* doc/misc/erc.texi: Minor tweak in SASL section.
* etc/ERC-NEWS: Revise various sections under 5.6.
* lisp/erc/erc-button.el (erc-button-alist): Remove comment.
(erc-nick-popup-alist): Remove comment.
* lisp/erc/erc-fill.el (erc-fill-wrap-margin-width): Remove comment.
(erc-fill-wrap-margin-side): Remove comment.
(erc-fill-line-spacing): Remove comment.
(erc-fill-wrap-use-pixels): Remove comment.
(erc-fill-wrap-visual-keys): Remove comment.
(erc-fill-wrap-force-screen-line-movement): Remove comment.
(erc-fill-wrap-merge): Remove comment.
* lisp/erc/erc-goodies.el (erc-scrolltobottom-all): Remove comment.
(erc-keep-place-indicator-style): Remove comment.
(erc-keep-place-indicator-buffer-type): Remove comment.
(erc-keep-place-indicator-follow): Remove comment.
* lisp/erc/erc-networks.el (erc-server-alist): Remove comment.
* lisp/erc/erc-nicks.el (erc-nicks): Remove comment.
* lisp/erc/erc-speedbar.el
(erc-speedbar-nicknames-window-width): Remove comment.
(erc-speedbar-hide-mode-topic): Remove comment.
(erc-speedbar-my-nick-face): Remove comment.
* lisp/erc/erc-stamp.el (erc-timestamp-format-right): Remove comment.
(erc-echo-timestamp-zone): Remove comment.
(erc-timestamp-use-align-to): Remove comment.
* lisp/erc/erc-status-sidebar.el
(erc-status-sidebar-highlight-active-buffer): Remove comment.
(erc-status-sidebar-style): Remove comment.
(erc-status-sidebar-click-display-action): Remove comment.
* lisp/erc/erc.el: Bump required Compat version to 29.1.4.3 in
Package-Requires header.
(erc-notice-face): Remove comment.
(erc-action-face): Remove comment.
(erc-interactive-display): Remove comment.
(erc-auto-reconnect-display-timeout): Remove comment.
(erc-reconnect-display-server-buffers): Remove comment.
(erc-modules): Remove comment.
* test/lisp/erc/resources/base/display-message/multibuf.eld: Remove
reference to specific ERC version in QUIT command reason.
* test/lisp/erc/resources/base/assoc/reconplay/foonet.eld: Timeout.

* lisp/erc/erc.el (erc--insert-marker): New internal variable for
overriding `erc-insert-marker' when displaying messages at a
non-default location in the buffer.
(erc-display-line-1): Favor `erc--insert-marker' over
`erc-insert-marker' when non-nil.
; * test/lisp/erc/resources/base/assoc/multi-net/barnet.eld: Timeouts.
; * test/lisp/erc/resources/base/assoc/multi-net/foonet.eld: Timeouts.
; * test/lisp/erc/resources/base/netid/bouncer/barnet-drop.eld: Timeouts.
; * test/lisp/erc/resources/base/netid/bouncer/foonet-drop.eld: Timeouts.
; * test/lisp/erc/resources/erc-d/resources/dynamic-foonet.eld: Timeouts.
; * test/lisp/erc/resources/sasl/scram-sha-1.eld: Timeouts.
; * test/lisp/erc/resources/sasl/scram-sha-256.eld: Timeouts.

* 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/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/erc-d.el: Typo.
* test/lisp/erc/resources/base/assoc/bouncer-history/barnet.eld: Timeouts.
* test/lisp/erc/resources/base/assoc/bouncer-history/foonet.eld: Timeouts.
* test/lisp/erc/resources/base/assoc/bumped/again.eld: Timeouts.
* test/lisp/erc/resources/base/assoc/bumped/foisted.eld: Timeouts.
* test/lisp/erc/resources/base/assoc/bumped/refoisted.eld: Timeouts.
* test/lisp/erc/resources/base/flood/soju.eld: Timeouts.
* test/lisp/erc/resources/base/netid/bouncer/barnet.eld: Timeouts.
* test/lisp/erc/resources/base/netid/bouncer/foonet.eld: Timeouts.
* test/lisp/erc/resources/base/reconnect/aborted-dupe.eld: Timeouts.
* test/lisp/erc/resources/base/reconnect/aborted.eld: Timeouts.
* test/lisp/erc/resources/base/renick/self/qual-chester.eld: Timeouts.
* test/lisp/erc/resources/base/renick/self/qual-tester.eld: Timeouts.
* test/lisp/erc/resources/erc-d/resources/dynamic-barnet.eld: Timeouts.
* test/lisp/erc/resources/erc-d/resources/dynamic-foonet.eld: Timeouts.
* test/lisp/erc/resources/erc-d/resources/linger.eld: Timeouts.
* test/lisp/erc/resources/join/legacy/foonet.eld: Timeouts.

