git-p4: add the `p4-pre-submit` hook

The `p4-pre-submit` hook is executed before git-p4 submits code.
If the hook exits with non-zero value, submit process not start.

Signed-off-by: Chen Bin <chenbin.sh@gmail.com>
Reviewed-by: Luke Diamand <luke@diamand.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/git-p4.py b/git-p4.py
index b449db1cc9..7fab255584 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -1494,7 +1494,13 @@ class P4Submit(Command, P4UserMap):
                 optparse.make_option("--disable-p4sync", dest="disable_p4sync", action="store_true",
                                      help="Skip Perforce sync of p4/master after submit or shelve"),
         ]
-        self.description = "Submit changes from git to the perforce depot."
+        self.description = """Submit changes from git to the perforce depot.\n
+    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.
+
+    One usage scenario is to run unit tests in the hook."""
+
         self.usage += " [name of git branch to submit into perforce depot]"
         self.origin = ""
         self.detectRenames = False
@@ -2303,6 +2309,14 @@ class P4Submit(Command, P4UserMap):
             sys.exit("number of commits (%d) must match number of shelved changelist (%d)" %
                      (len(commits), num_shelves))
 
+        hooks_path = gitConfig("core.hooksPath")
+        if len(hooks_path) <= 0:
+            hooks_path = os.path.join(os.environ.get("GIT_DIR", ".git"), "hooks")
+
+        hook_file = os.path.join(hooks_path, "p4-pre-submit")
+        if os.path.isfile(hook_file) and os.access(hook_file, os.X_OK) and subprocess.call([hook_file]) != 0:
+            sys.exit(1)
+
         #
         # Apply the commits, one at a time.  On failure, ask if should
         # continue to try the rest of the patches, or quit.