Make edebug-step-in work on generic methods (Bug#22294)

* lisp/emacs-lisp/edebug.el (edebug-match-cl-generic-method-args):
New function to implement the edebug-form-spec property of
the symbol cl-generic-method-args.
(edebug-instrument-function): If the function is a generic
function, find and instrument all of its methods. Return a list
instead of a single symbol.
(edebug-instrument-callee): Now returns a list. Update docstring.
(edebug-step-in): Handle the list returned by edebug-instrument-callee.
* lisp/emacs-lisp/cl-generic.el (cl-defmethod): Use name and
cl-generic-method-args in its Edebug spec.
* lisp/emacs-lisp/eieio-compat.el (defmethod): Use name and
cl-generic-method-args in its Edebug spec.
* lisp/subr.el (method-files): New function.
* test/lisp/subr-tests.el (subr-tests--method-files--finds-methods)
(subr-tests--method-files--nonexistent-methods): New tests.

1 files changed, 24 insertions, 0 deletions

diff --git a/test/lisp/subr-tests.el b/test/lisp/subr-tests.el
index 0d243cc5d8c..8fa258d12ed 100644
--- a/test/lisp/subr-tests.el
+++ b/test/lisp/subr-tests.el
@@ -291,5 +291,29 @@ cf. Bug#25477."
   (should-error (eval '(dolist "foo") t)
                 :type 'wrong-type-argument))
 
+(require 'cl-generic)
+(cl-defgeneric subr-tests--generic (x))
+(cl-defmethod subr-tests--generic ((x string))
+  (message "%s is a string" x))
+(cl-defmethod subr-tests--generic ((x integer))
+  (message "%s is a number" x))
+(cl-defgeneric subr-tests--generic-without-methods (x y))
+(defvar subr-tests--this-file (or load-file-name buffer-file-name))
+
+(ert-deftest subr-tests--method-files--finds-methods ()
+  "`method-files' returns a list of files and methods for a generic function."
+  (let ((retval (method-files 'subr-tests--generic)))
+    (should (equal (length retval) 2))
+    (mapc (lambda (x)
+            (should (equal (car x) subr-tests--this-file))
+            (should (equal (cadr x) 'subr-tests--generic)))
+          retval)
+    (should-not (equal (nth 0 retval) (nth 1 retval)))))
+
+(ert-deftest subr-tests--method-files--nonexistent-methods ()
+  "`method-files' returns nil if asked to find a method which doesn't exist."
+  (should-not (method-files 'subr-tests--undefined-generic))
+  (should-not (method-files 'subr-tests--generic-without-methods)))
+
 (provide 'subr-tests)
 ;;; subr-tests.el ends here