* lisp/erc/erc-button.el (erc-button-mode, erc-button-enable): Warn if
`erc-button-alist' contains deprecated FORM field in `nicknames'
entry.
(erc-button-alist): Discourage arbitrary sexp form for third item of
entries and offer more useful bounds-modifying function in its place.
Mention that anything other than `erc-button-buttonize-nicks' is
deprecated as the FORM field in a `nicknames' entry.  Bump
package-version even though this doesn't introduce a visible change in
the default value.
(erc-button--maybe-warn-arbitrary-sexp): Add helper for validating
third `erc-button-alist' field.
(erc-button--check-nicknames-entry): Add helper to check for
deprecated items in `erc-button-alist'.
(erc-button--preserve-bounds): Add function to serve as default value
for `erc-button--modify-nick-function).
(erc-button--modify-nick-function): Add new variable to hold a
function that filters nickname bounds when buttonizing.
(erc-button--phantom-users, erc-button--add-phantom-speaker,
erc-button--phantom-users-mode): Add new internal minor mode for
treating unseen speakers of PRIVMSGs as known members of the server
for things like coloring nicks during buffer playback.
(erc-button--get-user-from-speaker-naive): Add temporary utility
function to scrape nick from speaker in narrowed buffer.  This will be
replaced by an account-aware version in next major ERC release.
(erc-button-add-nickname-buttons): Accommodate function variant for
"form" field of `erc-button-alist' entries.  Minor optimizations.
This function will likely become the primary juncture for applying
text properties that support nickname-related user-intelligence
features.
(erc-button-add-buttons-1): Show warning when arbitrary sexp for third
"form" field encountered.  Accommodate binary function instead.
(erc-button--substitute-command-keys-in-region): Add helper function
for applying key substitutions in ERC warning messages.
(erc-button--display-error-notice-with-keys): Add new helper function
for displaying ad hoc warnings that possibly require key substitution.
(erc-button--display-error-notice-with-keys-and-warn): Add variant of
`erc-button--display-error-notice-with-keys' that also emits warnings.
* lisp/erc/erc-networks.el (erc-networks--ensure-announced,
erc-networks--on-MOTD-end): Use new key-substitutions helper from
erc-button.
* test/lisp/erc/erc-tests.el
(erc-button--display-error-notice-with-keys): New test.
* test/lisp/erc/resources/base/assoc/bouncer-history/foonet.eld: Add
unknown speaker in channel for phantom store to handle.  Currently
requires manual intervention to leverage.  (Bug#60933.)

* lisp/erc/erc-networks.el
(erc-networks-rename-surviving-target-buffer): Don't kill a surviving
target buffer when another, non-target buffer, possibly not even
belonging to ERC, already exists and sports the target's name.
(erc-networks--reconcile-buffer-names): Always append a network-ID
suffix to a target buffer's name if another buffer of that name
already exists.  (Bug#59976.)
* lisp/erc/erc.el (erc, erc-tls): Revise `:id' portion of doc strings.
Thanks to Mike Kazantsev for the suggestion and for filing this bug
and helping solve it.
* test/lisp/erc/erc-networks-tests.el:
(erc-networks-rename-surviving-target-buffer--query-non-target): Add
new test.
* test/lisp/erc/erc-scenarios-base-association-query.el: New file.
* test/lisp/erc/resources/base/assoc/queries/netnick.eld: New file.
* test/lisp/erc/resources/base/assoc/queries/non-erc.eld: New file.

* test/lisp/erc/resources/base/assoc/samenet/chester.eld: Relax timeout.
* test/lisp/erc/resources/base/assoc/samenet/tester.eld: Relax timeout.
* test/lisp/erc/resources/base/assoc/samenet/tester2.eld: Relax timeout.
* test/lisp/erc/resources/base/netid/samenet/chester.eld: Relax timeout.
* test/lisp/erc/resources/base/netid/samenet/tester.eld: Relax timeout.
* test/lisp/erc/resources/erc-d/erc-d-tests.el (erc-d-run-linger,
erc-d-run-linger-fail, erc-d-run-linger-direct): Mark some tests as
being unstable.

