Subject: bug#60936: 30.0.50; ERC >5.5: Add erc-fill style based on visual-line-mode

From: "J.P." <[email-masked]>
Date: Thu, 31 Aug 2023 06:31:46 -0700

One of my patches for this feature introduced a corner-case regression
involving the option `erc-echo-timestamps'. If `cursor-sensor-mode' is
somehow enabled outside of this module, then timestamps will still be
echoed even when `erc-echo-timestamps' is nil.

  commit ad3dc74e074719a58226e23a45c4556cd54c0a48
  Author: F. Jason Park <[email-masked]>
  Date:   Wed Nov 24 03:10:20 2021 -0800
  
      Expose insertion time as text prop in erc-stamp
      
      * lisp/erc/erc-stamp.el (erc-add-timestamp): Add new text property
      [...]
      (erc-echo-timestamp): Make interactive and show timestamps even when
      the variable `erc-echo-timestamps' is nil.
      (erc--echo-ts-csf): Add new function to serve as value of
      cursor-sensor function text properties.
      * test/lisp/erc/erc-stamp-tests.el: New file.  (Bug#60936.)
  
   lisp/erc/erc-stamp.el            |  15 ++-
   test/lisp/erc/erc-stamp-tests.el | 207 +++++++++++++++++++++++++++++++++++++++
   2 files changed, 217 insertions(+), 5 deletions(-)

In addition to addressing the above, the attached patch includes a new
optional parameter for the command `erc-echo-timestamp'. It allows for
specifying a timezone for the echoed stamp via prefix argument or a new
option, `erc-echo-timestamp-zone'.

These changes are intended for ERC 5.6.

>From 1ca0862854ff5f926ed45b06cc494aa7f7f2b1b7 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <[email-masked]>
Date: Fri, 25 Aug 2023 19:03:26 -0700
Subject: [PATCH 1/2] [5.6] ; Allow alternate ert-info text in ERC test utility

* test/lisp/erc/erc-tests.el
(erc-tests--assert-printed-in-subprocess): Don't insist that arguments
to the Emacs "-load" invocation option be actual disk files.
* test/lisp/erc/resources/base/assoc/bumped/again.eld: Adjust timeouts.
* test/lisp/erc/resources/base/assoc/bumped/foisted.eld: Adjust timeouts.
* test/lisp/erc/resources/base/assoc/bumped/refoisted.eld: Adjust timeouts.
* test/lisp/erc/resources/base/netid/bouncer/barnet.eld: Adjust timeouts.
* test/lisp/erc/resources/base/netid/bouncer/foonet.eld: Adjust
timeouts.
* test/lisp/erc/resources/base/renick/self/qual-chester.eld: Adjust
timeouts.
* test/lisp/erc/resources/base/renick/self/qual-tester.eld: Adjust
timeouts.
* test/lisp/erc/resources/erc-d/erc-d-t.el
(erc-d-t--wait-message-prefix, erc-d-t-wait-for, erc-d-t-ensure-for):
Add and use new variable to make `ert-info' message prefix adjustable.
The immediate use for this is to make it easier to distinguish between
consecutive assertions in which the first waits for a condition and
the second ensures it holds for some duration.
* test/lisp/erc/resources/erc-d/erc-d-u.el
(erc-d-u--read-exchange-default): Skip killed buffers.
* test/lisp/erc/resources/erc-d/resources/dynamic-barnet.eld: Adjust
timeout.
* test/lisp/erc/resources/erc-d/resources/dynamic-foonet.eld: Adjust
timeouts.
* test/lisp/erc/resources/erc-d/resources/linger.eld: Adjust timeouts.
---
 test/lisp/erc/erc-tests.el                             |  3 +--
 test/lisp/erc/resources/base/assoc/bumped/again.eld    | 10 +++++-----
 test/lisp/erc/resources/base/assoc/bumped/foisted.eld  | 10 +++++-----
 .../lisp/erc/resources/base/assoc/bumped/refoisted.eld |  8 ++++----
 test/lisp/erc/resources/base/netid/bouncer/barnet.eld  |  2 +-
 test/lisp/erc/resources/base/netid/bouncer/foonet.eld  |  2 +-
 .../erc/resources/base/renick/self/qual-chester.eld    |  2 +-
 .../erc/resources/base/renick/self/qual-tester.eld     |  2 +-
 test/lisp/erc/resources/erc-d/erc-d-t.el               |  7 +++++--
 test/lisp/erc/resources/erc-d/erc-d-u.el               |  1 +
 .../erc/resources/erc-d/resources/dynamic-barnet.eld   |  4 ++--
 .../erc/resources/erc-d/resources/dynamic-foonet.eld   |  2 +-
 test/lisp/erc/resources/erc-d/resources/linger.eld     |  4 ++--
 13 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index 9fdad823059..7e01efe95cf 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -2038,8 +2038,7 @@ erc-tests--assert-printed-in-subprocess
          ;; This is for integrations testing with managed configs
          ;; ("starter kits") that use a different package manager.
          (init (and-let* ((found (getenv "ERC_TESTS_INIT"))
-                          (files (split-string found ","))
-                          ((seq-every-p #'file-exists-p files)))
+                          (files (split-string found ",")))
                  (mapcan (lambda (f) (list "-l" f)) files)))
          (prog
           `(progn
diff --git a/test/lisp/erc/resources/base/assoc/bumped/again.eld b/test/lisp/erc/resources/base/assoc/bumped/again.eld
index ab3c7b06214..aef164b6237 100644
--- a/test/lisp/erc/resources/base/assoc/bumped/again.eld
+++ b/test/lisp/erc/resources/base/assoc/bumped/again.eld
@@ -1,10 +1,10 @@
 ;; -*- mode: lisp-data; -*-
-((nick 1 "NICK tester"))
-((user 1 "USER user 0 * :tester")
+((nick 10 "NICK tester"))
+((user 10 "USER user 0 * :tester")
  (0.0 ":irc.foonet.org 433 * tester :Nickname is reserved by a different account")
  (0.0 ":irc.foonet.org FAIL NICK NICKNAME_RESERVED tester :Nickname is reserved by a different account"))
 
