merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 43 insertions, 2 deletions

diff --git a/third_party/git/Documentation/git-p4.txt b/third_party/git/Documentation/git-p4.txt
index 3494a1db3ebf..dab9609013fd 100644
--- a/third_party/git/Documentation/git-p4.txt
+++ b/third_party/git/Documentation/git-p4.txt
@@ -374,14 +374,55 @@ These options can be used to modify 'git p4 submit' behavior.
     been submitted. Implies --disable-rebase. Can also be set with
     git-p4.disableP4Sync. Sync with origin/master still goes ahead if possible.
 
-Hook for submit
-~~~~~~~~~~~~~~~
+Hooks for submit
+----------------
+
+p4-pre-submit
+~~~~~~~~~~~~~
+
 The `p4-pre-submit` hook is executed if it exists and is executable.
 The hook takes no parameters and nothing from standard input. Exiting with
 non-zero status from this script prevents `git-p4 submit` from launching.
+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
 ~~~~~~~~~~~~~~
 These options can be used to modify 'git p4 rebase' behavior.