fix(font-config): daemon emoji images and a re-runnable font list

emojify-display-style was computed once from env-gui-p inside the :defer'd :config block. In a daemon that block runs before any GUI frame exists, so the style latched to unicode and GUI frames never got image emoji. Recompute it per-frame from server-after-make-frame-hook, mirroring the emoji-fontset setup above.

cj/display-available-fonts called special-mode at the end, leaving the buffer read-only, so the second invocation errored on erase-buffer. Rewrite it under inhibit-read-only.

2 files changed, 74 insertions, 16 deletions

diff --git a/modules/font-config.el b/modules/font-config.el
index 3aa3d80f..e5afb361 100644
--- a/modules/font-config.el
+++ b/modules/font-config.el
@@ -210,6 +210,15 @@ the fontset repeatedly is harmless, so it can be called from
 ;; ---------------------------------- Emojify ----------------------------------
 ;; converts emoji identifiers into emojis; allows for easy emoji entry.
 
+(defvar emojify-display-style)          ;; emojify's, forward-declared for the helper
+
+(defun cj/set-emojify-display-style ()
+  "Set `emojify-display-style' to `image' on a graphical frame, else `unicode'.
+Image emoji only render on a GUI frame.  In daemon mode no GUI frame exists when
+emojify loads, so this runs per-frame from `server-after-make-frame-hook';
+otherwise the value would latch to `unicode' and GUI frames never get images."
+  (setq emojify-display-style (if (env-gui-p) 'image 'unicode)))
+
 (use-package emojify
   :defer 1
   :hook ((erc-mode . emojify-mode))
@@ -221,7 +230,11 @@ the fontset repeatedly is harmless, so it can be called from
   :config
   (setq emojify-show-help nil)
   (setq emojify-point-entered-behaviour 'uncover)
-  (setq emojify-display-style (if (env-gui-p) 'image 'unicode))
+  ;; In daemon mode `env-gui-p' is nil at :config time (no GUI frame yet), so
+  ;; recompute the display style per-frame; otherwise set it now.
+  (if (daemonp)
+      (add-hook 'server-after-make-frame-hook #'cj/set-emojify-display-style)
+    (cj/set-emojify-display-style))
   (setq emojify-emoji-styles '(ascii unicode github))
 
   ;; Disable emojify in programming modes
@@ -242,21 +255,24 @@ the fontset repeatedly is harmless, so it can be called from
   (let ((font-list (font-family-list)))
 	(setq font-list (cl-remove-duplicates (cl-sort font-list 'string-lessp :key 'downcase)))
 	(with-current-buffer "*Available Fonts*"
-	  (erase-buffer)
-	  (dolist (font-family font-list)
-		(insert (propertize (concat font-family) 'face '(font-lock-keyword-face (:weight bold))))
-		(insert (concat "\n"(propertize "Regular: ")))
-		(insert (propertize (concat "The quick brown fox jumps over the lazy dog I 1 l ! : ; . , 0 O o [ { ( ) } ] ?")
-							'face `((:family, font-family))))
-		(insert (concat "\n" (propertize "Bold: ")))
-		(insert (propertize (concat "The quick brown fox jumps over the lazy dog I 1 l ! : ; . , 0 O o [ { ( ) } ] ?")
-							'face `((:family, font-family :weight bold))))
-		(insert (concat "\n" (propertize "Italic: ")))
-		(insert (propertize (concat "The quick brown fox jumps over the lazy dog I 1 l ! : ; . , 0 O o [ { ( ) } ] ?")
-							'face `((:family, font-family :slant italic))))
-		(insert (concat "\n\n"))))
-	(move-to-window-line 0)
-	(special-mode)))
+	  ;; The buffer is left in `special-mode' (read-only) after the first call,
+	  ;; so re-running must relax read-only to erase and rewrite it.
+	  (let ((inhibit-read-only t))
+		(erase-buffer)
+		(dolist (font-family font-list)
+		  (insert (propertize (concat font-family) 'face '(font-lock-keyword-face (:weight bold))))
+		  (insert (concat "\n"(propertize "Regular: ")))
+		  (insert (propertize (concat "The quick brown fox jumps over the lazy dog I 1 l ! : ; . , 0 O o [ { ( ) } ] ?")
+							  'face `((:family, font-family))))
+		  (insert (concat "\n" (propertize "Bold: ")))
+		  (insert (propertize (concat "The quick brown fox jumps over the lazy dog I 1 l ! : ; . , 0 O o [ { ( ) } ] ?")
+							  'face `((:family, font-family :weight bold))))
+		  (insert (concat "\n" (propertize "Italic: ")))
+		  (insert (propertize (concat "The quick brown fox jumps over the lazy dog I 1 l ! : ; . , 0 O o [ { ( ) } ] ?")
+							  'face `((:family, font-family :slant italic))))
+		  (insert (concat "\n\n"))))
+	  (move-to-window-line 0)
+	  (special-mode))))
 
 (keymap-global-set "C-z F" #'cj/display-available-fonts)
 
diff --git a/tests/test-font-config.el b/tests/test-font-config.el
index 393a7758..4df2b41a 100644
--- a/tests/test-font-config.el
+++ b/tests/test-font-config.el
@@ -93,5 +93,47 @@
             ((symbol-function 'set-fontset-font) (lambda (&rest _) t)))
     (should (progn (cj/setup-emoji-fontset) t))))
 
+;;; cj/set-emojify-display-style
+
+(defvar emojify-display-style)
+
+(ert-deftest test-font-config-emojify-display-style-image-on-gui ()
+  "Normal: on a GUI frame the emoji display style is `image'."
+  (skip-unless test-font-config--available)
+  (require 'font-config)
+  (let ((emojify-display-style nil))
+    (cl-letf (((symbol-function 'env-gui-p) (lambda (&rest _) t)))
+      (cj/set-emojify-display-style)
+      (should (eq emojify-display-style 'image)))))
+
+(ert-deftest test-font-config-emojify-display-style-unicode-without-gui ()
+  "Boundary: without a GUI the emoji display style is `unicode'."
+  (skip-unless test-font-config--available)
+  (require 'font-config)
+  (let ((emojify-display-style nil))
+    (cl-letf (((symbol-function 'env-gui-p) (lambda (&rest _) nil)))
+      (cj/set-emojify-display-style)
+      (should (eq emojify-display-style 'unicode)))))
+
+;;; cj/display-available-fonts
+
+(ert-deftest test-font-config-display-available-fonts-second-call-no-error ()
+  "Error: a second invocation does not signal on the read-only buffer."
+  (skip-unless test-font-config--available)
+  (require 'font-config)
+  (cl-letf (((symbol-function 'font-family-list)
+             (lambda (&rest _) '("Fixture Font A" "Fixture Font B"))))
+    (unwind-protect
+        (progn
+          (cj/display-available-fonts)
+          ;; The first call ends in `special-mode' (read-only); the second must
+          ;; not signal when it erases and rewrites the buffer.
+          (cj/display-available-fonts)
+          (with-current-buffer "*Available Fonts*"
+            (should (> (buffer-size) 0))
+            (should buffer-read-only)))
+      (when (get-buffer "*Available Fonts*")
+        (kill-buffer "*Available Fonts*")))))
+
 (provide 'test-font-config)
 ;;; test-font-config.el ends here