-((nick 3 "NICK tester`")
+((nick 10 "NICK tester`")
  (0.1 ":irc.foonet.org 001 tester` :Welcome to the foonet IRC Network tester`")
  (0.0 ":irc.foonet.org 002 tester` :Your host is irc.foonet.org, running version oragono-2.6.1-937b9b02368748e5")
  (0.0 ":irc.foonet.org 003 tester` :This server was created Fri, 24 Sep 2021 01:38:36 UTC")
@@ -21,10 +21,10 @@
  (0.2 ":irc.foonet.org 266 tester` 3 3 :Current global users 3, max 3")
  (0.0 ":irc.foonet.org 422 tester` :MOTD File is missing"))
 
-((mode-user 3.2 "MODE tester` +i")
+((mode-user 10 "MODE tester` +i")
  (0.0 ":irc.foonet.org 221 tester` +i")
  (0.0 ":irc.foonet.org NOTICE tester` :This server is in debug mode and is logging all user I/O. If you do not wish for everything you send to be readable by the server owner(s), please disconnect."))
 
-((privmsg 42.6 "PRIVMSG NickServ :IDENTIFY tester changeme")
+((privmsg 10 "PRIVMSG NickServ :IDENTIFY tester changeme")
  (0.01 ":[email-masked] NICK tester")
  (0.0 ":NickServ!NickServ@localhost NOTICE tester :You're now logged in as tester"))
diff --git a/test/lisp/erc/resources/base/assoc/bumped/foisted.eld b/test/lisp/erc/resources/base/assoc/bumped/foisted.eld
index 5c36e58d9d3..0f7aadac564 100644
--- a/test/lisp/erc/resources/base/assoc/bumped/foisted.eld
+++ b/test/lisp/erc/resources/base/assoc/bumped/foisted.eld
@@ -1,6 +1,6 @@
 ;; -*- mode: lisp-data; -*-
-((nick 1 "NICK tester"))
-((user 1 "USER user 0 * :tester")
+((nick 10 "NICK tester"))
+((user 10 "USER user 0 * :tester")
  (0.0 ":irc.foonet.org 001 tester :Welcome to the foonet IRC Network tester")
  (0.0 ":irc.foonet.org 002 tester :Your host is irc.foonet.org, running version oragono-2.6.1-937b9b02368748e5")
  (0.0 ":irc.foonet.org 003 tester :This server was created Fri, 24 Sep 2021 01:38:36 UTC")
@@ -17,14 +17,14 @@
  (0.0 ":irc.foonet.org 266 tester 3 3 :Current global users 3, max 3")
  (0.0 ":irc.foonet.org 422 tester :MOTD File is missing"))
 
