Don't insert prompt input before markers in ERC

* etc/ERC-NEWS: Update entry in 5.6 section announcing a persistent
prompt.
* lisp/erc/erc-dcc.el (erc-dcc-chat-setup): Use helper
`erc--initialize-markers' to set up prompt.
* lisp/erc/erc.el (erc--initialize-markers): Change
`erc-insert-marker' type to t.  Do this to spare modules that want to
remember the current message location from resorting to workarounds,
like leaving a marker one char before the end of a message, which is
not foolproof.
(erc--refresh-prompt): Temporarily change type of `erc-insert-marker'
when inserting prompt.
(erc-display-line-1): Insert incoming message normally instead of
forcing before markers, thus respecting markers left by third parties.
Strictly speaking, this is a breaking change.
(erc-display-msg): Insert normally instead of calling
`insert-before-markers', which was a regression introduced by 05f6fdb9
"Preserve ERC prompt and its bounding markers".
* test/lisp/erc/erc-dcc-tests.el
(erc-dcc-tests--dcc-handle-ctcp-send,
erc-dcc-tests--erc-dcc-do-GET-command): Use helper to initialize
prompt and markers.
* test/lisp/erc/erc-networks-tests.el
(erc-networks--ensure-announced,
erc-networks--rename-server-buffer--existing--reuse,
erc-networks--rename-server-buffer--existing--noreuse,
erc-networks--rename-server-buffer--reconnecting,
erc-networks--rename-server-buffer--id,
erc-networks--rename-server-buffer--existing--live,
erc-networks--rename-server-buffer--local-match,
erc-networks--rename-server-buffer--local-nomatch): Use helper to
initialize prompt and bounding markers.
* test/lisp/erc/erc-stamp-tests.el (erc-stamp-tests--insert-right):
Use `erc--initialize-markers' for setting up prompt.
* test/lisp/erc/erc-tests.el (erc--refresh-prompt): Adjust assertions
for expected prompt content.  (Bug#60936)

4 files changed, 39 insertions, 49 deletions

diff --git a/test/lisp/erc/erc-dcc-tests.el b/test/lisp/erc/erc-dcc-tests.el
index 7fb5f82e784..f02ddf228a2 100644
--- a/test/lisp/erc/erc-dcc-tests.el
+++ b/test/lisp/erc/erc-dcc-tests.el
@@ -57,11 +57,8 @@
       (erc-mode)
       (setq erc-server-process
             (start-process "fake" (current-buffer) "sleep" "10")
-            erc-input-marker (make-marker)
-            erc-insert-marker (make-marker)
             erc-server-current-nick "dummy")
-      (erc-display-prompt)
-      (set-marker erc-insert-marker (pos-bol))
+      (erc--initialize-markers (point) nil)
       (set-process-query-on-exit-flag erc-server-process nil)
       (should-not erc-dcc-list)
       (erc-ctcp-query-DCC erc-server-process
@@ -121,17 +118,14 @@
            calls)
       (erc-mode)
       (setq erc-server-process proc
-            erc-input-marker (make-marker)
-            erc-insert-marker (make-marker)
             erc-server-current-nick "dummy")
+      (erc--initialize-markers (point) nil)
       (set-process-query-on-exit-flag proc nil)
       (cl-letf (((symbol-function 'read-file-name)
                  (lambda (&rest _) file))
                 ((symbol-function 'erc-dcc-get-file)
                  (lambda (&rest r) (push r calls))))
         (goto-char (point-max))
-        (set-marker erc-insert-marker (point-max))
-        (erc-display-prompt)
 
         (ert-info ("No turbo")
           (should-not (plist-member elt :turbo))
diff --git a/test/lisp/erc/erc-networks-tests.el b/test/lisp/erc/erc-networks-tests.el
index b9d216f217b..f0fcbbc81c6 100644
--- a/test/lisp/erc/erc-networks-tests.el
+++ b/test/lisp/erc/erc-networks-tests.el
@@ -1233,10 +1233,7 @@
                    :contents "MOTD File is missing")))
 
       (erc-mode) ; boilerplate displayable start (needs `erc-server-process')
-      (insert "\n\n")
-      (setq erc-input-marker (make-marker) erc-insert-marker (make-marker))
-      (set-marker erc-insert-marker (point-max))
-      (erc-display-prompt) ; boilerplate displayable end
+      (erc--initialize-markers (point) nil)
 
