Call PF correctly from pcase--edebug-match-pat-args

Also correct a doc string and insert commentary.  This fixes
bug#74052.

* lisp/emacs-lisp/edebug.el
(edebug--match-&-spec-op <&interpose>): Correct and complete
the doc string, which now says MUST call exactly once, and
documents the return values of FUN, PF and
edebug--match-&-spec-op.  Also remove an unneeded `(...)
construct.

* lisp/emacs-lisp/pcase.el (pcase--edebug-match-pat-args): Call
PF also for the main cases handled.

1 files changed, 11 insertions, 8 deletions

diff --git a/lisp/emacs-lisp/pcase.el b/lisp/emacs-lisp/pcase.el
index 898d460c144..9812621d50e 100644
--- a/lisp/emacs-lisp/pcase.el
+++ b/lisp/emacs-lisp/pcase.el
@@ -84,14 +84,17 @@
 (defun pcase--edebug-match-pat-args (head pf)
   ;; (cl-assert (null (cdr head)))
   (setq head (car head))
-  (or (alist-get head '((quote sexp)
-                        (or    &rest pcase-PAT)
-                        (and   &rest pcase-PAT)
-                        (guard form)
-                        (pred  &or ("not" pcase-FUN) pcase-FUN)
-                        (app   pcase-FUN pcase-PAT)))
-      (let ((me (pcase--get-macroexpander head)))
-        (funcall pf (and me (symbolp me) (edebug-get-spec me))))))
+  (let ((specs
+         (or
+          (alist-get head '((quote sexp)
+                            (or    &rest pcase-PAT)
+                            (and   &rest pcase-PAT)
+                            (guard form)
+                            (pred  &or ("not" pcase-FUN) pcase-FUN)
+                            (app   pcase-FUN pcase-PAT)))
+          (let ((me (pcase--get-macroexpander head)))
+            (and me (symbolp me) (edebug-get-spec me))))))
+    (funcall pf specs)))
 
 (defun pcase--get-macroexpander (s)
   "Return the macroexpander for pcase pattern head S, or nil."