-((mode-user 1.2 "MODE tester +i")
+((mode-user 10 "MODE tester +i")
  (0.0 ":irc.foonet.org 221 tester +i")
  (0.0 ":irc.foonet.org NOTICE tester :This server is in debug mode and is logging all user I/O. If you do not wish for everything you send to be readable by the server owner(s), please disconnect."))
 
-((privmsg 17.21 "PRIVMSG bob :hi")
+((privmsg 10 "PRIVMSG bob :hi")
  (0.02 ":[email-masked] PRIVMSG tester :hola")
  (0.01 ":[email-masked] PRIVMSG tester :how r u?"))
 
-((quit 18.19 "QUIT :" quit)
+((quit 10 "QUIT :" quit)
  (0.01 ":[email-masked] QUIT :Quit: " quit))
 ((drop 1 DROP))
diff --git a/test/lisp/erc/resources/base/assoc/bumped/refoisted.eld b/test/lisp/erc/resources/base/assoc/bumped/refoisted.eld
index 33e4168ac46..63366d3f576 100644
--- a/test/lisp/erc/resources/base/assoc/bumped/refoisted.eld
+++ b/test/lisp/erc/resources/base/assoc/bumped/refoisted.eld
@@ -1,6 +1,6 @@
 ;; -*- mode: lisp-data; -*-
-((nick 1 "NICK tester"))
-((user 1 "USER user 0 * :tester")
+((nick 10 "NICK tester"))
+((user 10 "USER user 0 * :tester")
  (0.1 ":irc.foonet.org 001 dummy :Welcome to the foonet IRC Network dummy")
  (0.0 ":irc.foonet.org 002 dummy :Your host is irc.foonet.org, running version oragono-2.6.1-937b9b02368748e5")
  (0.0 ":irc.foonet.org 003 dummy :This server was created Fri, 24 Sep 2021 01:38:36 UTC")
@@ -22,10 +22,10 @@
  (0.01 ":[email-masked] PRIVMSG dummy :back?")
  )
 
-((mode-user 1.2 "MODE dummy +i")
+((mode-user 10 "MODE dummy +i")
  (0.0 ":irc.foonet.org 221 dummy +i")
  (0.0 ":irc.foonet.org NOTICE dummy :This server is in debug mode and is logging all user I/O. If you do not wish for everything you send to be readable by the server owner(s), please disconnect."))
 
-((renick 42.6 "NICK tester")
+((renick 10 "NICK tester")
  (0.01 ":[email-masked] NICK tester")
  (0.0 ":NickServ!NickServ@localhost NOTICE dummy :You're now logged in as tester"))
diff --git a/test/lisp/erc/resources/base/netid/bouncer/barnet.eld b/test/lisp/erc/resources/base/netid/bouncer/barnet.eld
index 204d01fef77..596383c2699 100644
--- a/test/lisp/erc/resources/base/netid/bouncer/barnet.eld
+++ b/test/lisp/erc/resources/base/netid/bouncer/barnet.eld
@@ -38,4 +38,4 @@
  (0.05 ":[email-masked] PRIVMSG #chan :mike: As he regards his aged father's life.")
  (0.05 ":[email-masked] PRIVMSG #chan :joe: It is a rupture that you may easily heal; and the cure of it not only saves your brother, but keeps you from dishonor in doing it."))
 
-((linger 1 LINGER))
+((linger 2 LINGER))
diff --git a/test/lisp/erc/resources/base/netid/bouncer/foonet.eld b/test/lisp/erc/resources/base/netid/bouncer/foonet.eld
index 4445350ca0c..2e1a3ac27da 100644
--- a/test/lisp/erc/resources/base/netid/bouncer/foonet.eld
+++ b/test/lisp/erc/resources/base/netid/bouncer/foonet.eld
@@ -43,4 +43,4 @@
  (0.1 ":[email-masked] PRIVMSG #chan :bob: Orlando, my liege; the youngest son of Sir Rowland de Boys.")
  (0.1 ":[email-masked] PRIVMSG #chan :alice: The ape is dead, and I must conjure him."))
 
