Deprecate erc-button-nickname-callback-function

* lisp/erc/erc-button.el (erc-button-nickname-callback-function):
Deprecate this function-valued variable, first introduced in ERC 5.6
and Emacs 30, to dissuade consumers of the old `erc-button-alist'
nickname interface from meddling with the on-click callback of
buttonized nicks.  If necessary, third parties can instead add their
own propertizing logic in something like `erc-insert-modify-hook'.
Also change default callback to a wrapper that discards all but the
first arg.  This effectively declares that `erc-data' values for
nicknames may contain more than one element in the near future.
(erc-button--perform-nick-popup): New default nick-button callback
function wrapping `erc-nick-popup' in order to adapt it to the
`erc-button-nickname-callback-function' interface.  (Bug#60933)

diff --git a/lisp/erc/erc-button.el b/lisp/erc/erc-button.el
index 89a6cd131c06a9cf45c52c7734e195ec207aeec4..bfaf4fa821a852b3211afeaec1cf513153fbc144 100644 (file)
--- a/lisp/erc/erc-button.el
+++ b/lisp/erc/erc-button.el
@@ -279,8 +279,13 @@ themselves."
          " entries are deprecated. Either use a variable or a function"
          " that conditionally calls `erc-button-add-button'.")))))
 
-(defvar erc-button-nickname-callback-function #'erc-nick-popup
-  "Escape hatch for those needing a different nickname callback.")
+(defvar erc-button-nickname-callback-function #'erc-button--perform-nick-popup
+  "Escape hatch for users needing a non-standard nick-button callback.
+Value should be a function accepting a NICK and any number of
+trailing arguments that are as yet unspecified.  Runs when
+clicking \\`<mouse-1>' or hitting \\`RET' atop a nickname button.")
+(make-obsolete-variable 'erc-button-nickname-callback-function
+                        "default provides essential functionality" "30.1")
 
 (defun erc-button-add-buttons ()
   "Find external references in the current buffer and make buttons of them.
@@ -745,6 +750,10 @@ In server buffers, also prompt for a channel."
           (funcall code nick)
         (eval code `((nick . ,nick)))))))
 
+(defun erc-button--perform-nick-popup (nick &rest _)
+  "Call `erc-nick-popup' with NICK."
+  (erc-nick-popup nick))
+
 ;;; Callback functions
 (defun erc-button-describe-symbol (symbol-name)
   "Describe SYMBOL-NAME.