bug#33682: 27.0.50; enriched-mode cannot save anonymous faces

bug#33682: 27.0.50; enriched-mode cannot save anonymous faces

[Charles A. Roelli]

C-x C-f /tmp/test-file
M-x enriched-mode RET
M-: (insert (propertize "foo" 'face '(:background "red"))) RET
C-x C-s

Error: Invalid face: :background

The backtrace is:
Debugger entered--Lisp error: (error "Invalid face" :background)
  internal-get-lisp-face-attribute(:background :foreground nil)
  face-attribute(:background :foreground)
  enriched-face-ans(:background)
  enriched-encode-other-face(nil :background)
  format-annotate-atomic-property-change(((bold-italic "bold" "italic") (bold "bold") (italic "italic") (underline "underline") (fixed "fixed") (excerpt "excerpt") (default) (nil enriched-encode-other-face)) nil :background)
  format-annotate-single-property-change(face nil (:background "red") ((face (bold-italic "bold" "italic") (bold "bold") (italic "italic") (underline "underline") (fixed "fixed") (excerpt "excerpt") (default) (nil enriched-encode-other-face)) (left-margin (4 "indent")) (right-margin (4 "indentright")) (justification (none "nofill") (right "flushright") (left "flushleft") (full "flushboth") (center "center")) (PARAMETER (t "param")) (FUNCTION (enriched-decode-foreground "x-color") (enriched-decode-background "x-bg-color") (enriched-decode-display-prop "x-display") (enriched-decode-charset "x-charset")) (read-only (t "x-read-only")) (display (nil enriched-handle-display-prop)) (charset (nil enriched-handle-charset-prop)) (unknown (nil format-annotate-value))))
  format-annotate-location(1 t (front-sticky rear-nonsticky hard) ((face (bold-italic "bold" "italic") (bold "bold") (italic "italic") (underline "underline") (fixed "fixed") (excerpt "excerpt") (default) (nil enriched-encode-other-face)) (left-margin (4 "indent")) (right-margin (4 "indentright")) (justification (none "nofill") (right "flushright") (left "flushleft") (full "flushboth") (center "center")) (PARAMETER (t "param")) (FUNCTION (enriched-decode-foreground "x-color") (enriched-decode-background "x-bg-color") (enriched-decode-display-prop "x-display") (enriched-decode-charset "x-charset")) (read-only (t "x-read-only")) (display (nil enriched-handle-display-prop)) (charset (nil enriched-handle-charset-prop)) (unknown (nil format-annotate-value))))
  format-annotate-region(1 4 ((face (bold-italic "bold" "italic") (bold "bold") (italic "italic") (underline "underline") (fixed "fixed") (excerpt "excerpt") (default) (nil enriched-encode-other-face)) (left-margin (4 "indent")) (right-margin (4 "indentright")) (justification (none "nofill") (right "flushright") (left "flushleft") (full "flushboth") (center "center")) (PARAMETER (t "param")) (FUNCTION (enriched-decode-foreground "x-color") (enriched-decode-background "x-bg-color") (enriched-decode-display-prop "x-display") (enriched-decode-charset "x-charset")) (read-only (t "x-read-only")) (display (nil enriched-handle-display-prop)) (charset (nil enriched-handle-charset-prop)) (unknown (nil format-annotate-value))) enriched-make-annotation (front-sticky rear-nonsticky hard))
  enriched-encode(1 4 #<buffer test-file-3>)
  format-encode-run-method(enriched-encode 1 4 #<buffer test-file-3>)
  format-annotate-function(text/enriched nil nil #<buffer test-file-3> 0)
  write-region(nil nil "/tmp/test-file-3" nil t "/private/tmp/test-file-3")
  basic-save-buffer-2()
  basic-save-buffer-1()
  basic-save-buffer(t)
  save-buffer(1)
  funcall-interactively(save-buffer 1)
  call-interactively(save-buffer nil nil)
  command-execute(save-buffer)


In GNU Emacs 27.0.50 (build 8, x86_64-apple-darwin10.8.0, NS appkit-1038.36 Version 10.6.8 (Build 10K549))
 of 2018-12-09 built on gray
Repository revision: d79bb75683ceb4eee2f753eb38fa8db99aff4568
Repository branch: master
Windowing system distributor 'Apple', version 10.3.1038
System Description:  Mac OS X 10.6.8

bug#33682: 27.0.50; enriched-mode cannot save anonymous faces

[Eli Zaretskii]

> Date: Sun, 09 Dec 2018 11:27:15 +0100
> From: charles@aurox.ch (Charles A. Roelli)
> 
> C-x C-f /tmp/test-file
> M-x enriched-mode RET
> M-: (insert (propertize "foo" 'face '(:background "red"))) RET
> C-x C-s
> 
> Error: Invalid face: :background

Thanks.