-((linger 1 LINGER))
+((linger 2 LINGER))
diff --git a/test/lisp/erc/resources/base/renick/self/qual-chester.eld b/test/lisp/erc/resources/base/renick/self/qual-chester.eld
index 75b50fe68bd..a224e0451d7 100644
--- a/test/lisp/erc/resources/base/renick/self/qual-chester.eld
+++ b/test/lisp/erc/resources/base/renick/self/qual-chester.eld
@@ -18,7 +18,7 @@
  (0 ":irc.foonet.org 266 chester 3 4 :Current global users 3, max 4")
  (0 ":irc.foonet.org 422 chester :MOTD File is missing"))
 
-((mode-user 1.2 "MODE chester +i")
+((mode-user 10 "MODE chester +i")
  (0 ":irc.foonet.org 221 chester +i")
  (0 ":irc.foonet.org NOTICE chester :This server is in debug mode and is logging all user I/O. If you do not wish for everything you send to be readable by the server owner(s), please disconnect."))
 
diff --git a/test/lisp/erc/resources/base/renick/self/qual-tester.eld b/test/lisp/erc/resources/base/renick/self/qual-tester.eld
index 25199226658..27061c65223 100644
--- a/test/lisp/erc/resources/base/renick/self/qual-tester.eld
+++ b/test/lisp/erc/resources/base/renick/self/qual-tester.eld
@@ -18,7 +18,7 @@
  (0 ":irc.foonet.org 266 tester 4 4 :Current global users 4, max 4")
  (0 ":irc.foonet.org 422 tester :MOTD File is missing"))
 
-((mode-user 1.2 "MODE tester +i")
+((mode-user 10 "MODE tester +i")
  (0 ":irc.foonet.org 221 tester +i")
  (0 ":irc.foonet.org NOTICE tester :This server is in debug mode and is logging all user I/O. If you do not wish for everything you send to be readable by the server owner(s), please disconnect."))
 
diff --git a/test/lisp/erc/resources/erc-d/erc-d-t.el b/test/lisp/erc/resources/erc-d/erc-d-t.el
index 7b2adf4f07b..cf869fb3c70 100644
--- a/test/lisp/erc/resources/erc-d/erc-d-t.el
+++ b/test/lisp/erc/resources/erc-d/erc-d-t.el
@@ -83,6 +83,8 @@ erc-d-t-with-cleanup
                (ignore-errors (kill-buffer buf)))))
          (sleep-for erc-d-t-cleanup-sleep-secs)))))
 
+(defvar erc-d-t--wait-message-prefix "Awaiting: ")
+
 (defmacro erc-d-t-wait-for (max-secs msg &rest body)
   "Wait for BODY to become non-nil.
 Or signal error with MSG after MAX-SECS.  When MAX-SECS is negative,
@@ -99,7 +101,7 @@ erc-d-t-wait-for
   (let ((inverted (make-symbol "inverted"))
         (time-out (make-symbol "time-out"))
         (result (make-symbol "result")))
-    `(ert-info ((concat "Awaiting: " ,msg))
+    `(ert-info ((concat erc-d-t--wait-message-prefix ,msg))
        (let ((,time-out (abs ,max-secs))
              (,inverted (< ,max-secs 0))
              (,result ',result))
@@ -120,7 +122,8 @@ erc-d-t-ensure-for
   (unless (or (stringp msg) (memq (car-safe msg) '(format concat)))
     (push msg body)
     (setq msg (prin1-to-string body)))
-  `(erc-d-t-wait-for (- (abs ,max-secs)) ,msg (not (progn ,@body))))
+  `(let ((erc-d-t--wait-message-prefix "Sustaining: "))
+     (erc-d-t-wait-for (- (abs ,max-secs)) ,msg (not (progn ,@body)))))
 
