bug#35737: xref--original-command

[Juri Linkov <juri@linkov.net>]

Remembering the command that created the *xref* buffer
will allow such customization to treat RET differently,
i.e. it makes sense for RET to quit the transient xref buffer
displayed momentarily while navigating code with xref-find-definitions,
whereas leaving the xref buffer visible while navigating matches
in the xref buffer created by e.g. project-find-regexp:

(define-key xref--button-map [(control ?m)]
  (lambda ()
    (interactive)
    (if (memq xref--original-command '(xref-find-definitions))
        (call-interactively 'xref-quit-and-goto-xref)
      (call-interactively 'xref-goto-xref))))

Better ideas?

diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
index bf999aeb0d..5c38cac164 100644
--- a/lisp/progmodes/xref.el
+++ b/lisp/progmodes/xref.el
@@ -477,6 +477,9 @@ xref--original-window-intent
 (defvar-local xref--original-window nil
   "The original window this xref buffer was created from.")
 
+(defvar-local xref--original-command nil
+  "The original command that created this xref buffer.")
+
 (defun xref--show-pos-in-buf (pos buf)
   "Goto and display position POS of buffer BUF in a window.
 Honor `xref--original-window-intent', run `xref-after-jump-hook'
@@ -777,7 +788,8 @@ xref--analyze
         (pop-to-buffer (current-buffer))
         (goto-char (point-min))
         (setq xref--original-window (assoc-default 'window alist)
-              xref--original-window-intent (assoc-default 'display-action alist))
+              xref--original-window-intent (assoc-default 'display-action alist)
+              xref--original-command this-command)
         (current-buffer)))))