Add notes about "action stamps"

1 files changed, 48 insertions, 2 deletions

diff --git a/itches/emacs/development.org b/itches/emacs/development.org
index b151179..91a0109 100644
--- a/itches/emacs/development.org
+++ b/itches/emacs/development.org
@@ -1,7 +1,7 @@
 Stuff that could make work on Emacs itself more smooth.
 
 * Changelog
-** action-stamps
+** Action stamps
 I don't know any function to
 
 1. generate them from a Git commit, a *vc-change-log* buffer…
@@ -23,8 +23,54 @@ Except that [[https://tools.ietf.org/html/rfc3339][RFC3339]] says:
 
 While ~%z~ yields "+hhmm" or "-hhmm".  Also [[http://esr.ibiblio.org/?p=3872][ESR wants Zulu time]].
 
-See bug#20609.
+See also
+- bug#20609
+- https://lists.gnu.org/archive/html/emacs-devel/2014-09/msg00252.html
 
+This monstrosity does the job:
+#+begin_src elisp
+(defun my/revision-at-point ()
+  (cond
+   ;; TODO: add vc support.
+   ((derived-mode-p 'magit-mode)
+    (magit-branch-or-commit-at-point))))
+
+(eval-when-compile
+  ;; Load rx's pcase pattern.
+  (require 'rx))
+
+(defun my/action-stamp-at-point (rev)
+  (interactive
+   (list
+    (let* ((rev (my/revision-at-point))
+           (prompt (if rev (format "Revision? (%s) " rev) "Revision? ")))
+      (read-string prompt nil nil rev))))
+  (let* ((cmd "git show --no-patch --date=unix --format='%ad!%ae'")
+         (git-info (shell-command-to-string (format "%s %s" cmd rev))))
+    (pcase git-info
+      ((rx (let timestamp-str (+ digit))
+           "!"
+           (let mail (+ anychar))
+           "\n")
+       (let* ((timestamp (string-to-number timestamp-str))
+              (date (format-time-string "%FT%TZ" timestamp t))
+              (action-stamp (format "%s!%s" date mail)))
+         (kill-new action-stamp)
+         (message action-stamp))))))
+#+end_src
+
+ESR's =git stamp= alias in [[https://gitlab.com/esr/reposurgeon/-/blob/4.5/reposurgeon-git-aliases][reposurgeon]]:
+#+begin_src conf
+	# git stamp <commit-ish> - print a reposurgeon-style action stamp
+	# This always goes to the committer. It would be better to look at thwe author
+	# timestamp first and fall back to commmitter, because the author stamp because 
+	# doesn't change when patches  are replayed onto a repository, while the commit
+	# stamp will. 
+	stamp = show -s --format='%cI!%ce'
+#+end_src
+This alias seems to confirm my feeling that Zulu time is not worth
+bothering with: ISO 8601 is just as machine-parseable, and the
+timezone bit actually conveys meaning to a human reader.
 * Bug tracker
 ** Asynchronous client
 It would be wonderful if ~debbugs-gnu~ and ~debbugs-gnu-search~ used