[mcclim-devel] Debugger, ESA, mcclim-freetype

[Christophe Rhodes]

Hi,

Today I observed a rather nasty interaction that I'm at a loss to
explain.  If I wrap the CLIM Debugger around an Emacs-Style
Application which uses mcclim-freetype, and provoke an entry into that
debugger, I get X Length Errors.  I think I need all three of those
elements: the clim debugger and listener work fine together; gsharp
and the clim debugger without freetype work fine; and of course the
applications work acceptably using freetype in normal operation and
with slime.

I am not sure whether this is specific to SBCL; nor am I sure whether
it is specific to threaded lisps; I haven't tried it with a
non-threaded system.  The event queue process has a backtrace that
looks like

Backtrace:
  (BACKTRACE-AS-LIST 200)
  (DEBUGGER-HOOK #<XLIB:LENGTH-ERROR {10060EA641}> #)
  (INVOKE-DEBUGGER #<XLIB:LENGTH-ERROR {10060EA641}>)
  (CERROR "Ignore" XLIB:LENGTH-ERROR)
  (XLIB::X-CERROR "Ignore" XLIB:LENGTH-ERROR :DISPLAY
                  #<XLIB:DISPLAY :0 (The X.Org Foundation R60802000)>
                  :ERROR-KEY XLIB:LENGTH-ERROR :ASYNCHRONOUS T
                  :CURRENT-SEQUENCE 1913 :MAJOR 154 :MINOR 25
                  :SEQUENCE 1563)
  [...]
  (XLIB:PROCESS-EVENT #<XLIB:DISPLAY :0 (The X.Org Foundation R60802000)>
                      :HANDLER # :TIMEOUT NIL :PEEK-P NIL :DISCARD-P T
                      :FORCE-OUTPUT-P T)
  ((SB-PCL::FAST-METHOD CLIM-BACKEND:GET-NEXT-EVENT #) #<unavailable argument>
   #<unavailable argument> 
   #<CLIM-CLX::CLX-PORT :HOST "" :DISPLAY-ID 0 {10059661F1}>
   (:WAIT-FUNCTION NIL :TIMEOUT NIL))

while the application thread (which /also/ gets a length error) has a
backtrace involving HANDLE-REPAINT on the menu-button-pane of the CLIM
Debugger, CLIM-CLX::FONT-DRAW-GLYPHS (MCCLIM-FREETYPE::FREETYPE-FACE
...), and a call to XLIB::DRAWABLE-DEPTH and XLIB::READ-REPLY.

Any ideas?  Can anyone replicate any of this?  Is there something in
the toplevel loop of ESA (or attendant methods) which could cause this
problem?

Cheers,

Christophe