 (defun erc-d-t-search-for (timeout text &optional from on-success)
   "Wait for TEXT to appear in current buffer before TIMEOUT secs.
diff --git a/test/lisp/erc/resources/erc-d/erc-d-u.el b/test/lisp/erc/resources/erc-d/erc-d-u.el
index e26fa8b47dd..c7d6859e3e1 100644
--- a/test/lisp/erc/resources/erc-d/erc-d-u.el
+++ b/test/lisp/erc/resources/erc-d/erc-d-u.el
@@ -74,6 +74,7 @@ erc-d-u--read-exchange-default
   (let ((hunks (erc-d-u-scan-e-sd info))
         (pos (erc-d-u-scan-e-pos info)))
     (or (and (erc-d-u-scan-d-hunks hunks)
+             (buffer-live-p (erc-d-u-scan-d-buf hunks))
              (with-current-buffer (erc-d-u-scan-d-buf hunks)
                (goto-char pos)
                (condition-case _err
diff --git a/test/lisp/erc/resources/erc-d/resources/dynamic-barnet.eld b/test/lisp/erc/resources/erc-d/resources/dynamic-barnet.eld
index 4994e9c5503..e8feb2e6fd8 100644
--- a/test/lisp/erc/resources/erc-d/resources/dynamic-barnet.eld
+++ b/test/lisp/erc/resources/erc-d/resources/dynamic-barnet.eld
@@ -18,14 +18,14 @@
  (0. ":irc.barnet.org 266 tester 3 3 :Current global users 3, max 3")
  (0. ":irc.barnet.org 422 tester :MOTD File is missing"))
 
-((mode-user 1.2 "MODE tester +i")
+((mode-user 2 "MODE tester +i")
  (0. ":irc.barnet.org 221 tester +Zi")
  (0. ":irc.barnet.org 306 tester :You have been marked as being away")
  (0 ":[email-masked] JOIN #chan")
  (0 ":irc.barnet.org 353 joe = #chan :[email-masked] @[email-masked]")
  (0 ":irc.barnet.org 366 joe #chan :End of NAMES list"))
 
-((mode 1 "MODE #chan")
+((mode 3 "MODE #chan")
  (0 ":irc.barnet.org 324 tester #chan +nt")
  (0 ":irc.barnet.org 329 tester #chan 1620805269")
  (0.1 ":[email-masked] PRIVMSG #chan :mike: Yes, a dozen; and as many to the vantage, as would store the world they played for.")
diff --git a/test/lisp/erc/resources/erc-d/resources/dynamic-foonet.eld b/test/lisp/erc/resources/erc-d/resources/dynamic-foonet.eld
index a47998e7d32..4855c178861 100644
--- a/test/lisp/erc/resources/erc-d/resources/dynamic-foonet.eld
+++ b/test/lisp/erc/resources/erc-d/resources/dynamic-foonet.eld
@@ -17,7 +17,7 @@
  (0. ":irc.foonet.org 266 tester 3 3 :Current global users 3, max 3")
  (0. ":irc.foonet.org 422 tester :MOTD File is missing"))
 
-((mode-user 1.2 "MODE tester +i")
+((mode-user 2 "MODE tester +i")
  (0. ":irc.foonet.org 221 tester +Zi")
  (0. ":irc.foonet.org 306 tester :You have been marked as being away")
  (0 ":[email-masked] JOIN #chan")
diff --git a/test/lisp/erc/resources/erc-d/resources/linger.eld b/test/lisp/erc/resources/erc-d/resources/linger.eld
index 36c81a3af4b..e456370a800 100644
--- a/test/lisp/erc/resources/erc-d/resources/linger.eld
+++ b/test/lisp/erc/resources/erc-d/resources/linger.eld
@@ -20,14 +20,14 @@
  (0 ":irc.example.org 266 tester 3 3 :Current global users 3, max 3")
  (0 ":irc.example.org 422 tester :MOTD File is missing"))
 
-((mode-user 1.2 "MODE tester +i")
+((mode-user 2 "MODE tester +i")
  (0 ":irc.example.org 221 tester +Zi")
  (0 ":irc.example.org 306 tester :You have been marked as being away")
  (0 ":tester!~tester@localhost JOIN #chan")
  (0 ":irc.example.org 353 alice = #chan :[email-masked] @[email-masked]")
  (0 ":irc.example.org 366 alice #chan :End of NAMES list"))
 
