M-x list-buffers is not working anymore: `The value NIL is not of type LEM/COMMON/COLOR:COLOR`

[ryukinix]

Command from keybinding C-x C-b. Error:

The value NIL is not of type LEM/COMMON/COLOR:COLOR
Backtrace for: #<SB-THREAD:THREAD "editor" RUNNING {1009A54293}>
0: (LEM/COMMON/COLOR:RGB-TO-HSV NIL)
1: (LEM/MULTI-COLUMN-LIST::DARKEN-COLOR NIL :FACTOR 0.6)
2: (LEM/MULTI-COLUMN-LIST::PUT-HEADER-ATTRIBUTE #<LEM/BUFFER/INTERNAL:POINT (1, 0) "       Buffer         File " {1007E88223}> #<LEM-CORE:CURSOR (1, 27) "       Buffer         File " {1007E4FF83}>)
3: (LEM/POPUP-MENU::SETUP-MENU-BUFFER #<LEM/BUFFER/INTERNAL:TEXT-BUFFER *popup menu* NIL {1007E43CC3}> (#<LEM/MULTI-COLUMN-LIST::DEFAULT-MULTI-COLUMN-LIST-ITEM {1007E43103}> #<LEM/MULTI-COLUMN-LIST::DEFAULT-MULTI-COLUMN-LIST-ITEM {1007E43143}> #<LEM/MULTI-COLUMN-LIST::DEFAULT-MULTI-COLUMN-LIST-ITEM {1007E43183}> #<LEM/MULTI-COLUMN-LIST::DEFAULT-MULTI-COLUMN-LIST-ITEM {1007E431C3}>) #<LEM/MULTI-COLUMN-LIST::PRINT-SPEC {1007E43B43}> #<LEM-CORE:ATTRIBUTE (white RoyalBlue) {1006696E13}> NIL)
4: ((:METHOD LEM-INTERFACE:DISPLAY-POPUP-MENU (T T)) #<unused argument> (#<LEM/MULTI-COLUMN-LIST::DEFAULT-MULTI-COLUMN-LIST-ITEM {1007E43103}> #<LEM/MULTI-COLUMN-LIST::DEFAULT-MULTI-COLUMN-LIST-ITEM {1007E43143}> #<LEM/MULTI-COLUMN-LIST::DEFAULT-MULTI-COLUMN-LIST-ITEM {1007E43183}> #<LEM/MULTI-COLUMN-LIST::DEFAULT-MULTI-COLUMN-LIST-ITEM {1007E431C3}>) :ACTION-CALLBACK #<FUNCTION (LAMBDA (LEM/MULTI-COLUMN-LIST::ITEM) :IN LEM/MULTI-COLUMN-LIST:DISPLAY) {1007E43B7B}> :PRINT-SPEC #<LEM/MULTI-COLUMN-LIST::PRINT-SPEC {1007E43B43}> :STYLE (:GRAVITY :CENTER) :MAX-DISPLAY-ITEMS 56) [fast-method]
5: ((:METHOD LEM/MULTI-COLUMN-LIST:DISPLAY (LEM/MULTI-COLUMN-LIST:MULTI-COLUMN-LIST)) #<LEM/MULTI-COLUMN-LIST:MULTI-COLUMN-LIST {1007E42F53}> :STYLE (:GRAVITY :CENTER) :INDEX 0) [fast-method]
6: (LEM-CORE:CALL-COMMAND LEM/LIST-BUFFERS:LIST-BUFFERS NIL)
7: (LEM-CORE::COMMAND-LOOP-BODY)
8: (LEM-CORE:COMMAND-LOOP)
9: (LEM-CORE::TOPLEVEL-COMMAND-LOOP #<FUNCTION (LAMBDA NIL :IN LEM-CORE::RUN-EDITOR-THREAD) {10083534BB}>)
10: ((LAMBDA NIL :IN LEM-CORE::RUN-EDITOR-THREAD))
11: ((LAMBDA NIL :IN LEM-CORE::RUN-EDITOR-THREAD))
12: ((FLET BT2::RUN-FUNCTION :IN BT2::ESTABLISH-DYNAMIC-ENV))
13: ((LABELS BT2::%ESTABLISH-DYNAMIC-ENV-WRAPPER :IN BT2::ESTABLISH-DYNAMIC-ENV))
14: ((FLET SB-UNIX::BODY :IN SB-THREAD::RUN))
15: ((FLET "WITHOUT-INTERRUPTS-BODY-10" :IN SB-THREAD::RUN))
16: ((FLET SB-UNIX::BODY :IN SB-THREAD::RUN))
17: ((FLET "WITHOUT-INTERRUPTS-BODY-3" :IN SB-THREAD::RUN))
18: (SB-THREAD::RUN)
19: ("foreign function: call_into_lisp")
20: ("foreign function: funcall1")

Tested:

• Webview from appimage: lem 2.3.0-0b55b4fb (X86-64-PC-003269)
• SDL2 compiled from source: lem 2.3.0-0b55b4fb (X86-64-PC-003269)

This issue doesn't occurs with the ncurses frontend.

Minimal config to reproduce

(define-color-theme "leraxy" ("black-metal-immortal")                                                                                                                                          
  (syntax-keyword-attribute :foreground "dodger blue"))                                                                                                                                        
                                                                                                                                                                                               
(load-theme "leraxy")   

[vindarel]

Hi, it works for me, including on the WebView with the latest AppImage (20250927-0125).

