From c598169155621940e8842c2d53f835d6751d154f Mon Sep 17 00:00:00 2001
From: Joseph Ferano <joseph@ferano.io>
Date: Sat, 12 Sep 2026 14:54:53 +0700
Subject: [PATCH] Folding a frame is a display operation when there is nothing
 to ask

---
 emacs/flan-cnr.el        |  8 +++++++-
 emacs/test-flan-cider.el | 21 +++++++++++++++++----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/emacs/flan-cnr.el b/emacs/flan-cnr.el
index 67a6b57..0dfae9b 100644
--- a/emacs/flan-cnr.el
+++ b/emacs/flan-cnr.el
@@ -324,7 +324,13 @@ list already says it."
     ;; Fetched on first open and then kept: a frame's locals cannot change
     ;; while the program is stopped, and re-asking on every fold would put a
     ;; round trip behind a keystroke that looks like pure redrawing.
-    (when (memq i flan-cnr--open)
+    ;; Only when there is something to ask. The fixture tests render this
+    ;; buffer from a literal state with no socket behind it and no `flan-dev'
+    ;; loaded, and folding a frame must stay a display operation there — the
+    ;; renderer already draws a reason for a frame whose locals are nil, which
+    ;; is the same degradation every other section of this buffer uses.
+    (when (and (memq i flan-cnr--open)
+               (functionp flan-cnr-request-function))
       (let ((fr (nth i (plist-get flan-cnr--state :stack))))
         (when (and fr (not (plist-get fr :fetched)))
           (let ((answer (flan-cnr-locals i)))
diff --git a/emacs/test-flan-cider.el b/emacs/test-flan-cider.el
index 6c1177d..4ce93b0 100644
--- a/emacs/test-flan-cider.el
+++ b/emacs/test-flan-cider.el
@@ -409,8 +409,12 @@
     (goto-char (point-min))
     (search-forward " 1: > sim/step")
     (flan-cnr-toggle-frame)
-    (test-flan--check "a frame with no locals refuses, naming DWARF"
-                      (string-match-p "not available.*DWARF" (buffer-string)))
+    ;; DWARF stopped being the reason when the shadow stack landed: a frame
+    ;; with nothing nameable is one whose slots the compiler invented, or whose
+    ;; bindings had not run.
+    (test-flan--check "a frame with no locals refuses, with a reason"
+                      (string-match-p "not available.*no named locals"
+                                      (buffer-string)))
     (goto-char (point-min))
     (search-forward " 0: v sim/settle")
     (flan-cnr-toggle-frame)
@@ -472,7 +476,11 @@
 
 ;; The `layout' op, from this side: the condition's own name goes out as
 ;; `:type' and comes back as fields with no values. Two requests are made for
-;; one `C-c C-b' — `break' then `layout' — so the stub records both.
+;; one `C-c C-b' — `break', `layout', then `backtrace' — so the stub records
+;; all three. The assertions below look the `layout' request up by op rather
+;; than by position: this list grew once already when `backtrace' landed, and a
+;; positional assertion breaks every time the buffer learns to ask something
+;; new, which is not what it is testing.
 (let ((asked nil))
   (let ((flan-cnr-request-function
          (lambda (form)
@@ -487,7 +495,12 @@
       (test-flan--check "the condition's name is what `layout' is asked for"
                         (equal (plist-get (car (last asked)) :op) "break"))
       (test-flan--check "and it is sent back verbatim, qualified as it came"
-                        (equal (plist-get (car asked) :type) "sim/Missing"))
+                        (equal (plist-get
+                                (seq-find (lambda (f)
+                                            (equal (plist-get f :op) "layout"))
+                                          asked)
+                                :type)
+                               "sim/Missing"))
       (test-flan--check "the fields are drawn, named and typed"
                         (string-match-p ":path *string" text))
       ;; Shape and contents are two different questions, and only the first is