-((mode-chan 1.2 "MODE #chan")
+((mode-chan 2 "MODE #chan")
  (0 ":[email-masked] PRIVMSG #chan :hey"))
 
 ((linger 1.0 LINGER))
-- 
2.41.0

>From 9a5b2bd7e9ce32bafbb3f204cc1b4a7d5069e9e5 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <[email-masked]>
Date: Wed, 30 Aug 2023 23:15:22 -0700
Subject: [PATCH 2/2] [5.6] Add optional timezone param to erc-echo-timestamp

* etc/ERC-NEWS: Mention option `erc-echo-timestamp-zone'.
* lisp/erc/erc-stamp.el (erc-echo-timestamps): Mention that some
finagling is required if enabling this option after activating the
module.
(erc-echo-timestamp-format): Add additional Custom choice constants.
(erc-echo-timestamp-zone): New option to specify timezone for option
`erc-echo-timestamps' and function `erc-echo-timestamp'.
(erc-stamp-mode, erc-stamp-enable, erc-stamp-disable): Call
`erc-stamp--setup' instead of `erc-munge-invisibility-spec'.
(erc-munge-invisibility-spec): Perform teardown when boolean flag
options, like `erc-timestamp-intangible' and `erc-echo-timestamps' are
nil.
(erc-stamp--setup): Call `erc-munge-invisibility-spec).
(erc-stamp--last-stamp, erc-stamp--on-clear-message): New function and
helper state variable to tell Emacs not to clear the current timestamp
message when navigating within the same IRC message.
(erc-echo-timestamp): Add optional `zone' parameter, to be passed
directly to `format-time-string', when non-interactive, and massaged
sensibly otherwise.  Set the local variable `erc-stamp--last-stamp'.
* test/lisp/erc/erc-stamp-tests.el (erc-echo-timestamp): New test.
(Bug#60936)
---
 etc/ERC-NEWS                     | 13 +++--
 lisp/erc/erc-stamp.el            | 83 ++++++++++++++++++++++++++------
 test/lisp/erc/erc-stamp-tests.el | 30 ++++++++++++
 3 files changed, 107 insertions(+), 19 deletions(-)

diff --git a/etc/ERC-NEWS b/etc/ERC-NEWS
index 7ee55982b17..69088732c0d 100644
--- a/etc/ERC-NEWS
+++ b/etc/ERC-NEWS
@@ -203,11 +203,18 @@ continued integration.  With the existing design, merely loading the
 library 'erc-log' caused 'truncate' to start writing logs, possibly
 against a user's wishes.
 
+** The function 'erc-echo-timestamp' is now a command.
+The option 'erc-echo-timestamps' (plural) enables the contextual
+echoing of timestamps to the echo area when moving between messages in
+an ERC buffer.  This functionality is now available on demand by
+invoking the newly interactive function 'erc-echo-timestamp' atop any
+message.  And the new companion option 'erc-echo-timestamp-zone'
+determines the default timezone when not specified with a prefix
+argument.
+
 ** Miscellaneous UX changes.
 Some minor quality-of-life niceties have finally made their way to
-ERC.  For example, the function 'erc-echo-timestamp' is now
-interactive and can be invoked on any message to view its timestamp in
-the echo area.  Fool visibility has become togglable with the new
+ERC.  For example, fool visibility has become togglable with the new
 command 'erc-match-toggle-hidden-fools'.  The 'button' module's
 'erc-button-previous' now moves to the beginning instead of the end of
 buttons.  A new command, 'erc-news', can be invoked to visit this very
diff --git a/lisp/erc/erc-stamp.el b/lisp/erc/erc-stamp.el
index a021cd26607..be12d6080d2 100644
--- a/lisp/erc/erc-stamp.el
+++ b/lisp/erc/erc-stamp.el
@@ -136,14 +136,27 @@ erc-echo-timestamps
   "If non-nil, print timestamp in the minibuffer when point is moved.
 Using this variable, you can turn off normal timestamping,
 and simply move point to an irc message to see its timestamp
-printed in the minibuffer."
+printed in the minibuffer.  When attempting to enable this option
+after `erc-stamp-mode' is already active, you may need to run the
+command `erc-show-timestamps', `erc-hide-timestamps', or similar
+in the appropriate ERC buffer."
   :type 'boolean)
 
