ERC: NickServ: Prompt for password last, overall simplifications (bug#46777)

When 'erc-prompt-for-nickserv-password' is non-nil, don't ignore the
other forms of identification.  Instead, process them first, and
prompt for the password last.  Separate concerns (determination of the
nick to use, of the password to use, and actual message sending).

Note that the user can be interactively prompted for a password on
reception of a NickServ request, as before (on
'erc-prompt-for-nickserv-password').

* lisp/erc/erc-services.el (erc-nickserv-identify): Make the password
argument optional (and don't prompt for it interactively).  Further,
now take the nick to use for identification (interactively, ask for
it, defaulting to the current one).  Move the actual message sending
into the new 'erc-nickserv-send-identify' function, and the password
prompting into 'erc-nickserv-get-password'.

(erc-nickserv-send-identify): New function containing the code for
sending the identify message to NickServ, given the nick and password.

(erc-nickserv-get-password): Try each password source in turn, in the
following order: 'erc-nickserv-passwords', auth-source (if
'erc-use-auth-source-for-nickserv-password' is non-nil), and in the
end prompt the user interactively (if
'erc-prompt-for-nickserv-password' is non-nil).  If one source returns
a string, the function returns it, or nil if the string is empty.

(erc-nickserv-call-identify-function): Declare obsolete, but retain
for backward compatibility.  Prefer invoking 'erc-nickserv-identify'
directly instead.

(erc-nickserv-identify-autodetect, erc-nickserv-identify-on-connect)
(erc-nickserv-identify-on-nick-change): Call 'erc-nickserv-identify'
directly ('erc-nickserv-call-identify-function' has been obsoleted).
For the last two functions, remove the redundant checks on the
NickServ identification flags (additionally, it is doubtful they have
any measurable impact on performance).

* etc/NEWS: Announce the change.

Co-authored-by: F. Jason Park <jp@neverwas.me>

1 files changed, 98 insertions, 70 deletions

diff --git a/lisp/erc/erc-services.el b/lisp/erc/erc-services.el
index 61006e0c028..adb3f521cdd 100644
--- a/lisp/erc/erc-services.el
+++ b/lisp/erc/erc-services.el
@@ -169,9 +169,8 @@ You can also use \\[erc-nickserv-identify-mode] to change modes."
 
 (defcustom erc-use-auth-source-for-nickserv-password nil
   "Query auth-source for a password when identifiying to NickServ.
-This option has an no effect if `erc-prompt-for-nickserv-password'
-is non-nil, and passwords from `erc-nickserv-passwords' take
-precedence."
+Passwords from `erc-nickserv-passwords' take precedence.  See
+function `erc-nickserv-get-password'."
   :version "28.1"
   :type 'boolean)
 
@@ -405,85 +404,114 @@ password for this nickname, otherwise try to send it automatically."
 		 identify-regex
 		 (string-match identify-regex msg))
 	(erc-log "NickServ IDENTIFY request detected")
-	(erc-nickserv-call-identify-function nick)
+        (erc-nickserv-identify nil nick)
 	nil))))
 
 (defun erc-nickserv-identify-on-connect (_server nick)
   "Identify to Nickserv after the connection to the server is established."
-  (unless (or (and (null erc-nickserv-passwords)
-                   (null erc-prompt-for-nickserv-password)
-                   (null erc-use-auth-source-for-nickserv-password))
-              (and (eq erc-nickserv-identify-mode 'both)
-                   (erc-nickserv-alist-regexp (erc-network))))
-    (erc-nickserv-call-identify-function nick)))
+  (unless (and (eq erc-nickserv-identify-mode 'both)
+               (erc-nickserv-alist-regexp (erc-network)))
+    (erc-nickserv-identify nil nick)))
 