* test/lisp/erc/erc-scenarios-base-association-nick.el: New file.
* test/lisp/erc/erc-scenarios-base-association-samenet.el: New file.
* test/lisp/erc/erc-scenarios-base-association.el: New file.
* test/lisp/erc/erc-scenarios-base-compat-rename-bouncer.el: New file.
* test/lisp/erc/erc-scenarios-base-misc-regressions.el: New file.
* test/lisp/erc/erc-scenarios-base-netid-bouncer-id.el: New file.
* test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-base.el: New file.
* test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-both.el: New file.
* test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-id.el: New file.
* test/lisp/erc/erc-scenarios-base-netid-bouncer.el: New file.
* test/lisp/erc/erc-scenarios-base-netid-samenet.el: New file.
* test/lisp/erc/erc-scenarios-base-reconnect.el: New file.
* test/lisp/erc/erc-scenarios-base-renick.el: New file.
* test/lisp/erc/erc-scenarios-base-reuse-buffers.el: New file.
* test/lisp/erc/erc-scenarios-base-unstable.el: New file.
* test/lisp/erc/erc-scenarios-base-upstream-recon-soju.el: New file.
* test/lisp/erc/erc-scenarios-base-upstream-recon-znc.el: New file.
* test/lisp/erc/erc-scenarios-misc.el: New file.
* test/lisp/erc/erc-scenarios-services-misc.el: New file.
* test/lisp/erc/resources/base/assoc/bouncer-history/barnet.eld: New file.
* test/lisp/erc/resources/base/assoc/bouncer-history/foonet.eld: New file.
* test/lisp/erc/resources/base/assoc/bumped/again.eld: New file.
* test/lisp/erc/resources/base/assoc/bumped/foisted.eld: New file.
* test/lisp/erc/resources/base/assoc/bumped/refoisted.eld: New file.
* test/lisp/erc/resources/base/assoc/bumped/renicked.eld: New file.
* test/lisp/erc/resources/base/assoc/multi-net/barnet.eld: New file.
* test/lisp/erc/resources/base/assoc/multi-net/foonet.eld: New file.
* test/lisp/erc/resources/base/assoc/reconplay/again.eld: New file.
* test/lisp/erc/resources/base/assoc/reconplay/foonet.eld: New file.
* test/lisp/erc/resources/base/assoc/samenet/chester.eld: New file.
* test/lisp/erc/resources/base/assoc/samenet/tester.eld: New file.
* test/lisp/erc/resources/base/assoc/samenet/tester2.eld: New file.
* test/lisp/erc/resources/base/channel-buffer-revival/foonet.eld: New file.
* test/lisp/erc/resources/base/flood/soju.eld: New file.
* test/lisp/erc/resources/base/gapless-connect/barnet.eld: New file.
* test/lisp/erc/resources/base/gapless-connect/foonet.eld: New file.
* test/lisp/erc/resources/base/gapless-connect/pass-stub.eld: New file.
* test/lisp/erc/resources/base/netid/bouncer/barnet-again.eld: New file.
* test/lisp/erc/resources/base/netid/bouncer/barnet-drop.eld: New file.
* test/lisp/erc/resources/base/netid/bouncer/barnet.eld: New file.
* test/lisp/erc/resources/base/netid/bouncer/foonet-again.eld: New file.
* test/lisp/erc/resources/base/netid/bouncer/foonet-drop.eld: New file.
* test/lisp/erc/resources/base/netid/bouncer/foonet.eld: New file.
* test/lisp/erc/resources/base/netid/bouncer/stub-again.eld: New file.
* test/lisp/erc/resources/base/netid/samenet/chester.eld: New file.
* test/lisp/erc/resources/base/netid/samenet/tester.eld: New file.
* test/lisp/erc/resources/base/reconnect/aborted-dupe.eld: New file.
* test/lisp/erc/resources/base/reconnect/aborted.eld: New file.
* test/lisp/erc/resources/base/reconnect/options-again.eld: New file.
* test/lisp/erc/resources/base/reconnect/options.eld: New file.
* test/lisp/erc/resources/base/reconnect/timer-last.eld: New file.
* test/lisp/erc/resources/base/reconnect/timer.eld: New file.
* test/lisp/erc/resources/base/renick/queries/bouncer-barnet.eld: New file.
* test/lisp/erc/resources/base/renick/queries/bouncer-foonet.eld: New file.
* test/lisp/erc/resources/base/renick/queries/solo.eld: New file.
* test/lisp/erc/resources/base/renick/self/auto.eld: New file.
* test/lisp/erc/resources/base/renick/self/manual.eld: New file.
* test/lisp/erc/resources/base/renick/self/qual-chester.eld: New file.
* test/lisp/erc/resources/base/renick/self/qual-tester.eld: New file.
* test/lisp/erc/resources/base/reuse-buffers/server/barnet.eld: New file.
* test/lisp/erc/resources/base/reuse-buffers/server/foonet.eld: New file.
* test/lisp/erc/resources/base/upstream-reconnect/soju-barnet.eld: New file.
* test/lisp/erc/resources/base/upstream-reconnect/soju-foonet.eld: New file.
* test/lisp/erc/resources/base/upstream-reconnect/znc-barnet.eld: New file.
* test/lisp/erc/resources/base/upstream-reconnect/znc-foonet.eld: New file.
* test/lisp/erc/resources/erc-scenarios-common.el: New file.
* test/lisp/erc/resources/networks/announced-missing/foonet.eld: New file.
* test/lisp/erc/resources/services/password/libera.eld: New file.

Add test cases for locking down fundamental client behavior, much of
it involving the relationship between buffers and connections.  Also
add accompanying resources subdir containing canned dialog scripts and
common code needed by various tests.  For test cases demoing the
problematic behavior originally described in the initial report, see
update #4 on the bug tracker thread for bug#48598.  Most reside in a
file named test/lisp/erc/erc-scenarios-48598.el introduced by the
patch "Add user-oriented test scenarios for ERC".