 (defcustom erc-echo-timestamp-format "Timestamped %A, %H:%M:%S"
   "Format string to be used when `erc-echo-timestamps' is non-nil.
 This string specifies the format of the timestamp being echoed in
 the minibuffer."
-  :type 'string)
+  :type '(choice (const "Timestamped %A, %H:%M:%S")
+                 (const  "%Y-%m-%d %H:%M:%S %Z")
+                 string))
+
+(defcustom erc-echo-timestamp-zone nil
+  "Default timezone for the option `erc-echo-timestamps'.
+Also affects the command `erc-echo-timestamp' (singular).  See
+the ZONE parameter of `format-time-string' for a description of
+acceptable value types."
+  :type '(choice boolean number (const wall) (list number string))
+  :package-version '(ERC . "5.6")) ; FIXME sync on release
 
 (defcustom erc-timestamp-intangible nil
   "Whether the timestamps should be intangible, i.e. prevent the point
@@ -167,14 +180,16 @@ stamp
    (add-hook 'erc-send-modify-hook #'erc-add-timestamp 60)
    (add-hook 'erc-mode-hook #'erc-stamp--recover-on-reconnect)
    (add-hook 'erc--pre-clear-functions #'erc-stamp--reset-on-clear)
-   (unless erc--updating-modules-p
-     (erc-buffer-do #'erc-munge-invisibility-spec)))
+   (unless erc--updating-modules-p (erc-buffer-do #'erc-stamp--setup)))
   ((remove-hook 'erc-mode-hook #'erc-munge-invisibility-spec)
    (remove-hook 'erc-insert-modify-hook #'erc-add-timestamp)
    (remove-hook 'erc-send-modify-hook #'erc-add-timestamp)
    (remove-hook 'erc-mode-hook #'erc-stamp--recover-on-reconnect)
    (remove-hook 'erc--pre-clear-functions #'erc-stamp--reset-on-clear)
    (erc-with-all-buffers-of-server nil nil
+     (let (erc-echo-timestamps erc-hide-timestamps erc-timestamp-intangible)
+       (erc-stamp--setup))
+     (kill-local-variable 'erc-stamp--last-stamp)
      (kill-local-variable 'erc-timestamp-last-inserted)
      (kill-local-variable 'erc-timestamp-last-inserted-left)
      (kill-local-variable 'erc-timestamp-last-inserted-right))))
@@ -640,14 +655,31 @@ erc-format-timestamp
 ;; please modify this function and move it to a more appropriate
 ;; location.
 (defun erc-munge-invisibility-spec ()
-  (and erc-timestamp-intangible (not (bound-and-true-p cursor-intangible-mode))
-       (cursor-intangible-mode 1))
-  (and erc-echo-timestamps (not (bound-and-true-p cursor-sensor-mode))
-       (cursor-sensor-mode 1))
+  (if erc-timestamp-intangible
+      (cursor-intangible-mode +1) ; idempotent
+    (when (bound-and-true-p cursor-intangible-mode)
+      (cursor-intangible-mode -1)))
+  (if erc-echo-timestamps
+      (progn
+        (cursor-sensor-mode +1) ; idempotent
+        (when (<= 29 emacs-major-version)
+          (add-function :before-until (local 'clear-message-function)
+                        #'erc-stamp--on-clear-message)))
+    (when (bound-and-true-p cursor-sensor-mode)
+      (cursor-sensor-mode -1))
+    (remove-function (local 'clear-message-function)
+                     #'erc-stamp--on-clear-message))
   (if erc-hide-timestamps
       (add-to-invisibility-spec 'timestamp)
     (remove-from-invisibility-spec 'timestamp)))
 
+(defun erc-stamp--setup ()
+  "Enable or disable buffer-local `erc-stamp-mode' modifications."
+  (if erc-stamp-mode
+      (erc-munge-invisibility-spec)
+    (let (erc-echo-timestamps erc-hide-timestamps erc-timestamp-intangible)
+      (erc-munge-invisibility-spec))))
+
 (defun erc-hide-timestamps ()
   "Hide timestamp information from display."
   (interactive)
@@ -677,14 +709,33 @@ erc-toggle-timestamps
 	    (erc-munge-invisibility-spec)))
 	(erc-buffer-list)))
 