       (erc-networks--ensure-announced erc-server-process parsed)
       (goto-char (point-min))
@@ -1277,9 +1274,9 @@
     (with-current-buffer old-buf
       (erc-mode)
       (insert "*** Old buf")
+      (erc--initialize-markers (point) nil)
       (setq erc-network 'FooNet
             erc-server-current-nick "tester"
-            erc-insert-marker (set-marker (make-marker) (point-max))
             erc-server-process old-proc
             erc-networks--id (erc-networks--id-create nil)))
 
@@ -1328,10 +1325,10 @@
            erc-reuse-buffers)
       (with-current-buffer old-buf
         (erc-mode)
+        (erc--initialize-markers (point) nil)
         (insert "*** Old buf")
         (setq erc-network 'FooNet
               erc-server-current-nick "tester"
-              erc-insert-marker (set-marker (make-marker) (point-max))
               erc-server-process old-proc
               erc-networks--id (erc-networks--id-create nil)))
       (with-current-buffer (get-buffer-create "#chan")
@@ -1377,10 +1374,10 @@
 
     (with-current-buffer old-buf
       (erc-mode)
+      (erc--initialize-markers (point) nil)
       (insert "*** Old buf")
       (setq erc-network 'FooNet
             erc-server-current-nick "tester"
-            erc-insert-marker (set-marker (make-marker) (point-max))
             erc-server-process old-proc
             erc-networks--id (erc-networks--id-create nil)))
 
@@ -1415,10 +1412,10 @@
 
     (with-current-buffer old-buf
       (erc-mode)
+      (erc--initialize-markers (point) nil)
       (insert "*** Old buf")
       (setq erc-network 'FooNet
             erc-networks--id (erc-networks--id-create 'MySession)
-            erc-insert-marker (set-marker (make-marker) (point-max))
             erc-server-process old-proc))
 
     (with-current-buffer (get-buffer-create "#chan")
@@ -1454,10 +1451,10 @@
 
     (with-current-buffer old-buf
       (erc-mode)
+      (erc--initialize-markers (point) nil)
       (insert "*** Old buf")
       (setq erc-network 'FooNet
             erc-server-current-nick "tester"
-            erc-insert-marker (set-marker (make-marker) (point-max))
             erc-server-process old-proc
             erc-networks--id (erc-networks--id-create nil))
       (should (erc-server-process-alive)))
@@ -1473,15 +1470,12 @@
     (ert-info ("New buffer rejected, abandoned, not killed")
       (with-current-buffer (get-buffer-create "irc.foonet.org")
         (erc-mode)
+        (erc--initialize-markers (point) nil)
         (setq erc-network 'FooNet
               erc-server-current-nick "tester"
-              erc-insert-marker (make-marker)
-              erc-input-marker (make-marker)
               erc-server-process (erc-networks-tests--create-live-proc)
               erc-networks--id (erc-networks--id-create nil))
         (set-process-sentinel erc-server-process #'ignore)
-        (erc-display-prompt nil (point-max))
-        (set-marker erc-insert-marker (pos-bol))
         (erc-display-message nil 'notice (current-buffer) "notice")
         (with-silent-modifications
           (should-not (erc-networks--rename-server-buffer erc-server-process)))
@@ -1514,10 +1508,10 @@
     (with-current-buffer old-buf
       (erc-mode)
       (insert "*** Old buf")
+      (erc--initialize-markers (point) nil)
       (setq erc-network 'FooNet
             erc-server-current-nick "tester"
             erc-server-announced-name "us-east.foonet.org"
-            erc-insert-marker (set-marker (make-marker) (point-max))
             erc-server-process old-proc
             erc--isupport-params (make-hash-table)
             erc-networks--id (erc-networks--id-create nil))
@@ -1566,10 +1560,10 @@
     (with-current-buffer old-buf
       (erc-mode)
       (insert "*** Old buf")
+      (erc--initialize-markers (point) nil)
       (setq erc-network 'FooNet
             erc-server-current-nick "tester"
             erc-server-announced-name "us-west.foonet.org"
-            erc-insert-marker (set-marker (make-marker) (point-max))
             erc-server-process old-proc
             erc--isupport-params (make-hash-table)
             erc-networks--id (erc-networks--id-create nil))
diff --git a/test/lisp/erc/erc-stamp-tests.el b/test/lisp/erc/erc-stamp-tests.el
index 01e71e348e0..6da7ed4503d 100644
--- a/test/lisp/erc/erc-stamp-tests.el
+++ b/test/lisp/erc/erc-stamp-tests.el
@@ -43,13 +43,10 @@
     (with-current-buffer (get-buffer-create "*erc-stamp-tests--insert-right*")
       (erc-mode)
       (erc-munge-invisibility-spec)
+      (erc--initialize-markers (point) nil)
       (setq erc-server-process (start-process "p" (current-buffer)
-                                              "sleep" "1")
-            erc-input-marker (make-marker)
-            erc-insert-marker (make-marker))
+                                              "sleep" "1"))
       (set-process-query-on-exit-flag erc-server-process nil)
-      (set-marker erc-insert-marker (point-max))
-      (erc-display-prompt)
 
