text into some project standard format. It can
+also be used to refuse the Submit after inspect the message file.
+
+p4-post-changelist
+~~~~~~~~~~~~~~~~~~
+
+The `p4-post-changelist` hook is invoked after the submit has
+successfully occured in P4. It takes no parameters and is meant
+primarily for notification and cannot affect the outcome of the
+git p4 submit action.
+
+
 
 Rebase options
 ~~~~~~~~~~~~~~