When setting colors and other properties in Enriched mode, you are
supposed to use commands from facemenu.el (and/or the menu-bar menu
items it produces, under Edit->Text Properties).

The immediate reason for the error is that you should do this instead:

  M-: (insert (propertize "foo" 'face '((:background "red")))) RET

but I'm not sure we want to extend enriched.el to support arbitrary
face specs.  What is the real-life use case for that?

bug#33682: 27.0.50; enriched-mode cannot save anonymous faces

[Charles A. Roelli]

> Date: Sun, 09 Dec 2018 14:55:39 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> CC: 33682@debbugs.gnu.org
>
> Thanks.
> 
> When setting colors and other properties in Enriched mode, you are
> supposed to use commands from facemenu.el (and/or the menu-bar menu
> items it produces, under Edit->Text Properties).
> 
> The immediate reason for the error is that you should do this instead:
> 
>   M-: (insert (propertize "foo" 'face '((:background "red")))) RET

Thanks for pointing this out.  So enriched mode can save a face
property which is a list of (possibly anonymous) faces, but it chokes
on a single anonymous face.  Is that documented somewhere?

> but I'm not sure we want to extend enriched.el to support arbitrary
> face specs.  What is the real-life use case for that?

Text created by other programs may not be aware of enriched mode's
limitations.  For example, here is an (abbreviated) version of how I
found this bug (from emacs-26):

C-x C-f test/manual/indent/css-mode.css
M-x enriched-mode RET y
C-x C-s

Evidently some text in CSS buffers is fontified with a single
anonymous face, which enriched mode does not support.  For a real-life
use case, if you copy some text from a CSS buffer and yank it in an
enriched mode buffer, the buffer can (temporarily) no longer be saved.

bug#33682: 27.0.50; enriched-mode cannot save anonymous faces

[Eli Zaretskii]

> Date: Sun, 09 Dec 2018 17:35:28 +0100
> From: charles@aurox.ch (Charles A. Roelli)
> CC: 33682@debbugs.gnu.org
> 
> >   M-: (insert (propertize "foo" 'face '((:background "red")))) RET
> 
> Thanks for pointing this out.  So enriched mode can save a face
> property which is a list of (possibly anonymous) faces, but it chokes
> on a single anonymous face.  Is that documented somewhere?

I think the limitation might actually be in format.el, but I didn't
dig deep enough.  Enriched mode is under-used (IMO), and format.el is
even less so, so I'm not surprised they don't support yanking text
with faces from other modes.

> Text created by other programs may not be aware of enriched mode's
> limitations.  For example, here is an (abbreviated) version of how I
> found this bug (from emacs-26):
> 
> C-x C-f test/manual/indent/css-mode.css
> M-x enriched-mode RET y
> C-x C-s
> 
> Evidently some text in CSS buffers is fontified with a single
> anonymous face, which enriched mode does not support.  For a real-life
> use case, if you copy some text from a CSS buffer and yank it in an
> enriched mode buffer, the buffer can (temporarily) no longer be saved.

You (and everyone else) are welcome to work on lifting these
limitations, of course.  Maybe that will make enriched.el more
popular, although I wouldn't hold my breath.

Thanks.

bug#33682: 27.0.50; enriched-mode cannot save anonymous faces

[Lars Ingebrigtsen]

charles@aurox.ch (Charles A. Roelli) writes:

> C-x C-f /tmp/test-file
> M-x enriched-mode RET
> M-: (insert (propertize "foo" 'face '(:background "red"))) RET
> C-x C-s
>
> Error: Invalid face: :background
>
> The backtrace is:
> Debugger entered--Lisp error: (error "Invalid face" :background)
>   internal-get-lisp-face-attribute(:background :foreground nil)

This should now be fixed in Emacs 28.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no