master 9120d7a32ea 02/12: Honor nil values in erc--restore-initialize-priors

[F. Jason Park]

branch: master
commit 9120d7a32ea4906d7c9460add31d37c3ca38931e
Author: F. Jason Park <jp@neverwas.me>
Commit: F. Jason Park <jp@neverwas.me>

    Honor nil values in erc--restore-initialize-priors
    
    * lisp/erc/erc.el (erc--restore-initialize-priors): Don't produce
    invalid "empty" `setq' form when parameter VARS contains defaults that
    initialize to nil.  This function is mainly used by local modules,
    which were first made usable in ERC 5.5 (bug#57955).
    * test/lisp/erc/erc-tests.el (erc--restore-initialize-priors): Fix
    expected expansion, which is now slightly leaner.  (Bug#60936)
---
 lisp/erc/erc.el            | 17 ++++++++---------
 test/lisp/erc/erc-tests.el | 17 +++++++----------
 2 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index fb236f1f189..16651b41eef 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -1366,16 +1366,15 @@ buffer during local-module setup and `erc-mode-hook' 
activation.")
 (defmacro erc--restore-initialize-priors (mode &rest vars)
   "Restore local VARS for MODE from a previous session."
   (declare (indent 1))
-  (let ((existing (make-symbol "existing"))
+  (let ((priors (make-symbol "priors"))
+        (initp (make-symbol "initp"))
         ;;
-        restore initialize)
-    (while-let ((k (pop vars)) (v (pop vars)))
-      (push `(,k (alist-get ',k ,existing)) restore)
-      (push `(,k ,v) initialize))
-    `(if-let* ((,existing (or erc--server-reconnecting erc--target-priors))
-               ((alist-get ',mode ,existing)))
-         (setq ,@(mapcan #'identity (nreverse restore)))
-       (setq ,@(mapcan #'identity (nreverse initialize))))))
+        forms)
+    (while-let ((k (pop vars)))
+      (push `(,k (if ,initp (alist-get ',k ,priors) ,(pop vars))) forms))
+    `(let* ((,priors (or erc--server-reconnecting erc--target-priors))
+            (,initp (and ,priors (alist-get ',mode ,priors))))
+       (setq ,@(mapcan #'identity (nreverse forms))))))
 
 (defun erc--target-from-string (string)
   "Construct an `erc--target' variant from STRING."
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index 8a68eca6196..64b503832f3 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -796,18 +796,15 @@
       (should (erc--valid-local-channel-p "&local")))))
 
 (ert-deftest erc--restore-initialize-priors ()
-  ;; This `pcase' expands to 100+k.  Guess we could do something like
-  ;; (and `(,_ ((,e . ,_) . ,_) . ,_) v) first and then return a
-  ;; (equal `(if-let* ((,e ...)...)...) v) to cut it down to < 1k.
   (should (pcase (macroexpand-1 '(erc--restore-initialize-priors erc-my-mode
                                    foo (ignore 1 2 3)
-                                   bar #'spam))
-            (`(if-let* ((,e (or erc--server-reconnecting erc--target-priors))
-                        ((alist-get 'erc-my-mode ,e)))
-                  (setq foo (alist-get 'foo ,e)
-                        bar (alist-get 'bar ,e))
-                (setq foo (ignore 1 2 3)
-                      bar #'spam))
+                                   bar #'spam
+                                   baz nil))
+            (`(let* ((,p (or erc--server-reconnecting erc--target-priors))
+                     (,q (and ,p (alist-get 'erc-my-mode ,p))))
+                (setq foo (if ,q (alist-get 'foo ,p) (ignore 1 2 3))
+                      bar (if ,q (alist-get 'bar ,p) #'spam)
+                      baz (if ,q (alist-get 'baz ,p) nil)))
              t))))
 
 (ert-deftest erc--target-from-string ()