-(defun erc-echo-timestamp (dir stamp)
-  "Print timestamp text-property of an IRC message."
-  ;; Could also pass an &optional `zone' arg to `format-time-string'.
-  (interactive (list 'entered (get-text-property (point) 'erc-timestamp)))
-  (when (eq 'entered dir)
-    (when stamp
-      (message "%s" (format-time-string erc-echo-timestamp-format
-					stamp)))))
+(defvar-local erc-stamp--last-stamp nil)
+
+(defun erc-stamp--on-clear-message (&rest _)
+  "Return `dont-clear-message' when operating inside the same stamp."
+  (and erc-stamp--last-stamp erc-echo-timestamps
+       (eq (get-text-property (point) 'erc-timestamp) erc-stamp--last-stamp)
+       'dont-clear-message))
+
+(defun erc-echo-timestamp (dir stamp &optional zone)
+  "Display timestamp of message at point in echo area.
+Interactively, interpret a numeric prefix as a ZONE offset in
+hours (or seconds, if its abs value is larger than 14), and
+interpret a \"raw\" prefix as UTC.  To specify a zone for use
+with the option `erc-echo-timestamps', see the companion option
+`erc-echo-timestamp-zone'."
+  (interactive (list nil (get-text-property (point) 'erc-timestamp)
+                     (pcase current-prefix-arg
+                       ((and (pred numberp) v)
+                        (if (<= (abs v) 14) (* v 3600) v))
+                       (`(,_) t))))
+  (if (and stamp (or (null dir) (and erc-echo-timestamps (eq 'entered dir))))
+      (progn
+        (setq erc-stamp--last-stamp stamp)
+        (message (format-time-string erc-echo-timestamp-format
+                                     stamp (or zone erc-echo-timestamp-zone))))
+    (when (and erc-echo-timestamps (eq 'left dir))
+      (setq erc-stamp--last-stamp nil))))
 
 (defun erc--echo-ts-csf (_window _before dir)
   (erc-echo-timestamp dir (get-text-property (point) 'erc-timestamp)))
diff --git a/test/lisp/erc/erc-stamp-tests.el b/test/lisp/erc/erc-stamp-tests.el
index c448416cd69..b00aa6dcabf 100644
--- a/test/lisp/erc/erc-stamp-tests.el
+++ b/test/lisp/erc/erc-stamp-tests.el
@@ -274,4 +274,34 @@ erc-timestamp-intangible--left
       (when noninteractive
         (kill-buffer)))))
 
+(ert-deftest erc-echo-timestamp ()
+  (should-not erc-echo-timestamps)
+  (should-not erc-stamp--last-stamp)
+  (insert (propertize "abc" 'erc-timestamp 433483200))
+  (goto-char (point-min))
+  (let ((inhibit-message t)
+        (erc-echo-timestamp-format "%Y-%m-%d %H:%M:%S %Z")
+        (erc-echo-timestamp-zone (list (* 60 60 -4) "EDT")))
+
+    ;; No-op when non-interactive and option is nil
+    (should-not (erc--echo-ts-csf nil nil 'entered))
+    (should-not erc-stamp--last-stamp)
+
+    ;; Non-interactive (cursor sensor function)
+    (let ((erc-echo-timestamps t))
+      (should (equal (erc--echo-ts-csf nil nil 'entered)
+                     "1983-09-27 00:00:00 EDT")))
+    (should (= 433483200 erc-stamp--last-stamp))
+
+    ;; Interactive
+    (should (equal (call-interactively #'erc-echo-timestamp)
+                   "1983-09-27 00:00:00 EDT"))
+    ;; Interactive with zone
+    (let ((current-prefix-arg '(4)))
+      (should (equal (call-interactively #'erc-echo-timestamp)
+                     "1983-09-27 04:00:00 GMT")))
+    (let ((current-prefix-arg -7))
+      (should (equal (call-interactively #'erc-echo-timestamp)
+                     "1983-09-26 21:00:00 -07")))))
+
 ;;; erc-stamp-tests.el ends here
-- 
2.41.0