       (funcall test)
 
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index 7d1e20132e1..f3489a16386 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -294,16 +294,19 @@
         (set-process-query-on-exit-flag erc-server-process nil)
         ;; Incoming message redraws prompt
         (erc-display-message nil 'notice nil "Welcome")
+        (should (looking-at-p (rx "*** Welcome")))
+        (forward-line)
         (should (looking-at-p "ServNet 4>"))
         ;; Say something
-        (save-excursion (goto-char erc-input-marker)
-                        (insert "Howdy")
-                        (erc-send-current-line)
-                        (forward-line -1)
+        (goto-char erc-input-marker)
+        (insert "Howdy")
+        (erc-send-current-line)
+        (save-excursion (forward-line -1)
                         (should (looking-at "No target"))
                         (forward-line -1)
                         (should (looking-at "<tester> Howdy")))
-        (should (looking-at-p "ServNet 6>"))
+        (should (looking-back "ServNet 6> "))
+        (should (= erc-input-marker (point)))
         ;; Space after prompt is unpropertized
         (should (get-text-property (1- erc-input-marker) 'erc-prompt))
         (should-not (get-text-property erc-input-marker 'erc-prompt))
@@ -317,6 +320,7 @@
         (erc-tests--send-prep)
         (goto-char erc-insert-marker)
         (should (looking-at-p "#chan 9>"))
+        (goto-char erc-input-marker)
         (setq erc-server-process (buffer-local-value 'erc-server-process
                                                      (get-buffer "ServNet"))
               erc-networks--id (erc-with-server-buffer erc-networks--id)
@@ -328,18 +332,18 @@
         (erc-update-current-channel-member "tester" "tester")
         (erc-display-message nil nil (current-buffer)
                              (erc-format-privmessage "alice" "Hi" nil t))
-        (should (looking-at-p "#chan@ServNet 10>"))
-        (save-excursion (goto-char erc-input-marker)
-                        (insert "Howdy")
-                        (erc-send-current-line)
-                        (forward-line -1)
+        (should (looking-back "#chan@ServNet 10> "))
+        (goto-char erc-input-marker)
+        (insert "Howdy")
+        (erc-send-current-line)
+        (save-excursion (forward-line -1)
                         (should (looking-at "<tester> Howdy")))
-        (should (looking-at-p "#chan@ServNet 11>"))
-        (save-excursion (goto-char erc-input-marker)
-                        (insert "/query bob")
-                        (erc-send-current-line))
+        (should (looking-back "#chan@ServNet 11> "))
+        (should (= (point) erc-input-marker))
+        (insert "/query bob")
+        (erc-send-current-line)
         ;; Query does not redraw (nor /help, only message input)
-        (should (looking-at-p "#chan@ServNet 11>"))
+        (should (looking-back "#chan@ServNet 11> "))
         ;; No sign of old prompts
         (save-excursion
           (goto-char (point-min))
@@ -349,15 +353,16 @@
       (with-current-buffer (get-buffer "bob")
         (goto-char erc-insert-marker)
         (should (looking-at-p "bob@ServNet 14>"))
+        (goto-char erc-input-marker)
         (erc-display-message nil nil (current-buffer)
                              (erc-format-privmessage "bob" "Hi" nil t))
-        (should (looking-at-p "bob@ServNet 15>"))
-        (save-excursion (goto-char erc-input-marker)
-                        (insert "Howdy")
-                        (erc-send-current-line)
-                        (forward-line -1)
+        (should (looking-back "bob@ServNet 15> "))
+        (goto-char erc-input-marker)
+        (insert "Howdy")
+        (erc-send-current-line)
+        (save-excursion (forward-line -1)
                         (should (looking-at "<tester> Howdy")))
-        (should (looking-at-p "bob@ServNet 16>"))
+        (should (looking-back "bob@ServNet 16> "))
         ;; No sign of old prompts
         (save-excursion
           (goto-char (point-min))