bug#20609: 25.0.50; How to I easily generate the "action stamp" given a commit hash?

[Noam Postavsky]

Dmitry Gutov <dgutov@yandex.ru> writes:

> CONTRIBUTE prohibits referencing commits the easy way, and instead asks
> me to use "RFC3339 date followed by followed by the committer's email".
>
> If reversing this decision is not an option

I would like to propose doing away with this "action stamp" thing.  It
is okay for its original purpose: an almost-guaranteed-unique identifier
for an automated repository format conversion tool.  But it is not very
human-readable.  It is fairly awkward to come up with a git command that
comes up with the correct UTC timestamp.  We hardly use it anyway.

Giving just the date (no timestamp) plus summary line should be unique
enough, and is very human readable.

>From e2bfcc9f9a51e33215d30d4226216c029c182ec3 Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Mon, 27 Nov 2017 07:56:39 -0500
Subject: [PATCH] * CONTRIBUTE: Don't recommend action stamps (Bug#20609).

---
 CONTRIBUTE | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/CONTRIBUTE b/CONTRIBUTE
index c324375bb0..79c127fbdc 100644
--- a/CONTRIBUTE
+++ b/CONTRIBUTE
@@ -232,10 +232,9 @@ them right the first time, so here are guidelines for 
formatting them:
   switches to a different VCS.  So we recommend against that.
 
   One way to identify revisions is by quoting their summary line.
-  Another is with an action stamp - an RFC3339 date followed by !
-  followed by the committer's email - for example,
-  "2014-01-16T05:43:35Z!esr@thyrsus.com".  Often, "my previous commit"
-  will suffice.
+  Prefixing the summary with the commit date can give useful context
+  (use 'git show -s "--pretty=format:%cd \"%s\"" --date=short HASH' to
+  produce that).  Often, "my previous commit" will suffice.
 
 - There is no need to mention files such as NEWS and MAINTAINERS, or
   to indicate regeneration of files such as 'lib/gnulib.mk', in the
-- 
2.11.0