Improve multi-window erc-keep-place-indicator-mode

* lisp/erc/erc-goodies.el (erc-keep-place-indicator-follow): Describe
condition causing an indicator update.
(erc--keep-place-indicator-on-window-configuration-change,
erc--keep-place-indicator-on-window-buffer-change): Rename former to
latter, add required WINDOW parameter, and don't move indicator if
buffer appears in multiple windows.  Also, don't bother checking
whether either buffer is a mini because the manual says window change
functions don't run for minibuffer replacements.
(erc--keep-place-indicator-setup): Hook on
`window-buffer-change-functions' instead of
`window-configuration-change-hook'.
(erc-keep-place-mode, erc-keep-place-disable): Remove member from
`window-buffer-change-functions' instead of
`window-configuration-change-hook'.
(erc-keep-place): Use `visible' FRAME arg of `get-buffer-window'.
Don't twiddle `window-prev-buffers' when
`erc-keep-place-indicator-mode' is non-nil.  This feature was
originally introduced by bug#59943.
* test/lisp/erc/erc-goodies-tests.el
(erc-goodies-tests--assert-kp-indicator-on,
erc-goodies-tests--assert-kp-indicator-off): Update hook name.
* test/lisp/erc/erc-scenarios-keep-place-indicator.el: New file.
* test/lisp/erc/resources/keep-place/follow.eld: New file.