Are you using more modes or color themes?

[ryukinix]

I use a custom theme, but I tried to run without my config and default theme and I got the same error. My config is defined here: https://github.com/ryukinix/dotfiles/blob/master/.lem%2Finit.lisp

[ryukinix]

@vindarel

Yes, I use some modes and custom color-theme. The issue seems related to the definition of color-theme inherited from another. I tried to reproduce the problem with a minimal config and I got this:

(define-color-theme "leraxy" ("black-metal-immortal")                                                                                                                                          
  (syntax-keyword-attribute :foreground "dodger blue"))                                                                                                                                        
                                                                                                                                                                                               
(load-theme "leraxy")   

This is the minimal. I updated the issue description with this, curiously selecting M-x load-theme black-metal-immortal works fine. In previous versions, this piece of code worked with C-x C-b too. For instance, this works fine in release v2.3.0, but not in the latest version from branch main.

[ryukinix]

I confirmed that this version is working properly for me: https://github.com/lem-project/lem/releases/tag/nightly-20250810-0811

Hence the bug was introduced somewhere after the commit e89fac5. Testing 17a5de0, the nightly-latest release, I already can reproduce this issue. So the problem is between these PRs:

git log --oneline --graph 17a5de0ab2529cffb38bbc542182be0e4c25f53f..e89fac5f3d5e5a9e3f53bacd5b8494163e5fc0bc | grep '#'

• 0b55b4f Fixed bugs in lem/link package and added link properties in Markdown Mode (Fixed bugs in lem/link package and added link properties in Markdown Mode #1965)
• 7fe43e2 Merge pull request build legit binary #1949 from vindarel/main
• 82e2773 directory-mode: follow buffer name and directory when moving one file (r) (directory-mode: follow buffer name and directory when moving one file (r) #1945)
• 419cfeb Added option to hide mode lines (Added option to hide mode lines #1941)
• 4e0e5fb update README.md (update README.md #1940)
• b9e9a4b improve pop-up messages after compilation in lisp-mode (improve pop-up messages after compilation in lisp-mode #1938)
• a6ef9d1 Optimize performance: Reduce unnecessary redrawing (Optimize performance: Reduce unnecessary redrawing #1937)
• ba3ddbc Reducing the number of syntax highlight calls (Reducing the number of syntax highlight calls #1936)
• fd0e95b Add terminal.so (Add terminal.so file #1935)
• 291dcff Optimize performance (Optimize performance #1934)
• 4f2713e Claude Code (Claude Code #1929)
• 38a4224 add interactive-mode (Interactive Mode #1928)
• cba817e Add an attached buffer and window (Add an attached buffer and window #1927)
• 58753c3 Remove abundant closing paren (Remove abundant closing paren #1925)
• 9a5df04 Synchronize the position and size of the prompt-window and completion-window (Synchronize the position and size of the prompt-window and completion-window #1924)
• b38a639 Html mode improved syntax highlighting (Html mode improved syntax highlighting #1921)
• 8db63f5 Update appearance (Update appearance #1920)
• cb85c67 Add a feature to customize CSS (Add a feature to customize CSS #1917)
• 50e46e1 Sort commands alphabetically (Sort commands alphabetically in M-x completion window #1913)
• 17c394e Change appearance of list buffers (Change appearance of list buffers #1910)
• a65aaba Set the option to highlight the current line to true by default. (Set the option to highlight the current line to true by default. #1909)
• 6dd1793 tweak (Change the CSS of the floating window border #1907)
• df823c1 Remake command line arguments processor (Remake command line arguments processor #1905)
• 4113df7 "M-x " -> "Comamnd: " ("M-x " -> "Comamnd: " #1901)
• 3bf46bf Automatic tab completion is now set to false by default. Also moved it so that it is accessible for lem package (#1895 #1898)
• cd16e37 Fixes The comment-or-uncomment-region fails to comment in some cases. #1685 (Fixes #1685 #1890)
• 18bfc59 Configurable Automatic Completions (Configurable Automatic Completions #1884)
• 2e36aa7 nightly build (macos) (nightly build (macos) #1883)

[ryukinix]

@vindarel The cause of this problem it seems related with how theme inheritance works related to the methods get-foreground-color and get-background-color are being defined.

Instead of defining this as previously:

(define-color-theme "leraxy" ("black-metal-immortal")                                                                                                                                          
  (syntax-keyword-attribute :foreground "dodger blue"))                                                                                                                                        
                                                                                                                                                                                               
(load-theme "leraxy")   

If I define explicity the foreground/background colors, it works:

(define-color-theme "leraxy" ("black-metal-immortal")
  (:foreground "#c1c1c1") 
  (:background "#000000")
  (syntax-keyword-attribute :foreground "dodger blue"))

Check how these methods are being defined:

lem/src/color-theme.lisp

Lines 109 to 115 in aa7cf1a

	(defun background-color ()
	(when (current-theme)
	(get-color-theme-color (find-color-theme (current-theme)) :background)))
	(defun foreground-color ()
	(when (current-theme)
	(get-color-theme-color (find-color-theme (current-theme)) :foreground)))

If we inspect the object of leraxy and black-metal-immortal we can see that that will not work properly:

However I think the inheritance should consider the parent theme if is not found in the current theme, right?

That's the reason why M-x list-buffers is not working anymore.