 (defun erc-nickserv-identify-on-nick-change (nick _old-nick)
   "Identify to Nickserv whenever your nick changes."
-  (unless (or (and (null erc-nickserv-passwords)
-                   (null erc-prompt-for-nickserv-password)
-                   (null erc-use-auth-source-for-nickserv-password))
-              (and (eq erc-nickserv-identify-mode 'both)
-                   (erc-nickserv-alist-regexp (erc-network))))
-    (erc-nickserv-call-identify-function nick)))
-
-(defun erc-nickserv-get-password (nickname)
-  "Return the password for NICKNAME from configured sources.
-
-It uses `erc-nickserv-passwords' and additionally auth-source
-when `erc-use-auth-source-for-nickserv-password' is not nil."
-  (or
-   (when erc-nickserv-passwords
-     (cdr (assoc nickname
-                 (nth 1 (assoc (erc-network)
-                               erc-nickserv-passwords)))))
-   (when erc-use-auth-source-for-nickserv-password
-     (let* ((secret (nth 0 (auth-source-search
-                            :max 1 :require '(:secret)
-                            :host (erc-with-server-buffer erc-session-server)
-                            :port (format ; ensure we have a string
-                                   "%s" (erc-with-server-buffer erc-session-port))
-                            :user nickname))))
-       (when secret
-         (let ((passwd (plist-get secret :secret)))
-           (if (functionp passwd) (funcall passwd) passwd)))))))
-
-(defun erc-nickserv-call-identify-function (nickname)
-  "Call `erc-nickserv-identify'.
-Either call it interactively or run it with NICKNAME's password,
-depending on the value of `erc-prompt-for-nickserv-password'."
-  (if erc-prompt-for-nickserv-password
-      (call-interactively 'erc-nickserv-identify)
-    (erc-nickserv-identify (erc-nickserv-get-password nickname))))
+  (unless (and (eq erc-nickserv-identify-mode 'both)
+               (erc-nickserv-alist-regexp (erc-network)))
+    (erc-nickserv-identify nil nick)))
+
+(defun erc-nickserv-get-password (nick)
+  "Return the password for NICK from configured sources.
+First, a password for NICK is looked up in
+`erc-nickserv-passwords'.  Then, it is looked up in auth-source
+if `erc-use-auth-source-for-nickserv-password' is not nil.
+Finally, interactively prompt the user, if
+`erc-prompt-for-nickserv-password' is true.
+
+As soon as some source returns a password, the sequence of
+lookups stops and this function returns it (or returns nil if it
+is empty).  Otherwise, no corresponding password was found, and
+it returns nil."
+  (let (network server port)
+    ;; Fill in local vars, switching to the server buffer once only
+    (erc-with-server-buffer
+     (setq network erc-network
+           server erc-session-server
+           port erc-session-port))
+    (let ((ret
+           (or
+            (when erc-nickserv-passwords
+              (cdr (assoc nick
+                          (cl-second (assoc network
+                                            erc-nickserv-passwords)))))
+            (when erc-use-auth-source-for-nickserv-password
+              (let ((secret (cl-first (auth-source-search
+                                       :max 1 :require '(:secret)
+                                       :host server
+                                       ;; Ensure a string for :port
+                                       :port (format "%s" port)
+                                       :user nick))))
+                (when secret
+                  (let ((passwd (plist-get secret :secret)))
+                    (if (functionp passwd) (funcall passwd) passwd)))))
+            (when erc-prompt-for-nickserv-password
+              (read-passwd
+               (format "NickServ password for %s on %s (RET to cancel): "
+                       nick network))))))
+      (when (and ret (not (string= ret "")))
+        ret))))
 
 (defvar erc-auto-discard-away)
 
-;;;###autoload
-(defun erc-nickserv-identify (password)
+(defun erc-nickserv-send-identify (nick password)
   "Send an \"identify <PASSWORD>\" message to NickServ.
-When called interactively, read the password using `read-passwd'."
+Returns t if the message could be sent, nil otherwise."
+  (let* ((erc-auto-discard-away nil)
+         (network (erc-network))
+         (nickserv-info (assoc network erc-nickserv-alist))
+         (nickserv (or (erc-nickserv-alist-nickserv nil nickserv-info)
+                       "NickServ"))
+         (identify-word (or (erc-nickserv-alist-ident-keyword
+                             nil nickserv-info)
+                            "IDENTIFY"))
+         (nick (if (erc-nickserv-alist-use-nick-p nil nickserv-info)
+                   (concat nick " ")
+                 ""))
+         (msgtype (or (erc-nickserv-alist-ident-command nil nickserv-info)
+                      "PRIVMSG")))
+    (erc-message msgtype
+                 (concat nickserv " " identify-word " " nick password))))
+
+(defun erc-nickserv-call-identify-function (nickname)
+  "Call `erc-nickserv-identify' with NICKNAME."
+  (declare (obsolete erc-nickserv-identify "28.1"))
+  (erc-nickserv-identify nil nickname))
+
+;;;###autoload
+(defun erc-nickserv-identify (&optional password nick)
+  "Identify to NickServ immediately.
+Identification will either use NICK or the current nick if not
+provided, and some password obtained through
+`erc-nickserv-get-password' (which see).  If no password can be
+found, an error is reported trough `erc-error'.
+
+Interactively, the user will be prompted for NICK, an empty
+string meaning to default to the current nick.
+
+Returns t if the identify message could be sent, nil otherwise."
   (interactive
-   (list (read-passwd
-	  (format "NickServ password for %s on %s (RET to cancel): "
-		  (erc-current-nick)
-		  (or (and (erc-network)
-			   (symbol-name (erc-network)))
-		      "Unknown network")))))
-  (when (and password (not (string= "" password)))
-    (let* ((erc-auto-discard-away nil)
-	   (network (erc-network))
-	   (nickserv-info (assoc network erc-nickserv-alist))
-	   (nickserv (or (erc-nickserv-alist-nickserv nil nickserv-info)
-			 "NickServ"))
-	   (identify-word (or (erc-nickserv-alist-ident-keyword
-			       nil nickserv-info)
-			      "IDENTIFY"))
-	   (nick (if (erc-nickserv-alist-use-nick-p nil nickserv-info)
-		     (concat (erc-current-nick) " ")
-		   ""))
-	   (msgtype (or (erc-nickserv-alist-ident-command nil nickserv-info)
-			"PRIVMSG")))
-      (erc-message msgtype
-		   (concat nickserv " " identify-word " " nick password)))))
+   (list
+    nil
+    (read-from-minibuffer "Nickname: " nil nil nil
+                          'erc-nick-history-list (erc-current-nick))))
+  (unless (and nick (not (string= nick "")))
+    (setq nick (erc-current-nick)))
+  (unless password
+    (setq password (erc-nickserv-get-password nick)))
+  (if password
+      (erc-nickserv-send-identify nick password)
+    (erc-error "Cannot find a password for nickname %s"
+               nick)
+    nil))
 
 (provide 'erc-services)