1 files changed, 73 insertions, 0 deletions

diff --git a/test/lisp/erc/resources/keep-place/follow.eld b/test/lisp/erc/resources/keep-place/follow.eld
new file mode 100644
index 00000000000..e857c17175d
--- /dev/null
+++ b/test/lisp/erc/resources/keep-place/follow.eld
@@ -0,0 +1,73 @@
+;; -*- mode: lisp-data; -*-
+((nick 10 "NICK tester"))
+((user 10 "USER tester 0 * :tester")
+ (0.00 ":irc.foonet.org 001 tester :Welcome to the foonet IRC Network tester")
+ (0.01 ":irc.foonet.org 002 tester :Your host is irc.foonet.org, running version ergo-v2.11.1")
+ (0.01 ":irc.foonet.org 003 tester :This server was created Tue, 26 Dec 2023 08:36:35 UTC")
+ (0.01 ":irc.foonet.org 004 tester irc.foonet.org ergo-v2.11.1 BERTZios CEIMRUabefhiklmnoqstuv Iabefhkloqv")
+ (0.00 ":irc.foonet.org 005 tester AWAYLEN=390 BOT=B CASEMAPPING=ascii CHANLIMIT=#:100 CHANMODES=Ibe,k,fl,CEMRUimnstu CHANNELLEN=64 CHANTYPES=# CHATHISTORY=1000 ELIST=U EXCEPTS EXTBAN=,m FORWARD=f INVEX :are supported by this server")
+ (0.01 ":irc.foonet.org 005 tester KICKLEN=390 MAXLIST=beI:60 MAXTARGETS=4 MODES MONITOR=100 NETWORK=foonet NICKLEN=32 PREFIX=(qaohv)~&@%+ STATUSMSG=~&@%+ TARGMAX=NAMES:1,LIST:1,KICK:,WHOIS:1,USERHOST:10,PRIVMSG:4,TAGMSG:4,NOTICE:4,MONITOR:100 TOPICLEN=390 UTF8ONLY WHOX :are supported by this server")
+ (0.01 ":irc.foonet.org 005 tester draft/CHATHISTORY=1000 :are supported by this server")
+ (0.01 ":irc.foonet.org 251 tester :There are 0 users and 4 invisible on 1 server(s)")
+ (0.01 ":irc.foonet.org 252 tester 0 :IRC Operators online")
+ (0.00 ":irc.foonet.org 253 tester 0 :unregistered connections")
+ (0.00 ":irc.foonet.org 254 tester 2 :channels formed")
+ (0.00 ":irc.foonet.org 255 tester :I have 4 clients and 0 servers")
+ (0.00 ":irc.foonet.org 265 tester 4 4 :Current local users 4, max 4")
+ (0.00 ":irc.foonet.org 266 tester 4 4 :Current global users 4, max 4")
+ (0.03 ":irc.foonet.org 422 tester :MOTD File is missing")
+ (0.01 ":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."))
+
+((mode 10 "MODE tester +i"))
+
+((join 10 "JOIN #chan")
+ (0.01 ":irc.foonet.org 221 tester +i")
+ (0.01 ":tester!~u@p64eqfwvvbxrk.irc JOIN #chan")
+ (0.03 ":irc.foonet.org 353 tester = #chan :@fsbot bob alice tester")
+ (0.01 ":irc.foonet.org 366 tester #chan :End of NAMES list")
+ (0.00 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :tester, welcome!")
+ (0.01 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :tester, welcome!"))
+
+((join 10 "JOIN #spam")
+ (0.00 ":tester!~u@p64eqfwvvbxrk.irc JOIN #spam")
+ (0.06 ":irc.foonet.org 353 tester = #spam :@fsbot bob alice tester")
+ (0.01 ":irc.foonet.org 366 tester #spam :End of NAMES list")
+ (0.03 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #spam :tester, welcome!")
+ (0.01 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #spam :tester, welcome!"))
+
+((mode 10 "MODE #chan")
+ (0.00 ":irc.foonet.org 324 tester #chan +Cnt")
+ (0.02 ":irc.foonet.org 329 tester #chan 1703579802")
+ (0.02 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :bob: Madam, my lord is gone, for ever gone.")
+ (0.10 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :The kinder we, to give them thanks for nothing."))
+
+((mode 10 "MODE #spam")
+ (0.00 ":irc.foonet.org 324 tester #spam +Cnt")
+ (0.02 ":irc.foonet.org 329 tester #spam 1703579805")
+ (0.02 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :Most manifest, and not denied by himself.")
+ (0.02 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :alice: To bed, to bed: there's knocking at the gate. Come, come, come, come, give me your hand. What's done cannot be undone.")
+ (0.02 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :bob: And what I spake, I spake it to my face.")
+ (0.08 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :alice: Since you can cog, I'll play no more with you.")
+ (0.06 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :bob: The little casket bring me hither.")
+ (0.01 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :alice: Not to-night, good Iago: I have very poor and unhappy brains for drinking: I could well wish courtesy would invent some other custom of entertainment.")
+ (0.02 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :Yes, faith will I, Fridays and Saturdays and all."))
+
+((privmsg 10 "PRIVMSG #spam :one")
+ (0.03 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :bob: This is the first truth that e'er thine own tongue was guilty of.")
+ (0.02 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :alice: Drown the lamenting fool in sea-salt tears.")
+
+ ;; Insert some lines ^ before rendezvous, so #chan can update scrolltobottom.
+ (0.01 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #spam :Ay, the heads of the maids, or their maidenheads; take it in what sense thou wilt.")
+
+ (0.05 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :alice: And work confusion on his enemies.")
+ (0.06 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :bob: Truly, she must be given, or the marriage is not lawful."))
+
+((privmsg 10 "PRIVMSG #spam :two")
+ (0.02 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :To be whipped; and yet a better love than my master.")
+ (0.06 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :And duty in his service perishing.")
+
+ ;; Second check point.
+ (0.01 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #spam :Cause they take vengeance of such kind of men.")
+
+ (0.03 ":bob!~u@2q6ysndq32az6.irc PRIVMSG #chan :alice: No egma, no riddle, no l'envoy; no salve in the mail, sir. O! sir, plantain, a plain plantain: no l'envoy, no l'envoy: no salve, sir, but a plantain.")
+ (0.03 ":alice!~u@2q6ysndq32az6.irc PRIVMSG #chan :Signior Iachimo will not from it. Pray, let us follow 'em."))