bug#31316: Emacs hangs in `font_open_entity'

[Werner LEMBERG]

>> The font is called `emmentaler-brace.otf' (part of lilypond,
>> containing system braces for musical scores).  However, I wonder
>> how this font can ever be considered as a fallback, since its SFNT
>> (3,1) Unicode cmap contains only PUA character codes in the range
>> 0xe100-0xe33f (and `fc-list -v' correctly lists that).  In other
>> words, this font definitely doesn't contain anything relevant to
>> the CJK character codes originally reported.
> 
> I asked for a backtrace from that loop:
> 
>> Please show a C-level backtrace from a breakpoint in that loop.
>> And if the breakpoint breaks more than once when you do nothing
>> after invoking Emacs as shown in your OP, please show the
>> backtraces from all the times that breakpoint breaks.
>>
>> Maybe looking at the backtrace will help us understand why Emacs
>> attempts to open that font.
> 
> Can you please produce that?  I'd like to close this bug report, but
> maybe the backtrace will show us that something else should be done
> here.

Attached. It contains all breaks between loading the test file in
GB18030 encoding and displaying something on screen.

This is still emacs bca6c434 (Apr 29).

Calling `pp entity' at each break shows the following fonts.

  #<font-entity xft 1ASC Droid\ Sans\ Fallback nil iso10646-1 normal normal 
normal 0 nil nil 0 ((:font-entity 
"/usr/share/fonts/truetype/DroidSansFallbackFull.ttf" . 0))>
  #<font-entity xft ADBO Source\ Code\ Pro nil iso10646-1 normal normal normal 
0 nil 100 0 ((:font-entity 
"/usr/share/fonts/truetype/SourceCodePro-Regular.otf" . 0))>
  #<font-entity xft PfEd Emmentaler-Brace nil iso10646-1 normal normal normal 0 
nil 100 0 ((:font-entity 
"/home/wl/.fonts/texlive/opentype/public/lilyglyphs/emmentaler-brace.otf" . 0))>
  #<font-entity xft ADBO Source\ Code\ Pro nil iso10646-1 normal normal normal 
0 nil 100 0 ((:font-entity 
"/usr/share/fonts/truetype/SourceCodePro-Regular.otf" . 0))>
  #<font-entity xft PfEd Emmentaler-Brace nil iso10646-1 normal normal normal 0 
nil 100 0 ((:font-entity 
"/home/wl/.fonts/texlive/opentype/public/lilyglyphs/emmentaler-brace.otf" . 0))>
  #<font-entity xft ADBO Source\ Code\ Pro nil iso10646-1 normal normal normal 
0 nil 100 0 ((:font-entity 
"/usr/share/fonts/truetype/SourceCodePro-Regular.otf" . 0))>
  #<font-entity xft PfEd Emmentaler-Brace nil iso10646-1 normal normal normal 0 
nil 100 0 ((:font-entity 
"/home/wl/.fonts/texlive/opentype/public/lilyglyphs/emmentaler-brace.otf" . 0))>
  #<font-entity xft PfEd Emmentaler-Brace nil iso10646-1 normal normal normal 0 
nil 100 0 ((:font-entity 
"/home/wl/.fonts/texlive/opentype/public/lilyglyphs/emmentaler-brace.otf" . 0))>
  #<font-entity xft PfEd Emmentaler-Brace nil iso10646-1 normal normal normal 0 
nil 100 0 ((:font-entity 
"/home/wl/.fonts/texlive/opentype/public/lilyglyphs/emmentaler-brace.otf" . 0))>
  #<font-entity xft PfEd Emmentaler-Brace nil iso10646-1 normal normal normal 0 
nil 100 0 ((:font-entity 
"/home/wl/.fonts/texlive/opentype/public/lilyglyphs/emmentaler-brace.otf" . 0))>


    Werner

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